mariadb/sql/sql_lex.cc
Dmitry Lenev 6bf6272fda Patch that refactors global read lock implementation and fixes
bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ
LOCK" and bug #54673 "It takes too long to get readlock for
'FLUSH TABLES WITH READ LOCK'".

The first bug manifested itself as a deadlock which occurred
when a connection, which had some table open through HANDLER
statement, tried to update some data through DML statement
while another connection tried to execute FLUSH TABLES WITH
READ LOCK concurrently.

What happened was that FTWRL in the second connection managed
to perform first step of GRL acquisition and thus blocked all
upcoming DML. After that it started to wait for table open
through HANDLER statement to be flushed. When the first connection
tried to execute DML it has started to wait for GRL/the second
connection creating deadlock.

The second bug manifested itself as starvation of FLUSH TABLES
WITH READ LOCK statements in cases when there was a constant
stream of concurrent DML statements (in two or more
connections).

This has happened because requests for protection against GRL
which were acquired by DML statements were ignoring presence of
pending GRL and thus the latter was starved.

This patch solves both these problems by re-implementing GRL
using metadata locks.

Similar to the old implementation acquisition of GRL in new
implementation is two-step. During the first step we block
all concurrent DML and DDL statements by acquiring global S
metadata lock (each DML and DDL statement acquires global IX
lock for its duration). During the second step we block commits
by acquiring global S lock in COMMIT namespace (commit code
acquires global IX lock in this namespace).

Note that unlike in old implementation acquisition of
protection against GRL in DML and DDL is semi-automatic.
We assume that any statement which should be blocked by GRL
will either open and acquires write-lock on tables or acquires
metadata locks on objects it is going to modify. For any such
statement global IX metadata lock is automatically acquired
for its duration.

The first problem is solved because waits for GRL become
visible to deadlock detector in metadata locking subsystem
and thus deadlocks like one in the first bug become impossible.

The second problem is solved because global S locks which
are used for GRL implementation are given preference over
IX locks which are acquired by concurrent DML (and we can
switch to fair scheduling in future if needed).

Important change:
FTWRL/GRL no longer blocks DML and DDL on temporary tables.
Before this patch behavior was not consistent in this respect:
in some cases DML/DDL statements on temporary tables were
blocked while in others they were not. Since the main use cases
for FTWRL are various forms of backups and temporary tables are
not preserved during backups we have opted for consistently
allowing DML/DDL on temporary tables during FTWRL/GRL.

Important change:
This patch changes thread state names which are used when
DML/DDL of FTWRL is waiting for global read lock. It is now
either "Waiting for global read lock" or "Waiting for commit
lock" depending on the stage on which FTWRL is.

Incompatible change:
To solve deadlock in events code which was exposed by this
patch we have to replace LOCK_event_metadata mutex with
metadata locks on events. As result we have to prohibit
DDL on events under LOCK TABLES.

This patch also adds extensive test coverage for interaction
of DML/DDL and FTWRL.

Performance of new and old global read lock implementations
in sysbench tests were compared. There were no significant
difference between new and old implementations.

mysql-test/include/check_ftwrl_compatible.inc:
  Added helper script which allows to check that a statement is
  compatible with FLUSH TABLES WITH READ LOCK.
mysql-test/include/check_ftwrl_incompatible.inc:
  Added helper script which allows to check that a statement is
  incompatible with FLUSH TABLES WITH READ LOCK.
mysql-test/include/handler.inc:
  Adjusted test case to the fact that now DROP TABLE closes
  open HANDLERs for the table to be dropped before checking
  if there active FTWRL in this connection.
mysql-test/include/wait_show_condition.inc:
  Fixed small error in the timeout message. The correct name
  of variable used as parameter for this script is "$condition"
  and not "$wait_condition".
mysql-test/r/delayed.result:
  Added test coverage for scenario which triggered assert in
  metadata locking subsystem.
mysql-test/r/events_2.result:
  Updated test results after prohibiting event DDL operations
  under LOCK TABLES.
mysql-test/r/flush.result:
  Added test coverage for bug #57006 "Deadlock between HANDLER
  and FLUSH TABLES WITH READ LOCK".
mysql-test/r/flush_read_lock.result:
  Added test coverage for various aspects of FLUSH TABLES WITH
  READ LOCK functionality.
mysql-test/r/flush_read_lock_kill.result:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Use new
  debug_sync point. Do not disable concurrent inserts as now
  InnoDB we always use InnoDB table.
mysql-test/r/handler_innodb.result:
  Adjusted test case to the fact that now DROP TABLE closes
  open HANDLERs for the table to be dropped before checking
  if there active FTWRL in this connection.
mysql-test/r/handler_myisam.result:
  Adjusted test case to the fact that now DROP TABLE closes
  open HANDLERs for the table to be dropped before checking
  if there active FTWRL in this connection.
mysql-test/r/mdl_sync.result:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Replaced
  usage of GRL-specific debug_sync's with appropriate sync
  points in MDL subsystem.
mysql-test/suite/perfschema/r/dml_setup_instruments.result:
  Updated test results after removing global
  COND_global_read_lock condition variable.
mysql-test/suite/perfschema/r/func_file_io.result:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/r/func_mutex.result:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/r/global_read_lock.result:
  Adjusted test case to take into account that new GRL
  implementation is based on MDL.
mysql-test/suite/perfschema/r/server_init.result:
  Adjusted test case after replacing custom global read
  lock implementation with one based on MDL and replacing
  LOCK_event_metadata mutex with metadata lock.
mysql-test/suite/perfschema/t/func_file_io.test:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/t/func_mutex.test:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/t/global_read_lock.test:
  Adjusted test case to take into account that new GRL
  implementation is based on MDL.
mysql-test/suite/perfschema/t/server_init.test:
  Adjusted test case after replacing custom global read
  lock implementation with one based on MDL and replacing
  LOCK_event_metadata mutex with metadata lock.
mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result:
  Updated test results after prohibiting event DDL under
  LOCK TABLES.
mysql-test/t/delayed.test:
  Added test coverage for scenario which triggered assert in
  metadata locking subsystem.
mysql-test/t/events_2.test:
  Updated test case after prohibiting event DDL operations
  under LOCK TABLES.
mysql-test/t/flush.test:
  Added test coverage for bug #57006 "Deadlock between HANDLER
  and FLUSH TABLES WITH READ LOCK".
mysql-test/t/flush_block_commit.test:
  Adjusted test case after changing thread state name which
  is used when COMMIT waits for FLUSH TABLES WITH READ LOCK
  from "Waiting for release of readlock" to "Waiting for commit
  lock".
mysql-test/t/flush_block_commit_notembedded.test:
  Adjusted test case after changing thread state name which is
  used when DML waits for FLUSH TABLES WITH READ LOCK. Now we
  use "Waiting for global read lock" in this case.
mysql-test/t/flush_read_lock.test:
  Added test coverage for various aspects of FLUSH TABLES WITH
  READ LOCK functionality.
mysql-test/t/flush_read_lock_kill-master.opt:
  We no longer need to use make_global_read_lock_block_commit_loop
  debug tag in this test. Instead we rely on an appropriate
  debug_sync point in MDL code.
mysql-test/t/flush_read_lock_kill.test:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Use new
  debug_sync point. Do not disable concurrent inserts as now
  InnoDB we always use InnoDB table.
mysql-test/t/lock_multi.test:
  Adjusted test case after changing thread state names which
  are used when DML or DDL waits for FLUSH TABLES WITH READ
  LOCK to "Waiting for global read lock".
mysql-test/t/mdl_sync.test:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Replaced
  usage of GRL-specific debug_sync's with appropriate sync
  points in MDL subsystem. Updated thread state names which
  are used when DDL waits for FTWRL.
mysql-test/t/trigger_notembedded.test:
  Adjusted test case after changing thread state names which
  are used when DML or DDL waits for FLUSH TABLES WITH READ
  LOCK to "Waiting for global read lock".
sql/event_data_objects.cc:
  Removed Event_queue_element::status/last_executed_changed
  members and Event_queue_element::update_timing_fields()
  method. We no longer use this class for updating mysql.events
  once event is chosen for execution. Accesses to instances of
  this class in scheduler thread require protection by
  Event_queue::LOCK_event_queue mutex and we try to avoid
  updating table while holding this lock.
sql/event_data_objects.h:
  Removed Event_queue_element::status/last_executed_changed
  members and Event_queue_element::update_timing_fields()
  method. We no longer use this class for updating mysql.events
  once event is chosen for execution. Accesses to instances of
  this class in scheduler thread require protection by
  Event_queue::LOCK_event_queue mutex and we try to avoid
  updating table while holding this lock.
sql/event_db_repository.cc:
  - Changed Event_db_repository methods to not release all
    metadata locks once they are done updating mysql.events
    table. This allows to keep metadata lock protecting
    against GRL and lock protecting particular event around
    until corresponding DDL statement is written to the binary
    log.
  - Removed logic for conditional update of "status" and
    "last_executed" fields from update_timing_fields_for_event()
    method. In the only case when this method is called now
    "last_executed" is always modified and tracking change
    of "status" is too much hassle.
sql/event_db_repository.h:
  Removed logic for conditional update of "status" and
  "last_executed" fields from Event_db_repository::
  update_timing_fields_for_event() method.
  In the only case when this method is called now "last_executed"
  is always modified and tracking change of "status" field is
  too much hassle.
sql/event_queue.cc:
  Changed event scheduler code not to update mysql.events
  table while holding Event_queue::LOCK_event_queue mutex.
  Doing so led to a deadlock with a new GRL implementation.
  This deadlock didn't occur with old implementation due to
  fact that code acquiring protection against GRL ignored
  pending GRL requests (which lead to GRL starvation).
  One of goals of new implementation is to disallow GRL
  starvation and so we have to solve problem with this
  deadlock in a different way.
sql/events.cc:
  Changed methods of Events class to acquire protection
  against GRL while perfoming DDL statement and keep it
  until statement is written to the binary log.
  Unfortunately this step together with new GRL implementation
  exposed deadlock involving Events::LOCK_event_metadata
  and GRL. To solve it Events::LOCK_event_metadata mutex was
  replaced with a metadata lock on event. As a side-effect
  events DDL has to be prohibited under LOCK TABLES even in
  cases when mysql.events table was explicitly locked for
  write.
sql/events.h:
  Replaced Events::LOCK_event_metadata mutex with a metadata
  lock on event.
sql/ha_ndbcluster.cc:
  Updated code after replacing custom global read lock
  implementation with one based on MDL. Since MDL subsystem
  should now be able to detect deadlocks involving metadata
  locks and GRL there is no need for special handling of
  active GRL.
sql/handler.cc:
  Replaced custom implementation of global read lock with
  one based on metadata locks. Consequently when doing
  commit instead of calling method of Global_read_lock
  class to acquire protection against GRL we simply acquire
  IX in COMMIT namespace.
sql/lock.cc:
  Replaced custom implementation of global read lock with
  one based on metadata locks. This step allows to expose
  wait for GRL to deadlock detector of MDL subsystem and
  thus succesfully resolve deadlocks similar to one behind
  bug #57006 "Deadlock between HANDLER and FLUSH TABLES
  WITH READ LOCK". It also solves problem with GRL starvation
  described in bug #54673 "It takes too long to get readlock
  for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used
  by GRL give preference to FTWRL statement instead of DML
  statements (if needed in future this can be changed to
  fair scheduling).
  
  Similar to old implementation of acquisition of GRL is
  two-step. During the first step we block all concurrent
  DML and DDL statements by acquiring global S metadata lock
  (each DML and DDL statement acquires global IX lock for
  its duration). During the second step we block commits by
  acquiring global S lock in COMMIT namespace (commit code
  acquires global IX lock in this namespace).
  
  Note that unlike in old implementation acquisition of
  protection against GRL in DML and DDL is semi-automatic.
  We assume that any statement which should be blocked by GRL
  will either open and acquires write-lock on tables or acquires
  metadata locks on objects it is going to modify. For any such
  statement global IX metadata lock is automatically acquired
  for its duration.
  
  To support this change:
  - Global_read_lock::lock/unlock_global_read_lock and
    make_global_read_lock_block_commit methods were changed
    accordingly.
  - Global_read_lock::wait_if_global_read_lock() and
    start_waiting_global_read_lock() methods were dropped.
    It is now responsibility of code acquiring metadata locks
    opening tables to acquire protection against GRL by
    explicitly taking global IX lock with statement duration.
  - Global variables, mutex and condition variable used by
    old implementation was removed.
  - lock_routine_name() was changed to use statement duration for
    its global IX lock. It was also renamed to lock_object_name()
    as it now also used to take metadata locks on events.
  - Global_read_lock::set_explicit_lock_duration() was added which
    allows not to release locks used for GRL when leaving prelocked
    mode.
sql/lock.h:
  - Renamed lock_routine_name() to lock_object_name() and changed
    its signature to allow its usage for events.
  - Removed broadcast_refresh() function. It is no longer needed
    with new GRL implementation.
sql/log_event.cc:
  Release metadata locks with statement duration at the end
  of processing legacy event for LOAD DATA. This ensures that
  replication thread processing such event properly releases
  its protection against global read lock.
sql/mdl.cc:
  Changed MDL subsystem to support new MDL-based implementation
  of global read lock.
  
  Added COMMIT and EVENTS namespaces for metadata locks. Changed
  thread state name for GLOBAL namespace to "Waiting for global
  read lock".
  
  Optimized MDL_map::find_or_insert() method to avoid taking
  m_mutex mutex when looking up MDL_lock objects for GLOBAL
  or COMMIT namespaces. We keep pre-created MDL_lock objects
  for these namespaces around and simply return pointers to
  these global objects when needed.
  
  Changed MDL_lock/MDL_scoped_lock to properly handle
  notification of insert delayed handler threads when FTWRL
  takes global S lock.
  
  Introduced concept of lock duration. In addition to locks with
  transaction duration which work in the way which is similar to
  how locks worked before (i.e. they are released at the end of
  transaction), locks with statement and explicit duration were
  introduced.
  Locks with statement duration are automatically released at the
  end of statement. Locks with explicit duration require explicit
  release and obsolete concept of transactional sentinel.
  
  * Changed MDL_request and MDL_ticket classes to support notion
    of duration.
  * Changed MDL_context to keep locks with different duration in
    different lists. Changed code handling ticket list to take
    this into account.
  * Changed methods responsible for releasing locks to take into
    account duration of tickets. Particularly public
    MDL_context::release_lock() method now only can release
    tickets with explicit duration (there is still internal
    method which allows to specify duration). To release locks
    with statement or transaction duration one have to use
    release_statement/transactional_locks() methods.
  * Concept of savepoint for MDL subsystem now has to take into
    account locks with statement duration. Consequently
    MDL_savepoint class was introduced and methods working with
    savepoints were updated accordingly.
  * Added methods which allow to set duration for one or all
    locks in the context.
sql/mdl.h:
  Changed MDL subsystem to support new MDL-based implementation
  of global read lock.
  
  Added COMMIT and EVENTS namespaces for metadata locks.
  
  Introduced concept of lock duration. In addition to locks with
  transaction duration which work in the way which is similar to
  how locks worked before (i.e. they are released at the end of
  transaction), locks with statement and explicit duration were
  introduced.
  Locks with statement duration are automatically released at the
  end of statement. Locks with explicit duration require explicit
  release and obsolete concept of transactional sentinel.
  
  * Changed MDL_request and MDL_ticket classes to support notion
    of duration.
  * Changed MDL_context to keep locks with different duration in
    different lists. Changed code handling ticket list to take
    this into account.
  * Changed methods responsible for releasing locks to take into
    account duration of tickets. Particularly public
    MDL_context::release_lock() method now only can release
    tickets with explicit duration (there is still internal
    method which allows to specify duration). To release locks
    with statement or transaction duration one have to use
    release_statement/transactional_locks() methods.
  * Concept of savepoint for MDL subsystem now has to take into
    account locks with statement duration. Consequently
    MDL_savepoint class was introduced and methods working with
    savepoints were updated accordingly.
  * Added methods which allow to set duration for one or all
    locks in the context.
sql/mysqld.cc:
  Removed global mutex and condition variables which were used
  by old implementation of GRL.
  Also we no longer need to initialize Events::LOCK_event_metadata
  mutex as it was replaced with metadata locks on events.
sql/mysqld.h:
  Removed global variable, mutex and condition variables which
  were used by old implementation of GRL.
sql/rpl_rli.cc:
  When slave thread closes tables which were open for handling
  of RBR events ensure that it releases global IX lock which
  was acquired as protection against GRL.
sql/sp.cc:
  Adjusted code to the new signature of lock_object/routine_name(),
  to the fact that one now needs specify duration of lock when
  initializing MDL_request and to the fact that savepoints for MDL
  subsystem are now represented by MDL_savepoint class.
sql/sp_head.cc:
  Ensure that statements in stored procedures release statement
  metadata locks and thus release their protectiong against GRL
  in proper moment in time.
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/sql_admin.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/sql_base.cc:
  - Implemented support for new approach to acquiring protection
    against global read lock. We no longer acquire such protection
    explicitly on the basis of statement flags. Instead we always
    rely on code which is responsible for acquiring metadata locks
    on object to be changed acquiring this protection. This is
    achieved by acquiring global IX metadata lock with statement
    duration. Code doing this also responsible for checking that
    current connection has no active GRL by calling an
    Global_read_lock::can_acquire_protection() method.
    Changed code in open_table() and lock_table_names()
    accordingly.
    Note that as result of this change DDL and DML on temporary
    tables is always compatible with GRL (before it was
    incompatible in some cases and compatible in other cases).
  - To speed-up code acquiring protection against GRL introduced
    m_has_protection_against_grl member in Open_table_context
    class. It indicates that protection was already acquired
    sometime during open_tables() execution and new attempts
    can be skipped.
  - Thanks to new GRL implementation calls to broadcast_refresh()
    became unnecessary and were removed.
  - Adjusted code to the fact that one now needs specify duration
    of lock when initializing MDL_request and to the fact that
    savepoints for MDL subsystem are now represented by
    MDL_savepoint class.
sql/sql_base.h:
  Adjusted code to the fact that savepoints for MDL subsystem are
  now represented by MDL_savepoint class.
  Also introduced Open_table_context::m_has_protection_against_grl
  member which allows to avoid acquiring protection against GRL
  while opening tables if such protection was already acquired.
sql/sql_class.cc:
  Changed THD::leave_locked_tables_mode() after transactional
  sentinel for metadata locks was obsoleted by introduction of
  locks with explicit duration.
sql/sql_class.h:
  - Adjusted code to the fact that savepoints for MDL subsystem
    are now represented by MDL_savepoint class.
  - Changed Global_read_lock class according to changes in
    global read lock implementation:
    * wait_if_global_read_lock and start_waiting_global_read_lock
      are now gone. Instead code needing protection against GRL
      has to acquire global IX metadata lock with statement
      duration itself. To help it new can_acquire_protection()
      was introduced. Also as result of the above change
      m_protection_count member is gone too.
    * Added m_mdl_blocks_commits_lock member to store metadata
      lock blocking commits.
    * Adjusted code to the fact that concept of transactional
      sentinel was obsoleted by concept of lock duration.
  - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer
    necessary. New GRL implementation acquires protection
    against global read lock automagically when statement
    acquires metadata locks on tables or other objects it
    is going to change.
sql/sql_db.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/sql_handler.cc:
  Removed call to broadcast_refresh() function. It is no longer
  needed with new GRL implementation.
  Adjusted code after introducing duration concept for metadata
  locks. Particularly to the fact transactional sentinel was
  replaced with explicit duration.
sql/sql_handler.h:
  Renamed mysql_ha_move_tickets_after_trans_sentinel() to
  mysql_ha_set_explicit_lock_duration() after transactional
  sentinel was obsoleted by locks with explicit duration.
sql/sql_insert.cc:
  Adjusted code handling delaying inserts after switching to
  new GRL implementation. Now connection thread initiating
  delayed insert has to acquire global IX lock in addition
  to metadata lock on table being inserted into. This IX lock
  protects against GRL and similarly to SW lock on table being
  inserted into has to be passed to handler thread in order to
  avoid deadlocks.
sql/sql_lex.cc:
  LEX::protect_against_global_read_lock member is no longer
  necessary since protection against GRL is automatically
  taken by code acquiring metadata locks/opening tables.
sql/sql_lex.h:
  LEX::protect_against_global_read_lock member is no longer
  necessary since protection against GRL is automatically
  taken by code acquiring metadata locks/opening tables.
sql/sql_parse.cc:
  - Implemented support for new approach to acquiring protection
    against global read lock. We no longer acquire such protection
    explicitly on the basis of statement flags. Instead we always
    rely on code which is responsible for acquiring metadata locks
    on object to be changed acquiring this protection. This is
    achieved by acquiring global IX metadata lock with statement
    duration. This lock is automatically released at the end of
    statement execution.
  - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not
    to release metadata locks and thus protection against of GRL
    in the middle of statement execution.
  - Adjusted code to the fact that one now needs specify duration
    of lock when initializing MDL_request and to the fact that
    savepoints for MDL subsystem are now represented by
    MDL_savepoint class.
sql/sql_prepare.cc:
  Adjusted code to the to the fact that savepoints for MDL
  subsystem are now represented by MDL_savepoint class.
sql/sql_rename.cc:
  With new GRL implementation there is no need to explicitly
  acquire protection against GRL before renaming tables.
  This happens automatically in code which acquires metadata
  locks on tables being renamed.
sql/sql_show.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request and to the fact that
  savepoints for MDL subsystem are now represented by
  MDL_savepoint class.
sql/sql_table.cc:
  - With new GRL implementation there is no need to explicitly
    acquire protection against GRL before dropping tables.
    This happens automatically in code which acquires metadata
    locks on tables being dropped.
  - Changed mysql_alter_table() not to release lock on new table
    name explicitly and to rely on automatic release of locks
    at the end of statement instead. This was necessary since
    now MDL_context::release_lock() is supported only for locks
    for explicit duration.
sql/sql_trigger.cc:
  With new GRL implementation there is no need to explicitly
  acquire protection against GRL before changing table triggers.
  This happens automatically in code which acquires metadata
  locks on tables which triggers are to be changed.
sql/sql_update.cc:
  Fix bug exposed by GRL testing. During prepare phase acquire
  only S metadata locks instead of SW locks to keep prepare of
  multi-UPDATE compatible with concurrent LOCK TABLES WRITE
  and global read lock.
sql/sql_view.cc:
  With new GRL implementation there is no need to explicitly
  acquire protection against GRL before creating view.
  This happens automatically in code which acquires metadata
  lock on view to be created.
sql/sql_yacc.yy:
  LEX::protect_against_global_read_lock member is no longer
  necessary since protection against GRL is automatically
  taken by code acquiring metadata locks/opening tables.
sql/table.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/table.h:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/transaction.cc:
  Replaced custom implementation of global read lock with
  one based on metadata locks. Consequently when doing
  commit instead of calling method of Global_read_lock
  class to acquire protection against GRL we simply acquire
  IX in COMMIT namespace.
  Also adjusted code to the fact that MDL savepoint is now
  represented by MDL_savepoint class.
2010-11-11 20:11:05 +03:00

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/* Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* A lexical scanner on a temporary buffer with a yacc interface */
#define MYSQL_LEX 1
#include "sql_priv.h"
#include "unireg.h" // REQUIRED: for other includes
#include "sql_class.h" // sql_lex.h: SQLCOM_END
#include "sql_lex.h"
#include "sql_parse.h" // add_to_list
#include "item_create.h"
#include <m_ctype.h>
#include <hash.h>
#include "sp.h"
#include "sp_head.h"
static int lex_one_token(void *arg, void *yythd);
/*
We are using pointer to this variable for distinguishing between assignment
to NEW row field (when parsing trigger definition) and structured variable.
*/
sys_var *trg_new_row_fake_var= (sys_var*) 0x01;
/**
LEX_STRING constant for null-string to be used in parser and other places.
*/
const LEX_STRING null_lex_str= {NULL, 0};
const LEX_STRING empty_lex_str= {(char *) "", 0};
/**
@note The order of the elements of this array must correspond to
the order of elements in enum_binlog_stmt_unsafe.
*/
const int
Query_tables_list::binlog_stmt_unsafe_errcode[BINLOG_STMT_UNSAFE_COUNT] =
{
ER_BINLOG_UNSAFE_LIMIT,
ER_BINLOG_UNSAFE_INSERT_DELAYED,
ER_BINLOG_UNSAFE_SYSTEM_TABLE,
ER_BINLOG_UNSAFE_AUTOINC_COLUMNS,
ER_BINLOG_UNSAFE_UDF,
ER_BINLOG_UNSAFE_SYSTEM_VARIABLE,
ER_BINLOG_UNSAFE_SYSTEM_FUNCTION,
ER_BINLOG_UNSAFE_NONTRANS_AFTER_TRANS,
ER_BINLOG_UNSAFE_MULTIPLE_ENGINES_AND_SELF_LOGGING_ENGINE,
ER_BINLOG_UNSAFE_MIXED_STATEMENT,
};
/* Longest standard keyword name */
#define TOCK_NAME_LENGTH 24
/*
The following data is based on the latin1 character set, and is only
used when comparing keywords
*/
static uchar to_upper_lex[]=
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95,
96, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,123,124,125,126,127,
128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,
176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
208,209,210,211,212,213,214,247,216,217,218,219,220,221,222,255
};
/*
Names of the index hints (for error messages). Keep in sync with
index_hint_type
*/
const char * index_hint_type_name[] =
{
"IGNORE INDEX",
"USE INDEX",
"FORCE INDEX"
};
inline int lex_casecmp(const char *s, const char *t, uint len)
{
while (len-- != 0 &&
to_upper_lex[(uchar) *s++] == to_upper_lex[(uchar) *t++]) ;
return (int) len+1;
}
#include <lex_hash.h>
void lex_init(void)
{
uint i;
DBUG_ENTER("lex_init");
for (i=0 ; i < array_elements(symbols) ; i++)
symbols[i].length=(uchar) strlen(symbols[i].name);
for (i=0 ; i < array_elements(sql_functions) ; i++)
sql_functions[i].length=(uchar) strlen(sql_functions[i].name);
DBUG_VOID_RETURN;
}
void lex_free(void)
{ // Call this when daemon ends
DBUG_ENTER("lex_free");
DBUG_VOID_RETURN;
}
void
st_parsing_options::reset()
{
allows_variable= TRUE;
allows_select_into= TRUE;
allows_select_procedure= TRUE;
allows_derived= TRUE;
}
/**
Perform initialization of Lex_input_stream instance.
Basically, a buffer for pre-processed query. This buffer should be large
enough to keep multi-statement query. The allocation is done once in
Lex_input_stream::init() in order to prevent memory pollution when
the server is processing large multi-statement queries.
*/
bool Lex_input_stream::init(THD *thd,
char* buff,
unsigned int length)
{
DBUG_EXECUTE_IF("bug42064_simulate_oom",
DBUG_SET("+d,simulate_out_of_memory"););
m_cpp_buf= (char*) thd->alloc(length + 1);
DBUG_EXECUTE_IF("bug42064_simulate_oom",
DBUG_SET("-d,bug42064_simulate_oom"););
if (m_cpp_buf == NULL)
return TRUE;
m_thd= thd;
reset(buff, length);
return FALSE;
}
/**
Prepare Lex_input_stream instance state for use for handling next SQL statement.
It should be called between two statements in a multi-statement query.
The operation resets the input stream to the beginning-of-parse state,
but does not reallocate m_cpp_buf.
*/
void
Lex_input_stream::reset(char *buffer, unsigned int length)
{
yylineno= 1;
yytoklen= 0;
yylval= NULL;
lookahead_token= -1;
lookahead_yylval= NULL;
m_ptr= buffer;
m_tok_start= NULL;
m_tok_end= NULL;
m_end_of_query= buffer + length;
m_tok_start_prev= NULL;
m_buf= buffer;
m_buf_length= length;
m_echo= TRUE;
m_cpp_tok_start= NULL;
m_cpp_tok_start_prev= NULL;
m_cpp_tok_end= NULL;
m_body_utf8= NULL;
m_cpp_utf8_processed_ptr= NULL;
next_state= MY_LEX_START;
found_semicolon= NULL;
ignore_space= test(m_thd->variables.sql_mode & MODE_IGNORE_SPACE);
stmt_prepare_mode= FALSE;
multi_statements= TRUE;
in_comment=NO_COMMENT;
m_underscore_cs= NULL;
m_cpp_ptr= m_cpp_buf;
}
/**
The operation is called from the parser in order to
1) designate the intention to have utf8 body;
1) Indicate to the lexer that we will need a utf8 representation of this
statement;
2) Determine the beginning of the body.
@param thd Thread context.
@param begin_ptr Pointer to the start of the body in the pre-processed
buffer.
*/
void Lex_input_stream::body_utf8_start(THD *thd, const char *begin_ptr)
{
DBUG_ASSERT(begin_ptr);
DBUG_ASSERT(m_cpp_buf <= begin_ptr && begin_ptr <= m_cpp_buf + m_buf_length);
uint body_utf8_length=
(m_buf_length / thd->variables.character_set_client->mbminlen) *
my_charset_utf8_bin.mbmaxlen;
m_body_utf8= (char *) thd->alloc(body_utf8_length + 1);
m_body_utf8_ptr= m_body_utf8;
*m_body_utf8_ptr= 0;
m_cpp_utf8_processed_ptr= begin_ptr;
}
/**
@brief The operation appends unprocessed part of pre-processed buffer till
the given pointer (ptr) and sets m_cpp_utf8_processed_ptr to end_ptr.
The idea is that some tokens in the pre-processed buffer (like character
set introducers) should be skipped.
Example:
CPP buffer: SELECT 'str1', _latin1 'str2';
m_cpp_utf8_processed_ptr -- points at the "SELECT ...";
In order to skip "_latin1", the following call should be made:
body_utf8_append(<pointer to "_latin1 ...">, <pointer to " 'str2'...">)
@param ptr Pointer in the pre-processed buffer, which specifies the
end of the chunk, which should be appended to the utf8
body.
@param end_ptr Pointer in the pre-processed buffer, to which
m_cpp_utf8_processed_ptr will be set in the end of the
operation.
*/
void Lex_input_stream::body_utf8_append(const char *ptr,
const char *end_ptr)
{
DBUG_ASSERT(m_cpp_buf <= ptr && ptr <= m_cpp_buf + m_buf_length);
DBUG_ASSERT(m_cpp_buf <= end_ptr && end_ptr <= m_cpp_buf + m_buf_length);
if (!m_body_utf8)
return;
if (m_cpp_utf8_processed_ptr >= ptr)
return;
int bytes_to_copy= ptr - m_cpp_utf8_processed_ptr;
memcpy(m_body_utf8_ptr, m_cpp_utf8_processed_ptr, bytes_to_copy);
m_body_utf8_ptr += bytes_to_copy;
*m_body_utf8_ptr= 0;
m_cpp_utf8_processed_ptr= end_ptr;
}
/**
The operation appends unprocessed part of the pre-processed buffer till
the given pointer (ptr) and sets m_cpp_utf8_processed_ptr to ptr.
@param ptr Pointer in the pre-processed buffer, which specifies the end
of the chunk, which should be appended to the utf8 body.
*/
void Lex_input_stream::body_utf8_append(const char *ptr)
{
body_utf8_append(ptr, ptr);
}
/**
The operation converts the specified text literal to the utf8 and appends
the result to the utf8-body.
@param thd Thread context.
@param txt Text literal.
@param txt_cs Character set of the text literal.
@param end_ptr Pointer in the pre-processed buffer, to which
m_cpp_utf8_processed_ptr will be set in the end of the
operation.
*/
void Lex_input_stream::body_utf8_append_literal(THD *thd,
const LEX_STRING *txt,
CHARSET_INFO *txt_cs,
const char *end_ptr)
{
if (!m_cpp_utf8_processed_ptr)
return;
LEX_STRING utf_txt;
if (!my_charset_same(txt_cs, &my_charset_utf8_general_ci))
{
thd->convert_string(&utf_txt,
&my_charset_utf8_general_ci,
txt->str, (uint) txt->length,
txt_cs);
}
else
{
utf_txt.str= txt->str;
utf_txt.length= txt->length;
}
/* NOTE: utf_txt.length is in bytes, not in symbols. */
memcpy(m_body_utf8_ptr, utf_txt.str, utf_txt.length);
m_body_utf8_ptr += utf_txt.length;
*m_body_utf8_ptr= 0;
m_cpp_utf8_processed_ptr= end_ptr;
}
/*
This is called before every query that is to be parsed.
Because of this, it's critical to not do too much things here.
(We already do too much here)
*/
void lex_start(THD *thd)
{
LEX *lex= thd->lex;
DBUG_ENTER("lex_start");
lex->thd= lex->unit.thd= thd;
lex->context_stack.empty();
lex->unit.init_query();
lex->unit.init_select();
/* 'parent_lex' is used in init_query() so it must be before it. */
lex->select_lex.parent_lex= lex;
lex->select_lex.init_query();
lex->value_list.empty();
lex->update_list.empty();
lex->set_var_list.empty();
lex->param_list.empty();
lex->view_list.empty();
lex->prepared_stmt_params.empty();
lex->auxiliary_table_list.empty();
lex->unit.next= lex->unit.master=
lex->unit.link_next= lex->unit.return_to= 0;
lex->unit.prev= lex->unit.link_prev= 0;
lex->unit.slave= lex->unit.global_parameters= lex->current_select=
lex->all_selects_list= &lex->select_lex;
lex->select_lex.master= &lex->unit;
lex->select_lex.prev= &lex->unit.slave;
lex->select_lex.link_next= lex->select_lex.slave= lex->select_lex.next= 0;
lex->select_lex.link_prev= (st_select_lex_node**)&(lex->all_selects_list);
lex->select_lex.options= 0;
lex->select_lex.sql_cache= SELECT_LEX::SQL_CACHE_UNSPECIFIED;
lex->select_lex.init_order();
lex->select_lex.group_list.empty();
lex->describe= 0;
lex->subqueries= FALSE;
lex->view_prepare_mode= FALSE;
lex->derived_tables= 0;
lex->safe_to_cache_query= 1;
lex->leaf_tables_insert= 0;
lex->parsing_options.reset();
lex->empty_field_list_on_rset= 0;
lex->select_lex.select_number= 1;
lex->length=0;
lex->part_info= 0;
lex->select_lex.in_sum_expr=0;
lex->select_lex.ftfunc_list_alloc.empty();
lex->select_lex.ftfunc_list= &lex->select_lex.ftfunc_list_alloc;
lex->select_lex.group_list.empty();
lex->select_lex.order_list.empty();
lex->duplicates= DUP_ERROR;
lex->ignore= 0;
lex->spname= NULL;
lex->sphead= NULL;
lex->spcont= NULL;
lex->m_stmt= NULL;
lex->proc_list.first= 0;
lex->escape_used= FALSE;
lex->query_tables= 0;
lex->reset_query_tables_list(FALSE);
lex->expr_allows_subselect= TRUE;
lex->use_only_table_context= FALSE;
lex->name.str= 0;
lex->name.length= 0;
lex->event_parse_data= NULL;
lex->profile_options= PROFILE_NONE;
lex->nest_level=0 ;
lex->allow_sum_func= 0;
lex->in_sum_func= NULL;
/*
ok, there must be a better solution for this, long-term
I tried "bzero" in the sql_yacc.yy code, but that for
some reason made the values zero, even if they were set
*/
lex->server_options.server_name= 0;
lex->server_options.server_name_length= 0;
lex->server_options.host= 0;
lex->server_options.db= 0;
lex->server_options.username= 0;
lex->server_options.password= 0;
lex->server_options.scheme= 0;
lex->server_options.socket= 0;
lex->server_options.owner= 0;
lex->server_options.port= -1;
lex->is_lex_started= TRUE;
DBUG_VOID_RETURN;
}
void lex_end(LEX *lex)
{
DBUG_ENTER("lex_end");
DBUG_PRINT("enter", ("lex: 0x%lx", (long) lex));
/* release used plugins */
if (lex->plugins.elements) /* No function call and no mutex if no plugins. */
{
plugin_unlock_list(0, (plugin_ref*)lex->plugins.buffer,
lex->plugins.elements);
}
reset_dynamic(&lex->plugins);
delete lex->sphead;
lex->sphead= NULL;
DBUG_VOID_RETURN;
}
Yacc_state::~Yacc_state()
{
if (yacc_yyss)
{
my_free(yacc_yyss);
my_free(yacc_yyvs);
}
}
static int find_keyword(Lex_input_stream *lip, uint len, bool function)
{
const char *tok= lip->get_tok_start();
SYMBOL *symbol= get_hash_symbol(tok, len, function);
if (symbol)
{
lip->yylval->symbol.symbol=symbol;
lip->yylval->symbol.str= (char*) tok;
lip->yylval->symbol.length=len;
if ((symbol->tok == NOT_SYM) &&
(lip->m_thd->variables.sql_mode & MODE_HIGH_NOT_PRECEDENCE))
return NOT2_SYM;
if ((symbol->tok == OR_OR_SYM) &&
!(lip->m_thd->variables.sql_mode & MODE_PIPES_AS_CONCAT))
return OR2_SYM;
return symbol->tok;
}
return 0;
}
/*
Check if name is a keyword
SYNOPSIS
is_keyword()
name checked name (must not be empty)
len length of checked name
RETURN VALUES
0 name is a keyword
1 name isn't a keyword
*/
bool is_keyword(const char *name, uint len)
{
DBUG_ASSERT(len != 0);
return get_hash_symbol(name,len,0)!=0;
}
/**
Check if name is a sql function
@param name checked name
@return is this a native function or not
@retval 0 name is a function
@retval 1 name isn't a function
*/
bool is_lex_native_function(const LEX_STRING *name)
{
DBUG_ASSERT(name != NULL);
return (get_hash_symbol(name->str, (uint) name->length, 1) != 0);
}
/* make a copy of token before ptr and set yytoklen */
static LEX_STRING get_token(Lex_input_stream *lip, uint skip, uint length)
{
LEX_STRING tmp;
lip->yyUnget(); // ptr points now after last token char
tmp.length=lip->yytoklen=length;
tmp.str= lip->m_thd->strmake(lip->get_tok_start() + skip, tmp.length);
lip->m_cpp_text_start= lip->get_cpp_tok_start() + skip;
lip->m_cpp_text_end= lip->m_cpp_text_start + tmp.length;
return tmp;
}
/*
todo:
There are no dangerous charsets in mysql for function
get_quoted_token yet. But it should be fixed in the
future to operate multichar strings (like ucs2)
*/
static LEX_STRING get_quoted_token(Lex_input_stream *lip,
uint skip,
uint length, char quote)
{
LEX_STRING tmp;
const char *from, *end;
char *to;
lip->yyUnget(); // ptr points now after last token char
tmp.length= lip->yytoklen=length;
tmp.str=(char*) lip->m_thd->alloc(tmp.length+1);
from= lip->get_tok_start() + skip;
to= tmp.str;
end= to+length;
lip->m_cpp_text_start= lip->get_cpp_tok_start() + skip;
lip->m_cpp_text_end= lip->m_cpp_text_start + length;
for ( ; to != end; )
{
if ((*to++= *from++) == quote)
{
from++; // Skip double quotes
lip->m_cpp_text_start++;
}
}
*to= 0; // End null for safety
return tmp;
}
/*
Return an unescaped text literal without quotes
Fix sometimes to do only one scan of the string
*/
static char *get_text(Lex_input_stream *lip, int pre_skip, int post_skip)
{
reg1 uchar c,sep;
uint found_escape=0;
CHARSET_INFO *cs= lip->m_thd->charset();
lip->tok_bitmap= 0;
sep= lip->yyGetLast(); // String should end with this
while (! lip->eof())
{
c= lip->yyGet();
lip->tok_bitmap|= c;
#ifdef USE_MB
{
int l;
if (use_mb(cs) &&
(l = my_ismbchar(cs,
lip->get_ptr() -1,
lip->get_end_of_query()))) {
lip->skip_binary(l-1);
continue;
}
}
#endif
if (c == '\\' &&
!(lip->m_thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES))
{ // Escaped character
found_escape=1;
if (lip->eof())
return 0;
lip->yySkip();
}
else if (c == sep)
{
if (c == lip->yyGet()) // Check if two separators in a row
{
found_escape=1; // duplicate. Remember for delete
continue;
}
else
lip->yyUnget();
/* Found end. Unescape and return string */
const char *str, *end;
char *start;
str= lip->get_tok_start();
end= lip->get_ptr();
/* Extract the text from the token */
str += pre_skip;
end -= post_skip;
DBUG_ASSERT(end >= str);
if (!(start= (char*) lip->m_thd->alloc((uint) (end-str)+1)))
return (char*) ""; // Sql_alloc has set error flag
lip->m_cpp_text_start= lip->get_cpp_tok_start() + pre_skip;
lip->m_cpp_text_end= lip->get_cpp_ptr() - post_skip;
if (!found_escape)
{
lip->yytoklen=(uint) (end-str);
memcpy(start,str,lip->yytoklen);
start[lip->yytoklen]=0;
}
else
{
char *to;
for (to=start ; str != end ; str++)
{
#ifdef USE_MB
int l;
if (use_mb(cs) &&
(l = my_ismbchar(cs, str, end))) {
while (l--)
*to++ = *str++;
str--;
continue;
}
#endif
if (!(lip->m_thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES) &&
*str == '\\' && str+1 != end)
{
switch(*++str) {
case 'n':
*to++='\n';
break;
case 't':
*to++= '\t';
break;
case 'r':
*to++ = '\r';
break;
case 'b':
*to++ = '\b';
break;
case '0':
*to++= 0; // Ascii null
break;
case 'Z': // ^Z must be escaped on Win32
*to++='\032';
break;
case '_':
case '%':
*to++= '\\'; // remember prefix for wildcard
/* Fall through */
default:
*to++= *str;
break;
}
}
else if (*str == sep)
*to++= *str++; // Two ' or "
else
*to++ = *str;
}
*to=0;
lip->yytoklen=(uint) (to-start);
}
return start;
}
}
return 0; // unexpected end of query
}
/*
** Calc type of integer; long integer, longlong integer or real.
** Returns smallest type that match the string.
** When using unsigned long long values the result is converted to a real
** because else they will be unexpected sign changes because all calculation
** is done with longlong or double.
*/
static const char *long_str="2147483647";
static const uint long_len=10;
static const char *signed_long_str="-2147483648";
static const char *longlong_str="9223372036854775807";
static const uint longlong_len=19;
static const char *signed_longlong_str="-9223372036854775808";
static const uint signed_longlong_len=19;
static const char *unsigned_longlong_str="18446744073709551615";
static const uint unsigned_longlong_len=20;
static inline uint int_token(const char *str,uint length)
{
if (length < long_len) // quick normal case
return NUM;
bool neg=0;
if (*str == '+') // Remove sign and pre-zeros
{
str++; length--;
}
else if (*str == '-')
{
str++; length--;
neg=1;
}
while (*str == '0' && length)
{
str++; length --;
}
if (length < long_len)
return NUM;
uint smaller,bigger;
const char *cmp;
if (neg)
{
if (length == long_len)
{
cmp= signed_long_str+1;
smaller=NUM; // If <= signed_long_str
bigger=LONG_NUM; // If >= signed_long_str
}
else if (length < signed_longlong_len)
return LONG_NUM;
else if (length > signed_longlong_len)
return DECIMAL_NUM;
else
{
cmp=signed_longlong_str+1;
smaller=LONG_NUM; // If <= signed_longlong_str
bigger=DECIMAL_NUM;
}
}
else
{
if (length == long_len)
{
cmp= long_str;
smaller=NUM;
bigger=LONG_NUM;
}
else if (length < longlong_len)
return LONG_NUM;
else if (length > longlong_len)
{
if (length > unsigned_longlong_len)
return DECIMAL_NUM;
cmp=unsigned_longlong_str;
smaller=ULONGLONG_NUM;
bigger=DECIMAL_NUM;
}
else
{
cmp=longlong_str;
smaller=LONG_NUM;
bigger= ULONGLONG_NUM;
}
}
while (*cmp && *cmp++ == *str++) ;
return ((uchar) str[-1] <= (uchar) cmp[-1]) ? smaller : bigger;
}
/**
Given a stream that is advanced to the first contained character in
an open comment, consume the comment. Optionally, if we are allowed,
recurse so that we understand comments within this current comment.
At this level, we do not support version-condition comments. We might
have been called with having just passed one in the stream, though. In
that case, we probably want to tolerate mundane comments inside. Thus,
the case for recursion.
@retval Whether EOF reached before comment is closed.
*/
bool consume_comment(Lex_input_stream *lip, int remaining_recursions_permitted)
{
reg1 uchar c;
while (! lip->eof())
{
c= lip->yyGet();
if (remaining_recursions_permitted > 0)
{
if ((c == '/') && (lip->yyPeek() == '*'))
{
lip->yySkip(); /* Eat asterisk */
consume_comment(lip, remaining_recursions_permitted-1);
continue;
}
}
if (c == '*')
{
if (lip->yyPeek() == '/')
{
lip->yySkip(); /* Eat slash */
return FALSE;
}
}
if (c == '\n')
lip->yylineno++;
}
return TRUE;
}
/*
MYSQLlex remember the following states from the following MYSQLlex()
- MY_LEX_EOQ Found end of query
- MY_LEX_OPERATOR_OR_IDENT Last state was an ident, text or number
(which can't be followed by a signed number)
*/
int MYSQLlex(void *arg, void *yythd)
{
THD *thd= (THD *)yythd;
Lex_input_stream *lip= & thd->m_parser_state->m_lip;
YYSTYPE *yylval=(YYSTYPE*) arg;
int token;
if (lip->lookahead_token >= 0)
{
/*
The next token was already parsed in advance,
return it.
*/
token= lip->lookahead_token;
lip->lookahead_token= -1;
*yylval= *(lip->lookahead_yylval);
lip->lookahead_yylval= NULL;
return token;
}
token= lex_one_token(arg, yythd);
switch(token) {
case WITH:
/*
Parsing 'WITH' 'ROLLUP' or 'WITH' 'CUBE' requires 2 look ups,
which makes the grammar LALR(2).
Replace by a single 'WITH_ROLLUP' or 'WITH_CUBE' token,
to transform the grammar into a LALR(1) grammar,
which sql_yacc.yy can process.
*/
token= lex_one_token(arg, yythd);
switch(token) {
case CUBE_SYM:
return WITH_CUBE_SYM;
case ROLLUP_SYM:
return WITH_ROLLUP_SYM;
default:
/*
Save the token following 'WITH'
*/
lip->lookahead_yylval= lip->yylval;
lip->yylval= NULL;
lip->lookahead_token= token;
return WITH;
}
break;
default:
break;
}
return token;
}
int lex_one_token(void *arg, void *yythd)
{
reg1 uchar c= 0;
bool comment_closed;
int tokval, result_state;
uint length;
enum my_lex_states state;
THD *thd= (THD *)yythd;
Lex_input_stream *lip= & thd->m_parser_state->m_lip;
LEX *lex= thd->lex;
YYSTYPE *yylval=(YYSTYPE*) arg;
CHARSET_INFO *cs= thd->charset();
uchar *state_map= cs->state_map;
uchar *ident_map= cs->ident_map;
lip->yylval=yylval; // The global state
lip->start_token();
state=lip->next_state;
lip->next_state=MY_LEX_OPERATOR_OR_IDENT;
for (;;)
{
switch (state) {
case MY_LEX_OPERATOR_OR_IDENT: // Next is operator or keyword
case MY_LEX_START: // Start of token
// Skip starting whitespace
while(state_map[c= lip->yyPeek()] == MY_LEX_SKIP)
{
if (c == '\n')
lip->yylineno++;
lip->yySkip();
}
/* Start of real token */
lip->restart_token();
c= lip->yyGet();
state= (enum my_lex_states) state_map[c];
break;
case MY_LEX_ESCAPE:
if (lip->yyGet() == 'N')
{ // Allow \N as shortcut for NULL
yylval->lex_str.str=(char*) "\\N";
yylval->lex_str.length=2;
return NULL_SYM;
}
case MY_LEX_CHAR: // Unknown or single char token
case MY_LEX_SKIP: // This should not happen
if (c == '-' && lip->yyPeek() == '-' &&
(my_isspace(cs,lip->yyPeekn(1)) ||
my_iscntrl(cs,lip->yyPeekn(1))))
{
state=MY_LEX_COMMENT;
break;
}
if (c != ')')
lip->next_state= MY_LEX_START; // Allow signed numbers
if (c == ',')
{
/*
Warning:
This is a work around, to make the "remember_name" rule in
sql/sql_yacc.yy work properly.
The problem is that, when parsing "select expr1, expr2",
the code generated by bison executes the *pre* action
remember_name (see select_item) *before* actually parsing the
first token of expr2.
*/
lip->restart_token();
}
else
{
/*
Check for a placeholder: it should not precede a possible identifier
because of binlogging: when a placeholder is replaced with
its value in a query for the binlog, the query must stay
grammatically correct.
*/
if (c == '?' && lip->stmt_prepare_mode && !ident_map[lip->yyPeek()])
return(PARAM_MARKER);
}
return((int) c);
case MY_LEX_IDENT_OR_NCHAR:
if (lip->yyPeek() != '\'')
{
state= MY_LEX_IDENT;
break;
}
/* Found N'string' */
lip->yySkip(); // Skip '
if (!(yylval->lex_str.str = get_text(lip, 2, 1)))
{
state= MY_LEX_CHAR; // Read char by char
break;
}
yylval->lex_str.length= lip->yytoklen;
lex->text_string_is_7bit= (lip->tok_bitmap & 0x80) ? 0 : 1;
return(NCHAR_STRING);
case MY_LEX_IDENT_OR_HEX:
if (lip->yyPeek() == '\'')
{ // Found x'hex-number'
state= MY_LEX_HEX_NUMBER;
break;
}
case MY_LEX_IDENT_OR_BIN:
if (lip->yyPeek() == '\'')
{ // Found b'bin-number'
state= MY_LEX_BIN_NUMBER;
break;
}
case MY_LEX_IDENT:
const char *start;
#if defined(USE_MB) && defined(USE_MB_IDENT)
if (use_mb(cs))
{
result_state= IDENT_QUOTED;
if (my_mbcharlen(cs, lip->yyGetLast()) > 1)
{
int l = my_ismbchar(cs,
lip->get_ptr() -1,
lip->get_end_of_query());
if (l == 0) {
state = MY_LEX_CHAR;
continue;
}
lip->skip_binary(l - 1);
}
while (ident_map[c=lip->yyGet()])
{
if (my_mbcharlen(cs, c) > 1)
{
int l;
if ((l = my_ismbchar(cs,
lip->get_ptr() -1,
lip->get_end_of_query())) == 0)
break;
lip->skip_binary(l-1);
}
}
}
else
#endif
{
for (result_state= c; ident_map[c= lip->yyGet()]; result_state|= c) ;
/* If there were non-ASCII characters, mark that we must convert */
result_state= result_state & 0x80 ? IDENT_QUOTED : IDENT;
}
length= lip->yyLength();
start= lip->get_ptr();
if (lip->ignore_space)
{
/*
If we find a space then this can't be an identifier. We notice this
below by checking start != lex->ptr.
*/
for (; state_map[c] == MY_LEX_SKIP ; c= lip->yyGet()) ;
}
if (start == lip->get_ptr() && c == '.' && ident_map[lip->yyPeek()])
lip->next_state=MY_LEX_IDENT_SEP;
else
{ // '(' must follow directly if function
lip->yyUnget();
if ((tokval = find_keyword(lip, length, c == '(')))
{
lip->next_state= MY_LEX_START; // Allow signed numbers
return(tokval); // Was keyword
}
lip->yySkip(); // next state does a unget
}
yylval->lex_str=get_token(lip, 0, length);
/*
Note: "SELECT _bla AS 'alias'"
_bla should be considered as a IDENT if charset haven't been found.
So we don't use MYF(MY_WME) with get_charset_by_csname to avoid
producing an error.
*/
if (yylval->lex_str.str[0] == '_')
{
CHARSET_INFO *cs= get_charset_by_csname(yylval->lex_str.str + 1,
MY_CS_PRIMARY, MYF(0));
if (cs)
{
yylval->charset= cs;
lip->m_underscore_cs= cs;
lip->body_utf8_append(lip->m_cpp_text_start,
lip->get_cpp_tok_start() + length);
return(UNDERSCORE_CHARSET);
}
}
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_literal(thd, &yylval->lex_str, cs,
lip->m_cpp_text_end);
return(result_state); // IDENT or IDENT_QUOTED
case MY_LEX_IDENT_SEP: // Found ident and now '.'
yylval->lex_str.str= (char*) lip->get_ptr();
yylval->lex_str.length= 1;
c= lip->yyGet(); // should be '.'
lip->next_state= MY_LEX_IDENT_START;// Next is an ident (not a keyword)
if (!ident_map[lip->yyPeek()]) // Probably ` or "
lip->next_state= MY_LEX_START;
return((int) c);
case MY_LEX_NUMBER_IDENT: // number or ident which num-start
if (lip->yyGetLast() == '0')
{
c= lip->yyGet();
if (c == 'x')
{
while (my_isxdigit(cs,(c = lip->yyGet()))) ;
if ((lip->yyLength() >= 3) && !ident_map[c])
{
/* skip '0x' */
yylval->lex_str=get_token(lip, 2, lip->yyLength()-2);
return (HEX_NUM);
}
lip->yyUnget();
state= MY_LEX_IDENT_START;
break;
}
else if (c == 'b')
{
while ((c= lip->yyGet()) == '0' || c == '1') ;
if ((lip->yyLength() >= 3) && !ident_map[c])
{
/* Skip '0b' */
yylval->lex_str= get_token(lip, 2, lip->yyLength()-2);
return (BIN_NUM);
}
lip->yyUnget();
state= MY_LEX_IDENT_START;
break;
}
lip->yyUnget();
}
while (my_isdigit(cs, (c = lip->yyGet()))) ;
if (!ident_map[c])
{ // Can't be identifier
state=MY_LEX_INT_OR_REAL;
break;
}
if (c == 'e' || c == 'E')
{
// The following test is written this way to allow numbers of type 1e1
if (my_isdigit(cs,lip->yyPeek()) ||
(c=(lip->yyGet())) == '+' || c == '-')
{ // Allow 1E+10
if (my_isdigit(cs,lip->yyPeek())) // Number must have digit after sign
{
lip->yySkip();
while (my_isdigit(cs,lip->yyGet())) ;
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(FLOAT_NUM);
}
}
lip->yyUnget();
}
// fall through
case MY_LEX_IDENT_START: // We come here after '.'
result_state= IDENT;
#if defined(USE_MB) && defined(USE_MB_IDENT)
if (use_mb(cs))
{
result_state= IDENT_QUOTED;
while (ident_map[c=lip->yyGet()])
{
if (my_mbcharlen(cs, c) > 1)
{
int l;
if ((l = my_ismbchar(cs,
lip->get_ptr() -1,
lip->get_end_of_query())) == 0)
break;
lip->skip_binary(l-1);
}
}
}
else
#endif
{
for (result_state=0; ident_map[c= lip->yyGet()]; result_state|= c) ;
/* If there were non-ASCII characters, mark that we must convert */
result_state= result_state & 0x80 ? IDENT_QUOTED : IDENT;
}
if (c == '.' && ident_map[lip->yyPeek()])
lip->next_state=MY_LEX_IDENT_SEP;// Next is '.'
yylval->lex_str= get_token(lip, 0, lip->yyLength());
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_literal(thd, &yylval->lex_str, cs,
lip->m_cpp_text_end);
return(result_state);
case MY_LEX_USER_VARIABLE_DELIMITER: // Found quote char
{
uint double_quotes= 0;
char quote_char= c; // Used char
while ((c=lip->yyGet()))
{
int var_length;
if ((var_length= my_mbcharlen(cs, c)) == 1)
{
if (c == quote_char)
{
if (lip->yyPeek() != quote_char)
break;
c=lip->yyGet();
double_quotes++;
continue;
}
}
#ifdef USE_MB
else if (use_mb(cs))
{
if ((var_length= my_ismbchar(cs, lip->get_ptr() - 1,
lip->get_end_of_query())))
lip->skip_binary(var_length-1);
}
#endif
}
if (double_quotes)
yylval->lex_str=get_quoted_token(lip, 1,
lip->yyLength() - double_quotes -1,
quote_char);
else
yylval->lex_str=get_token(lip, 1, lip->yyLength() -1);
if (c == quote_char)
lip->yySkip(); // Skip end `
lip->next_state= MY_LEX_START;
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_literal(thd, &yylval->lex_str, cs,
lip->m_cpp_text_end);
return(IDENT_QUOTED);
}
case MY_LEX_INT_OR_REAL: // Complete int or incomplete real
if (c != '.')
{ // Found complete integer number.
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return int_token(yylval->lex_str.str, (uint) yylval->lex_str.length);
}
// fall through
case MY_LEX_REAL: // Incomplete real number
while (my_isdigit(cs,c = lip->yyGet())) ;
if (c == 'e' || c == 'E')
{
c = lip->yyGet();
if (c == '-' || c == '+')
c = lip->yyGet(); // Skip sign
if (!my_isdigit(cs,c))
{ // No digit after sign
state= MY_LEX_CHAR;
break;
}
while (my_isdigit(cs,lip->yyGet())) ;
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(FLOAT_NUM);
}
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(DECIMAL_NUM);
case MY_LEX_HEX_NUMBER: // Found x'hexstring'
lip->yySkip(); // Accept opening '
while (my_isxdigit(cs, (c= lip->yyGet()))) ;
if (c != '\'')
return(ABORT_SYM); // Illegal hex constant
lip->yySkip(); // Accept closing '
length= lip->yyLength(); // Length of hexnum+3
if ((length % 2) == 0)
return(ABORT_SYM); // odd number of hex digits
yylval->lex_str=get_token(lip,
2, // skip x'
length-3); // don't count x' and last '
return (HEX_NUM);
case MY_LEX_BIN_NUMBER: // Found b'bin-string'
lip->yySkip(); // Accept opening '
while ((c= lip->yyGet()) == '0' || c == '1') ;
if (c != '\'')
return(ABORT_SYM); // Illegal hex constant
lip->yySkip(); // Accept closing '
length= lip->yyLength(); // Length of bin-num + 3
yylval->lex_str= get_token(lip,
2, // skip b'
length-3); // don't count b' and last '
return (BIN_NUM);
case MY_LEX_CMP_OP: // Incomplete comparison operator
if (state_map[lip->yyPeek()] == MY_LEX_CMP_OP ||
state_map[lip->yyPeek()] == MY_LEX_LONG_CMP_OP)
lip->yySkip();
if ((tokval = find_keyword(lip, lip->yyLength() + 1, 0)))
{
lip->next_state= MY_LEX_START; // Allow signed numbers
return(tokval);
}
state = MY_LEX_CHAR; // Something fishy found
break;
case MY_LEX_LONG_CMP_OP: // Incomplete comparison operator
if (state_map[lip->yyPeek()] == MY_LEX_CMP_OP ||
state_map[lip->yyPeek()] == MY_LEX_LONG_CMP_OP)
{
lip->yySkip();
if (state_map[lip->yyPeek()] == MY_LEX_CMP_OP)
lip->yySkip();
}
if ((tokval = find_keyword(lip, lip->yyLength() + 1, 0)))
{
lip->next_state= MY_LEX_START; // Found long op
return(tokval);
}
state = MY_LEX_CHAR; // Something fishy found
break;
case MY_LEX_BOOL:
if (c != lip->yyPeek())
{
state=MY_LEX_CHAR;
break;
}
lip->yySkip();
tokval = find_keyword(lip,2,0); // Is a bool operator
lip->next_state= MY_LEX_START; // Allow signed numbers
return(tokval);
case MY_LEX_STRING_OR_DELIMITER:
if (thd->variables.sql_mode & MODE_ANSI_QUOTES)
{
state= MY_LEX_USER_VARIABLE_DELIMITER;
break;
}
/* " used for strings */
case MY_LEX_STRING: // Incomplete text string
if (!(yylval->lex_str.str = get_text(lip, 1, 1)))
{
state= MY_LEX_CHAR; // Read char by char
break;
}
yylval->lex_str.length=lip->yytoklen;
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_literal(thd, &yylval->lex_str,
lip->m_underscore_cs ? lip->m_underscore_cs : cs,
lip->m_cpp_text_end);
lip->m_underscore_cs= NULL;
lex->text_string_is_7bit= (lip->tok_bitmap & 0x80) ? 0 : 1;
return(TEXT_STRING);
case MY_LEX_COMMENT: // Comment
lex->select_lex.options|= OPTION_FOUND_COMMENT;
while ((c = lip->yyGet()) != '\n' && c) ;
lip->yyUnget(); // Safety against eof
state = MY_LEX_START; // Try again
break;
case MY_LEX_LONG_COMMENT: /* Long C comment? */
if (lip->yyPeek() != '*')
{
state=MY_LEX_CHAR; // Probable division
break;
}
lex->select_lex.options|= OPTION_FOUND_COMMENT;
/* Reject '/' '*', since we might need to turn off the echo */
lip->yyUnget();
lip->save_in_comment_state();
if (lip->yyPeekn(2) == '!')
{
lip->in_comment= DISCARD_COMMENT;
/* Accept '/' '*' '!', but do not keep this marker. */
lip->set_echo(FALSE);
lip->yySkip();
lip->yySkip();
lip->yySkip();
/*
The special comment format is very strict:
'/' '*' '!', followed by exactly
1 digit (major), 2 digits (minor), then 2 digits (dot).
32302 -> 3.23.02
50032 -> 5.0.32
50114 -> 5.1.14
*/
char version_str[6];
version_str[0]= lip->yyPeekn(0);
version_str[1]= lip->yyPeekn(1);
version_str[2]= lip->yyPeekn(2);
version_str[3]= lip->yyPeekn(3);
version_str[4]= lip->yyPeekn(4);
version_str[5]= 0;
if ( my_isdigit(cs, version_str[0])
&& my_isdigit(cs, version_str[1])
&& my_isdigit(cs, version_str[2])
&& my_isdigit(cs, version_str[3])
&& my_isdigit(cs, version_str[4])
)
{
ulong version;
version=strtol(version_str, NULL, 10);
if (version <= MYSQL_VERSION_ID)
{
/* Accept 'M' 'm' 'm' 'd' 'd' */
lip->yySkipn(5);
/* Expand the content of the special comment as real code */
lip->set_echo(TRUE);
state=MY_LEX_START;
break; /* Do not treat contents as a comment. */
}
else
{
/*
Patch and skip the conditional comment to avoid it
being propagated infinitely (eg. to a slave).
*/
char *pcom= lip->yyUnput(' ');
comment_closed= ! consume_comment(lip, 1);
if (! comment_closed)
{
*pcom= '!';
}
/* version allowed to have one level of comment inside. */
}
}
else
{
/* Not a version comment. */
state=MY_LEX_START;
lip->set_echo(TRUE);
break;
}
}
else
{
lip->in_comment= PRESERVE_COMMENT;
lip->yySkip(); // Accept /
lip->yySkip(); // Accept *
comment_closed= ! consume_comment(lip, 0);
/* regular comments can have zero comments inside. */
}
/*
Discard:
- regular '/' '*' comments,
- special comments '/' '*' '!' for a future version,
by scanning until we find a closing '*' '/' marker.
Nesting regular comments isn't allowed. The first
'*' '/' returns the parser to the previous state.
/#!VERSI oned containing /# regular #/ is allowed #/
Inside one versioned comment, another versioned comment
is treated as a regular discardable comment. It gets
no special parsing.
*/
/* Unbalanced comments with a missing '*' '/' are a syntax error */
if (! comment_closed)
return (ABORT_SYM);
state = MY_LEX_START; // Try again
lip->restore_in_comment_state();
break;
case MY_LEX_END_LONG_COMMENT:
if ((lip->in_comment != NO_COMMENT) && lip->yyPeek() == '/')
{
/* Reject '*' '/' */
lip->yyUnget();
/* Accept '*' '/', with the proper echo */
lip->set_echo(lip->in_comment == PRESERVE_COMMENT);
lip->yySkipn(2);
/* And start recording the tokens again */
lip->set_echo(TRUE);
lip->in_comment=NO_COMMENT;
state=MY_LEX_START;
}
else
state=MY_LEX_CHAR; // Return '*'
break;
case MY_LEX_SET_VAR: // Check if ':='
if (lip->yyPeek() != '=')
{
state=MY_LEX_CHAR; // Return ':'
break;
}
lip->yySkip();
return (SET_VAR);
case MY_LEX_SEMICOLON: // optional line terminator
state= MY_LEX_CHAR; // Return ';'
break;
case MY_LEX_EOL:
if (lip->eof())
{
lip->yyUnget(); // Reject the last '\0'
lip->set_echo(FALSE);
lip->yySkip();
lip->set_echo(TRUE);
/* Unbalanced comments with a missing '*' '/' are a syntax error */
if (lip->in_comment != NO_COMMENT)
return (ABORT_SYM);
lip->next_state=MY_LEX_END; // Mark for next loop
return(END_OF_INPUT);
}
state=MY_LEX_CHAR;
break;
case MY_LEX_END:
lip->next_state=MY_LEX_END;
return(0); // We found end of input last time
/* Actually real shouldn't start with . but allow them anyhow */
case MY_LEX_REAL_OR_POINT:
if (my_isdigit(cs,lip->yyPeek()))
state = MY_LEX_REAL; // Real
else
{
state= MY_LEX_IDENT_SEP; // return '.'
lip->yyUnget(); // Put back '.'
}
break;
case MY_LEX_USER_END: // end '@' of user@hostname
switch (state_map[lip->yyPeek()]) {
case MY_LEX_STRING:
case MY_LEX_USER_VARIABLE_DELIMITER:
case MY_LEX_STRING_OR_DELIMITER:
break;
case MY_LEX_USER_END:
lip->next_state=MY_LEX_SYSTEM_VAR;
break;
default:
lip->next_state=MY_LEX_HOSTNAME;
break;
}
yylval->lex_str.str=(char*) lip->get_ptr();
yylval->lex_str.length=1;
return((int) '@');
case MY_LEX_HOSTNAME: // end '@' of user@hostname
for (c=lip->yyGet() ;
my_isalnum(cs,c) || c == '.' || c == '_' || c == '$';
c= lip->yyGet()) ;
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(LEX_HOSTNAME);
case MY_LEX_SYSTEM_VAR:
yylval->lex_str.str=(char*) lip->get_ptr();
yylval->lex_str.length=1;
lip->yySkip(); // Skip '@'
lip->next_state= (state_map[lip->yyPeek()] ==
MY_LEX_USER_VARIABLE_DELIMITER ?
MY_LEX_OPERATOR_OR_IDENT :
MY_LEX_IDENT_OR_KEYWORD);
return((int) '@');
case MY_LEX_IDENT_OR_KEYWORD:
/*
We come here when we have found two '@' in a row.
We should now be able to handle:
[(global | local | session) .]variable_name
*/
for (result_state= 0; ident_map[c= lip->yyGet()]; result_state|= c) ;
/* If there were non-ASCII characters, mark that we must convert */
result_state= result_state & 0x80 ? IDENT_QUOTED : IDENT;
if (c == '.')
lip->next_state=MY_LEX_IDENT_SEP;
length= lip->yyLength();
if (length == 0)
return(ABORT_SYM); // Names must be nonempty.
if ((tokval= find_keyword(lip, length,0)))
{
lip->yyUnget(); // Put back 'c'
return(tokval); // Was keyword
}
yylval->lex_str=get_token(lip, 0, length);
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_literal(thd, &yylval->lex_str, cs,
lip->m_cpp_text_end);
return(result_state);
}
}
}
/**
Construct a copy of this object to be used for mysql_alter_table
and mysql_create_table.
Historically, these two functions modify their Alter_info
arguments. This behaviour breaks re-execution of prepared
statements and stored procedures and is compensated by always
supplying a copy of Alter_info to these functions.
@return You need to use check the error in THD for out
of memory condition after calling this function.
*/
Alter_info::Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root)
:drop_list(rhs.drop_list, mem_root),
alter_list(rhs.alter_list, mem_root),
key_list(rhs.key_list, mem_root),
create_list(rhs.create_list, mem_root),
flags(rhs.flags),
keys_onoff(rhs.keys_onoff),
tablespace_op(rhs.tablespace_op),
partition_names(rhs.partition_names, mem_root),
num_parts(rhs.num_parts),
change_level(rhs.change_level),
datetime_field(rhs.datetime_field),
error_if_not_empty(rhs.error_if_not_empty)
{
/*
Make deep copies of used objects.
This is not a fully deep copy - clone() implementations
of Alter_drop, Alter_column, Key, foreign_key, Key_part_spec
do not copy string constants. At the same length the only
reason we make a copy currently is that ALTER/CREATE TABLE
code changes input Alter_info definitions, but string
constants never change.
*/
list_copy_and_replace_each_value(drop_list, mem_root);
list_copy_and_replace_each_value(alter_list, mem_root);
list_copy_and_replace_each_value(key_list, mem_root);
list_copy_and_replace_each_value(create_list, mem_root);
/* partition_names are not deeply copied currently */
}
void trim_whitespace(CHARSET_INFO *cs, LEX_STRING *str)
{
/*
TODO:
This code assumes that there are no multi-bytes characters
that can be considered white-space.
*/
while ((str->length > 0) && (my_isspace(cs, str->str[0])))
{
str->length --;
str->str ++;
}
/*
FIXME:
Also, parsing backward is not safe with multi bytes characters
*/
while ((str->length > 0) && (my_isspace(cs, str->str[str->length-1])))
{
str->length --;
}
}
/*
st_select_lex structures initialisations
*/
void st_select_lex_node::init_query()
{
options= 0;
sql_cache= SQL_CACHE_UNSPECIFIED;
linkage= UNSPECIFIED_TYPE;
no_error= no_table_names_allowed= 0;
uncacheable= 0;
}
void st_select_lex_node::init_select()
{
}
void st_select_lex_unit::init_query()
{
st_select_lex_node::init_query();
linkage= GLOBAL_OPTIONS_TYPE;
global_parameters= first_select();
select_limit_cnt= HA_POS_ERROR;
offset_limit_cnt= 0;
union_distinct= 0;
prepared= optimized= executed= 0;
item= 0;
union_result= 0;
table= 0;
fake_select_lex= 0;
cleaned= 0;
item_list.empty();
describe= 0;
found_rows_for_union= 0;
}
void st_select_lex::init_query()
{
st_select_lex_node::init_query();
table_list.empty();
top_join_list.empty();
join_list= &top_join_list;
embedding= leaf_tables= 0;
item_list.empty();
join= 0;
having= prep_having= where= prep_where= 0;
olap= UNSPECIFIED_OLAP_TYPE;
having_fix_field= 0;
group_fix_field= 0;
context.select_lex= this;
context.init();
/*
Add the name resolution context of the current (sub)query to the
stack of contexts for the whole query.
TODO:
push_context may return an error if there is no memory for a new
element in the stack, however this method has no return value,
thus push_context should be moved to a place where query
initialization is checked for failure.
*/
parent_lex->push_context(&context);
cond_count= between_count= with_wild= 0;
max_equal_elems= 0;
ref_pointer_array= 0;
select_n_where_fields= 0;
select_n_having_items= 0;
subquery_in_having= explicit_limit= 0;
is_item_list_lookup= 0;
first_execution= 1;
first_natural_join_processing= 1;
first_cond_optimization= 1;
parsing_place= NO_MATTER;
exclude_from_table_unique_test= no_wrap_view_item= FALSE;
nest_level= 0;
link_next= 0;
}
void st_select_lex::init_select()
{
st_select_lex_node::init_select();
group_list.empty();
type= db= 0;
having= 0;
table_join_options= 0;
in_sum_expr= with_wild= 0;
options= 0;
sql_cache= SQL_CACHE_UNSPECIFIED;
braces= 0;
interval_list.empty();
ftfunc_list_alloc.empty();
inner_sum_func_list= 0;
ftfunc_list= &ftfunc_list_alloc;
linkage= UNSPECIFIED_TYPE;
order_list.elements= 0;
order_list.first= 0;
order_list.next= &order_list.first;
/* Set limit and offset to default values */
select_limit= 0; /* denotes the default limit = HA_POS_ERROR */
offset_limit= 0; /* denotes the default offset = 0 */
with_sum_func= 0;
is_correlated= 0;
cur_pos_in_select_list= UNDEF_POS;
non_agg_fields.empty();
cond_value= having_value= Item::COND_UNDEF;
inner_refs_list.empty();
full_group_by_flag= 0;
}
/*
st_select_lex structures linking
*/
/* include on level down */
void st_select_lex_node::include_down(st_select_lex_node *upper)
{
if ((next= upper->slave))
next->prev= &next;
prev= &upper->slave;
upper->slave= this;
master= upper;
slave= 0;
}
/*
include on level down (but do not link)
SYNOPSYS
st_select_lex_node::include_standalone()
upper - reference on node underr which this node should be included
ref - references on reference on this node
*/
void st_select_lex_node::include_standalone(st_select_lex_node *upper,
st_select_lex_node **ref)
{
next= 0;
prev= ref;
master= upper;
slave= 0;
}
/* include neighbour (on same level) */
void st_select_lex_node::include_neighbour(st_select_lex_node *before)
{
if ((next= before->next))
next->prev= &next;
prev= &before->next;
before->next= this;
master= before->master;
slave= 0;
}
/* including in global SELECT_LEX list */
void st_select_lex_node::include_global(st_select_lex_node **plink)
{
if ((link_next= *plink))
link_next->link_prev= &link_next;
link_prev= plink;
*plink= this;
}
//excluding from global list (internal function)
void st_select_lex_node::fast_exclude()
{
if (link_prev)
{
if ((*link_prev= link_next))
link_next->link_prev= link_prev;
}
// Remove slave structure
for (; slave; slave= slave->next)
slave->fast_exclude();
}
/*
excluding select_lex structure (except first (first select can't be
deleted, because it is most upper select))
*/
void st_select_lex_node::exclude()
{
//exclude from global list
fast_exclude();
//exclude from other structures
if ((*prev= next))
next->prev= prev;
/*
We do not need following statements, because prev pointer of first
list element point to master->slave
if (master->slave == this)
master->slave= next;
*/
}
/*
Exclude level of current unit from tree of SELECTs
SYNOPSYS
st_select_lex_unit::exclude_level()
NOTE: units which belong to current will be brought up on level of
currernt unit
*/
void st_select_lex_unit::exclude_level()
{
SELECT_LEX_UNIT *units= 0, **units_last= &units;
for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
{
// unlink current level from global SELECTs list
if (sl->link_prev && (*sl->link_prev= sl->link_next))
sl->link_next->link_prev= sl->link_prev;
// bring up underlay levels
SELECT_LEX_UNIT **last= 0;
for (SELECT_LEX_UNIT *u= sl->first_inner_unit(); u; u= u->next_unit())
{
u->master= master;
last= (SELECT_LEX_UNIT**)&(u->next);
}
if (last)
{
(*units_last)= sl->first_inner_unit();
units_last= last;
}
}
if (units)
{
// include brought up levels in place of current
(*prev)= units;
(*units_last)= (SELECT_LEX_UNIT*)next;
if (next)
next->prev= (SELECT_LEX_NODE**)units_last;
units->prev= prev;
}
else
{
// exclude currect unit from list of nodes
(*prev)= next;
if (next)
next->prev= prev;
}
}
/*
Exclude subtree of current unit from tree of SELECTs
SYNOPSYS
st_select_lex_unit::exclude_tree()
*/
void st_select_lex_unit::exclude_tree()
{
for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
{
// unlink current level from global SELECTs list
if (sl->link_prev && (*sl->link_prev= sl->link_next))
sl->link_next->link_prev= sl->link_prev;
// unlink underlay levels
for (SELECT_LEX_UNIT *u= sl->first_inner_unit(); u; u= u->next_unit())
{
u->exclude_level();
}
}
// exclude currect unit from list of nodes
(*prev)= next;
if (next)
next->prev= prev;
}
/*
st_select_lex_node::mark_as_dependent mark all st_select_lex struct from
this to 'last' as dependent
SYNOPSIS
last - pointer to last st_select_lex struct, before wich all
st_select_lex have to be marked as dependent
NOTE
'last' should be reachable from this st_select_lex_node
*/
void st_select_lex::mark_as_dependent(st_select_lex *last)
{
/*
Mark all selects from resolved to 1 before select where was
found table as depended (of select where was found table)
*/
for (SELECT_LEX *s= this;
s && s != last;
s= s->outer_select())
if (!(s->uncacheable & UNCACHEABLE_DEPENDENT))
{
// Select is dependent of outer select
s->uncacheable= (s->uncacheable & ~UNCACHEABLE_UNITED) |
UNCACHEABLE_DEPENDENT;
SELECT_LEX_UNIT *munit= s->master_unit();
munit->uncacheable= (munit->uncacheable & ~UNCACHEABLE_UNITED) |
UNCACHEABLE_DEPENDENT;
for (SELECT_LEX *sl= munit->first_select(); sl ; sl= sl->next_select())
{
if (sl != s &&
!(sl->uncacheable & (UNCACHEABLE_DEPENDENT | UNCACHEABLE_UNITED)))
sl->uncacheable|= UNCACHEABLE_UNITED;
}
}
is_correlated= TRUE;
this->master_unit()->item->is_correlated= TRUE;
}
bool st_select_lex_node::set_braces(bool value) { return 1; }
bool st_select_lex_node::inc_in_sum_expr() { return 1; }
uint st_select_lex_node::get_in_sum_expr() { return 0; }
TABLE_LIST* st_select_lex_node::get_table_list() { return 0; }
List<Item>* st_select_lex_node::get_item_list() { return 0; }
TABLE_LIST *st_select_lex_node::add_table_to_list (THD *thd, Table_ident *table,
LEX_STRING *alias,
ulong table_join_options,
thr_lock_type flags,
enum_mdl_type mdl_type,
List<Index_hint> *hints,
LEX_STRING *option)
{
return 0;
}
ulong st_select_lex_node::get_table_join_options()
{
return 0;
}
/*
prohibit using LIMIT clause
*/
bool st_select_lex::test_limit()
{
if (select_limit != 0)
{
my_error(ER_NOT_SUPPORTED_YET, MYF(0),
"LIMIT & IN/ALL/ANY/SOME subquery");
return(1);
}
return(0);
}
st_select_lex_unit* st_select_lex_unit::master_unit()
{
return this;
}
st_select_lex* st_select_lex_unit::outer_select()
{
return (st_select_lex*) master;
}
bool st_select_lex::add_order_to_list(THD *thd, Item *item, bool asc)
{
return add_to_list(thd, order_list, item, asc);
}
bool st_select_lex::add_item_to_list(THD *thd, Item *item)
{
DBUG_ENTER("st_select_lex::add_item_to_list");
DBUG_PRINT("info", ("Item: 0x%lx", (long) item));
DBUG_RETURN(item_list.push_back(item));
}
bool st_select_lex::add_group_to_list(THD *thd, Item *item, bool asc)
{
return add_to_list(thd, group_list, item, asc);
}
bool st_select_lex::add_ftfunc_to_list(Item_func_match *func)
{
return !func || ftfunc_list->push_back(func); // end of memory?
}
st_select_lex_unit* st_select_lex::master_unit()
{
return (st_select_lex_unit*) master;
}
st_select_lex* st_select_lex::outer_select()
{
return (st_select_lex*) master->get_master();
}
bool st_select_lex::set_braces(bool value)
{
braces= value;
return 0;
}
bool st_select_lex::inc_in_sum_expr()
{
in_sum_expr++;
return 0;
}
uint st_select_lex::get_in_sum_expr()
{
return in_sum_expr;
}
TABLE_LIST* st_select_lex::get_table_list()
{
return table_list.first;
}
List<Item>* st_select_lex::get_item_list()
{
return &item_list;
}
ulong st_select_lex::get_table_join_options()
{
return table_join_options;
}
bool st_select_lex::setup_ref_array(THD *thd, uint order_group_num)
{
if (ref_pointer_array)
return 0;
/*
We have to create array in prepared statement memory if it is
prepared statement
*/
Query_arena *arena= thd->stmt_arena;
return (ref_pointer_array=
(Item **)arena->alloc(sizeof(Item*) * (n_child_sum_items +
item_list.elements +
select_n_having_items +
select_n_where_fields +
order_group_num)*5)) == 0;
}
void st_select_lex_unit::print(String *str, enum_query_type query_type)
{
bool union_all= !union_distinct;
for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
{
if (sl != first_select())
{
str->append(STRING_WITH_LEN(" union "));
if (union_all)
str->append(STRING_WITH_LEN("all "));
else if (union_distinct == sl)
union_all= TRUE;
}
if (sl->braces)
str->append('(');
sl->print(thd, str, query_type);
if (sl->braces)
str->append(')');
}
if (fake_select_lex == global_parameters)
{
if (fake_select_lex->order_list.elements)
{
str->append(STRING_WITH_LEN(" order by "));
fake_select_lex->print_order(str,
fake_select_lex->order_list.first,
query_type);
}
fake_select_lex->print_limit(thd, str, query_type);
}
}
void st_select_lex::print_order(String *str,
ORDER *order,
enum_query_type query_type)
{
for (; order; order= order->next)
{
if (order->counter_used)
{
char buffer[20];
size_t length= my_snprintf(buffer, 20, "%d", order->counter);
str->append(buffer, (uint) length);
}
else
(*order->item)->print(str, query_type);
if (!order->asc)
str->append(STRING_WITH_LEN(" desc"));
if (order->next)
str->append(',');
}
}
void st_select_lex::print_limit(THD *thd,
String *str,
enum_query_type query_type)
{
SELECT_LEX_UNIT *unit= master_unit();
Item_subselect *item= unit->item;
if (item && unit->global_parameters == this &&
(item->substype() == Item_subselect::EXISTS_SUBS ||
item->substype() == Item_subselect::IN_SUBS ||
item->substype() == Item_subselect::ALL_SUBS))
{
DBUG_ASSERT(!item->fixed ||
(select_limit->val_int() == LL(1) && offset_limit == 0));
return;
}
if (explicit_limit)
{
str->append(STRING_WITH_LEN(" limit "));
if (offset_limit)
{
offset_limit->print(str, query_type);
str->append(',');
}
select_limit->print(str, query_type);
}
}
/**
@brief Restore the LEX and THD in case of a parse error.
This is a clean up call that is invoked by the Bison generated
parser before returning an error from MYSQLparse. If your
semantic actions manipulate with the global thread state (which
is a very bad practice and should not normally be employed) and
need a clean-up in case of error, and you can not use %destructor
rule in the grammar file itself, this function should be used
to implement the clean up.
*/
void LEX::cleanup_lex_after_parse_error(THD *thd)
{
/*
Delete sphead for the side effect of restoring of the original
LEX state, thd->lex, thd->mem_root and thd->free_list if they
were replaced when parsing stored procedure statements. We
will never use sphead object after a parse error, so it's okay
to delete it only for the sake of the side effect.
TODO: make this functionality explicit in sp_head class.
Sic: we must nullify the member of the main lex, not the
current one that will be thrown away
*/
if (thd->lex->sphead)
{
thd->lex->sphead->restore_thd_mem_root(thd);
delete thd->lex->sphead;
thd->lex->sphead= NULL;
}
}
/*
Initialize (or reset) Query_tables_list object.
SYNOPSIS
reset_query_tables_list()
init TRUE - we should perform full initialization of object with
allocating needed memory
FALSE - object is already initialized so we should only reset
its state so it can be used for parsing/processing
of new statement
DESCRIPTION
This method initializes Query_tables_list so it can be used as part
of LEX object for parsing/processing of statement. One can also use
this method to reset state of already initialized Query_tables_list
so it can be used for processing of new statement.
*/
void Query_tables_list::reset_query_tables_list(bool init)
{
sql_command= SQLCOM_END;
if (!init && query_tables)
{
TABLE_LIST *table= query_tables;
for (;;)
{
delete table->view;
if (query_tables_last == &table->next_global ||
!(table= table->next_global))
break;
}
}
query_tables= 0;
query_tables_last= &query_tables;
query_tables_own_last= 0;
if (init)
{
/*
We delay real initialization of hash (and therefore related
memory allocation) until first insertion into this hash.
*/
my_hash_clear(&sroutines);
}
else if (sroutines.records)
{
/* Non-zero sroutines.records means that hash was initialized. */
my_hash_reset(&sroutines);
}
sroutines_list.empty();
sroutines_list_own_last= sroutines_list.next;
sroutines_list_own_elements= 0;
binlog_stmt_flags= 0;
stmt_accessed_table_flag= 0;
}
/*
Destroy Query_tables_list object with freeing all resources used by it.
SYNOPSIS
destroy_query_tables_list()
*/
void Query_tables_list::destroy_query_tables_list()
{
my_hash_free(&sroutines);
}
/*
Initialize LEX object.
SYNOPSIS
LEX::LEX()
NOTE
LEX object initialized with this constructor can be used as part of
THD object for which one can safely call open_tables(), lock_tables()
and close_thread_tables() functions. But it is not yet ready for
statement parsing. On should use lex_start() function to prepare LEX
for this.
*/
LEX::LEX()
:result(0), option_type(OPT_DEFAULT), is_lex_started(0)
{
my_init_dynamic_array2(&plugins, sizeof(plugin_ref),
plugins_static_buffer,
INITIAL_LEX_PLUGIN_LIST_SIZE,
INITIAL_LEX_PLUGIN_LIST_SIZE);
reset_query_tables_list(TRUE);
}
/*
Check whether the merging algorithm can be used on this VIEW
SYNOPSIS
LEX::can_be_merged()
DESCRIPTION
We can apply merge algorithm if it is single SELECT view with
subqueries only in WHERE clause (we do not count SELECTs of underlying
views, and second level subqueries) and we have not grpouping, ordering,
HAVING clause, aggregate functions, DISTINCT clause, LIMIT clause and
several underlying tables.
RETURN
FALSE - only temporary table algorithm can be used
TRUE - merge algorithm can be used
*/
bool LEX::can_be_merged()
{
// TODO: do not forget implement case when select_lex.table_list.elements==0
/* find non VIEW subqueries/unions */
bool selects_allow_merge= select_lex.next_select() == 0;
if (selects_allow_merge)
{
for (SELECT_LEX_UNIT *tmp_unit= select_lex.first_inner_unit();
tmp_unit;
tmp_unit= tmp_unit->next_unit())
{
if (tmp_unit->first_select()->parent_lex == this &&
(tmp_unit->item == 0 ||
(tmp_unit->item->place() != IN_WHERE &&
tmp_unit->item->place() != IN_ON)))
{
selects_allow_merge= 0;
break;
}
}
}
return (selects_allow_merge &&
select_lex.group_list.elements == 0 &&
select_lex.having == 0 &&
select_lex.with_sum_func == 0 &&
select_lex.table_list.elements >= 1 &&
!(select_lex.options & SELECT_DISTINCT) &&
select_lex.select_limit == 0);
}
/*
check if command can use VIEW with MERGE algorithm (for top VIEWs)
SYNOPSIS
LEX::can_use_merged()
DESCRIPTION
Only listed here commands can use merge algorithm in top level
SELECT_LEX (for subqueries will be used merge algorithm if
LEX::can_not_use_merged() is not TRUE).
RETURN
FALSE - command can't use merged VIEWs
TRUE - VIEWs with MERGE algorithms can be used
*/
bool LEX::can_use_merged()
{
switch (sql_command)
{
case SQLCOM_SELECT:
case SQLCOM_CREATE_TABLE:
case SQLCOM_UPDATE:
case SQLCOM_UPDATE_MULTI:
case SQLCOM_DELETE:
case SQLCOM_DELETE_MULTI:
case SQLCOM_INSERT:
case SQLCOM_INSERT_SELECT:
case SQLCOM_REPLACE:
case SQLCOM_REPLACE_SELECT:
case SQLCOM_LOAD:
return TRUE;
default:
return FALSE;
}
}
/*
Check if command can't use merged views in any part of command
SYNOPSIS
LEX::can_not_use_merged()
DESCRIPTION
Temporary table algorithm will be used on all SELECT levels for queries
listed here (see also LEX::can_use_merged()).
RETURN
FALSE - command can't use merged VIEWs
TRUE - VIEWs with MERGE algorithms can be used
*/
bool LEX::can_not_use_merged()
{
switch (sql_command)
{
case SQLCOM_CREATE_VIEW:
case SQLCOM_SHOW_CREATE:
/*
SQLCOM_SHOW_FIELDS is necessary to make
information schema tables working correctly with views.
see get_schema_tables_result function
*/
case SQLCOM_SHOW_FIELDS:
return TRUE;
default:
return FALSE;
}
}
/*
Detect that we need only table structure of derived table/view
SYNOPSIS
only_view_structure()
RETURN
TRUE yes, we need only structure
FALSE no, we need data
*/
bool LEX::only_view_structure()
{
switch (sql_command) {
case SQLCOM_SHOW_CREATE:
case SQLCOM_SHOW_TABLES:
case SQLCOM_SHOW_FIELDS:
case SQLCOM_REVOKE_ALL:
case SQLCOM_REVOKE:
case SQLCOM_GRANT:
case SQLCOM_CREATE_VIEW:
return TRUE;
default:
return FALSE;
}
}
/*
Should Items_ident be printed correctly
SYNOPSIS
need_correct_ident()
RETURN
TRUE yes, we need only structure
FALSE no, we need data
*/
bool LEX::need_correct_ident()
{
switch(sql_command)
{
case SQLCOM_SHOW_CREATE:
case SQLCOM_SHOW_TABLES:
case SQLCOM_CREATE_VIEW:
return TRUE;
default:
return FALSE;
}
}
/*
Get effective type of CHECK OPTION for given view
SYNOPSIS
get_effective_with_check()
view given view
NOTE
It have not sense to set CHECK OPTION for SELECT satement or subqueries,
so we do not.
RETURN
VIEW_CHECK_NONE no need CHECK OPTION
VIEW_CHECK_LOCAL CHECK OPTION LOCAL
VIEW_CHECK_CASCADED CHECK OPTION CASCADED
*/
uint8 LEX::get_effective_with_check(TABLE_LIST *view)
{
if (view->select_lex->master_unit() == &unit &&
which_check_option_applicable())
return (uint8)view->with_check;
return VIEW_CHECK_NONE;
}
/**
This method should be called only during parsing.
It is aware of compound statements (stored routine bodies)
and will initialize the destination with the default
database of the stored routine, rather than the default
database of the connection it is parsed in.
E.g. if one has no current database selected, or current database
set to 'bar' and then issues:
CREATE PROCEDURE foo.p1() BEGIN SELECT * FROM t1 END//
t1 is meant to refer to foo.t1, not to bar.t1.
This method is needed to support this rule.
@return TRUE in case of error (parsing should be aborted, FALSE in
case of success
*/
bool
LEX::copy_db_to(char **p_db, size_t *p_db_length) const
{
if (sphead)
{
DBUG_ASSERT(sphead->m_db.str && sphead->m_db.length);
/*
It is safe to assign the string by-pointer, both sphead and
its statements reside in the same memory root.
*/
*p_db= sphead->m_db.str;
if (p_db_length)
*p_db_length= sphead->m_db.length;
return FALSE;
}
return thd->copy_db_to(p_db, p_db_length);
}
/*
initialize limit counters
SYNOPSIS
st_select_lex_unit::set_limit()
values - SELECT_LEX with initial values for counters
*/
void st_select_lex_unit::set_limit(st_select_lex *sl)
{
ha_rows select_limit_val;
ulonglong val;
DBUG_ASSERT(! thd->stmt_arena->is_stmt_prepare());
val= sl->select_limit ? sl->select_limit->val_uint() : HA_POS_ERROR;
select_limit_val= (ha_rows)val;
#ifndef BIG_TABLES
/*
Check for overflow : ha_rows can be smaller then ulonglong if
BIG_TABLES is off.
*/
if (val != (ulonglong)select_limit_val)
select_limit_val= HA_POS_ERROR;
#endif
val= sl->offset_limit ? sl->offset_limit->val_uint() : ULL(0);
offset_limit_cnt= (ha_rows)val;
#ifndef BIG_TABLES
/* Check for truncation. */
if (val != (ulonglong)offset_limit_cnt)
offset_limit_cnt= HA_POS_ERROR;
#endif
select_limit_cnt= select_limit_val + offset_limit_cnt;
if (select_limit_cnt < select_limit_val)
select_limit_cnt= HA_POS_ERROR; // no limit
}
/**
@brief Set the initial purpose of this TABLE_LIST object in the list of used
tables.
We need to track this information on table-by-table basis, since when this
table becomes an element of the pre-locked list, it's impossible to identify
which SQL sub-statement it has been originally used in.
E.g.:
User request: SELECT * FROM t1 WHERE f1();
FUNCTION f1(): DELETE FROM t2; RETURN 1;
BEFORE DELETE trigger on t2: INSERT INTO t3 VALUES (old.a);
For this user request, the pre-locked list will contain t1, t2, t3
table elements, each needed for different DML.
The trigger event map is updated to reflect INSERT, UPDATE, DELETE,
REPLACE, LOAD DATA, CREATE TABLE .. SELECT, CREATE TABLE ..
REPLACE SELECT statements, and additionally ON DUPLICATE KEY UPDATE
clause.
*/
void LEX::set_trg_event_type_for_tables()
{
uint8 new_trg_event_map= 0;
/*
Some auxiliary operations
(e.g. GRANT processing) create TABLE_LIST instances outside
the parser. Additionally, some commands (e.g. OPTIMIZE) change
the lock type for a table only after parsing is done. Luckily,
these do not fire triggers and do not need to pre-load them.
For these TABLE_LISTs set_trg_event_type is never called, and
trg_event_map is always empty. That means that the pre-locking
algorithm will ignore triggers defined on these tables, if
any, and the execution will either fail with an assert in
sql_trigger.cc or with an error that a used table was not
pre-locked, in case of a production build.
TODO: this usage pattern creates unnecessary module dependencies
and should be rewritten to go through the parser.
Table list instances created outside the parser in most cases
refer to mysql.* system tables. It is not allowed to have
a trigger on a system table, but keeping track of
initialization provides extra safety in case this limitation
is circumvented.
*/
switch (sql_command) {
case SQLCOM_LOCK_TABLES:
/*
On a LOCK TABLE, all triggers must be pre-loaded for this TABLE_LIST
when opening an associated TABLE.
*/
new_trg_event_map= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_INSERT)) |
static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_UPDATE)) |
static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_DELETE));
break;
/*
Basic INSERT. If there is an additional ON DUPLIATE KEY UPDATE
clause, it will be handled later in this method.
*/
case SQLCOM_INSERT: /* fall through */
case SQLCOM_INSERT_SELECT:
/*
LOAD DATA ... INFILE is expected to fire BEFORE/AFTER INSERT
triggers.
If the statement also has REPLACE clause, it will be
handled later in this method.
*/
case SQLCOM_LOAD: /* fall through */
/*
REPLACE is semantically equivalent to INSERT. In case
of a primary or unique key conflict, it deletes the old
record and inserts a new one. So we also may need to
fire ON DELETE triggers. This functionality is handled
later in this method.
*/
case SQLCOM_REPLACE: /* fall through */
case SQLCOM_REPLACE_SELECT:
/*
CREATE TABLE ... SELECT defaults to INSERT if the table or
view already exists. REPLACE option of CREATE TABLE ...
REPLACE SELECT is handled later in this method.
*/
case SQLCOM_CREATE_TABLE:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_INSERT));
break;
/* Basic update and multi-update */
case SQLCOM_UPDATE: /* fall through */
case SQLCOM_UPDATE_MULTI:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_UPDATE));
break;
/* Basic delete and multi-delete */
case SQLCOM_DELETE: /* fall through */
case SQLCOM_DELETE_MULTI:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_DELETE));
break;
default:
break;
}
switch (duplicates) {
case DUP_UPDATE:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_UPDATE));
break;
case DUP_REPLACE:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_DELETE));
break;
case DUP_ERROR:
default:
break;
}
/*
Do not iterate over sub-selects, only the tables in the outermost
SELECT_LEX can be modified, if any.
*/
TABLE_LIST *tables= select_lex.get_table_list();
while (tables)
{
/*
This is a fast check to filter out statements that do
not change data, or tables on the right side, in case of
INSERT .. SELECT, CREATE TABLE .. SELECT and so on.
Here we also filter out OPTIMIZE statement and non-updateable
views, for which lock_type is TL_UNLOCK or TL_READ after
parsing.
*/
if (static_cast<int>(tables->lock_type) >=
static_cast<int>(TL_WRITE_ALLOW_WRITE))
tables->trg_event_map= new_trg_event_map;
tables= tables->next_local;
}
}
/*
Unlink the first table from the global table list and the first table from
outer select (lex->select_lex) local list
SYNOPSIS
unlink_first_table()
link_to_local Set to 1 if caller should link this table to local list
NOTES
We assume that first tables in both lists is the same table or the local
list is empty.
RETURN
0 If 'query_tables' == 0
unlinked table
In this case link_to_local is set.
*/
TABLE_LIST *LEX::unlink_first_table(bool *link_to_local)
{
TABLE_LIST *first;
if ((first= query_tables))
{
/*
Exclude from global table list
*/
if ((query_tables= query_tables->next_global))
query_tables->prev_global= &query_tables;
else
query_tables_last= &query_tables;
first->next_global= 0;
/*
and from local list if it is not empty
*/
if ((*link_to_local= test(select_lex.table_list.first)))
{
select_lex.context.table_list=
select_lex.context.first_name_resolution_table= first->next_local;
select_lex.table_list.first= first->next_local;
select_lex.table_list.elements--; //safety
first->next_local= 0;
/*
Ensure that the global list has the same first table as the local
list.
*/
first_lists_tables_same();
}
}
return first;
}
/*
Bring first local table of first most outer select to first place in global
table list
SYNOPSYS
LEX::first_lists_tables_same()
NOTES
In many cases (for example, usual INSERT/DELETE/...) the first table of
main SELECT_LEX have special meaning => check that it is the first table
in global list and re-link to be first in the global list if it is
necessary. We need such re-linking only for queries with sub-queries in
the select list, as only in this case tables of sub-queries will go to
the global list first.
*/
void LEX::first_lists_tables_same()
{
TABLE_LIST *first_table= select_lex.table_list.first;
if (query_tables != first_table && first_table != 0)
{
TABLE_LIST *next;
if (query_tables_last == &first_table->next_global)
query_tables_last= first_table->prev_global;
if ((next= *first_table->prev_global= first_table->next_global))
next->prev_global= first_table->prev_global;
/* include in new place */
first_table->next_global= query_tables;
/*
We are sure that query_tables is not 0, because first_table was not
first table in the global list => we can use
query_tables->prev_global without check of query_tables
*/
query_tables->prev_global= &first_table->next_global;
first_table->prev_global= &query_tables;
query_tables= first_table;
}
}
/*
Link table back that was unlinked with unlink_first_table()
SYNOPSIS
link_first_table_back()
link_to_local do we need link this table to local
RETURN
global list
*/
void LEX::link_first_table_back(TABLE_LIST *first,
bool link_to_local)
{
if (first)
{
if ((first->next_global= query_tables))
query_tables->prev_global= &first->next_global;
else
query_tables_last= &first->next_global;
query_tables= first;
if (link_to_local)
{
first->next_local= select_lex.table_list.first;
select_lex.context.table_list= first;
select_lex.table_list.first= first;
select_lex.table_list.elements++; //safety
}
}
}
/*
cleanup lex for case when we open table by table for processing
SYNOPSIS
LEX::cleanup_after_one_table_open()
NOTE
This method is mostly responsible for cleaning up of selects lists and
derived tables state. To rollback changes in Query_tables_list one has
to call Query_tables_list::reset_query_tables_list(FALSE).
*/
void LEX::cleanup_after_one_table_open()
{
/*
thd->lex->derived_tables & additional units may be set if we open
a view. It is necessary to clear thd->lex->derived_tables flag
to prevent processing of derived tables during next open_and_lock_tables
if next table is a real table and cleanup & remove underlying units
NOTE: all units will be connected to thd->lex->select_lex, because we
have not UNION on most upper level.
*/
if (all_selects_list != &select_lex)
{
derived_tables= 0;
/* cleunup underlying units (units of VIEW) */
for (SELECT_LEX_UNIT *un= select_lex.first_inner_unit();
un;
un= un->next_unit())
un->cleanup();
/* reduce all selects list to default state */
all_selects_list= &select_lex;
/* remove underlying units (units of VIEW) subtree */
select_lex.cut_subtree();
}
}
/*
Save current state of Query_tables_list for this LEX, and prepare it
for processing of new statemnt.
SYNOPSIS
reset_n_backup_query_tables_list()
backup Pointer to Query_tables_list instance to be used for backup
*/
void LEX::reset_n_backup_query_tables_list(Query_tables_list *backup)
{
backup->set_query_tables_list(this);
/*
We have to perform full initialization here since otherwise we
will damage backed up state.
*/
this->reset_query_tables_list(TRUE);
}
/*
Restore state of Query_tables_list for this LEX from backup.
SYNOPSIS
restore_backup_query_tables_list()
backup Pointer to Query_tables_list instance used for backup
*/
void LEX::restore_backup_query_tables_list(Query_tables_list *backup)
{
this->destroy_query_tables_list();
this->set_query_tables_list(backup);
}
/*
Checks for usage of routines and/or tables in a parsed statement
SYNOPSIS
LEX:table_or_sp_used()
RETURN
FALSE No routines and tables used
TRUE Either or both routines and tables are used.
*/
bool LEX::table_or_sp_used()
{
DBUG_ENTER("table_or_sp_used");
if (sroutines.records || query_tables)
DBUG_RETURN(TRUE);
DBUG_RETURN(FALSE);
}
/*
Do end-of-prepare fixup for list of tables and their merge-VIEWed tables
SYNOPSIS
fix_prepare_info_in_table_list()
thd Thread handle
tbl List of tables to process
DESCRIPTION
Perform end-end-of prepare fixup for list of tables, if any of the tables
is a merge-algorithm VIEW, recursively fix up its underlying tables as
well.
*/
static void fix_prepare_info_in_table_list(THD *thd, TABLE_LIST *tbl)
{
for (; tbl; tbl= tbl->next_local)
{
if (tbl->on_expr)
{
tbl->prep_on_expr= tbl->on_expr;
tbl->on_expr= tbl->on_expr->copy_andor_structure(thd);
}
fix_prepare_info_in_table_list(thd, tbl->merge_underlying_list);
}
}
/*
Save WHERE/HAVING/ON clauses and replace them with disposable copies
SYNOPSIS
st_select_lex::fix_prepare_information
thd thread handler
conds in/out pointer to WHERE condition to be met at execution
having_conds in/out pointer to HAVING condition to be met at execution
DESCRIPTION
The passed WHERE and HAVING are to be saved for the future executions.
This function saves it, and returns a copy which can be thrashed during
this execution of the statement. By saving/thrashing here we mean only
AND/OR trees.
The function also calls fix_prepare_info_in_table_list that saves all
ON expressions.
*/
void st_select_lex::fix_prepare_information(THD *thd, Item **conds,
Item **having_conds)
{
if (!thd->stmt_arena->is_conventional() && first_execution)
{
first_execution= 0;
if (*conds)
{
prep_where= *conds;
*conds= where= prep_where->copy_andor_structure(thd);
}
if (*having_conds)
{
prep_having= *having_conds;
*having_conds= having= prep_having->copy_andor_structure(thd);
}
fix_prepare_info_in_table_list(thd, table_list.first);
}
}
/*
There are st_select_lex::add_table_to_list &
st_select_lex::set_lock_for_tables are in sql_parse.cc
st_select_lex::print is in sql_select.cc
st_select_lex_unit::prepare, st_select_lex_unit::exec,
st_select_lex_unit::cleanup, st_select_lex_unit::reinit_exec_mechanism,
st_select_lex_unit::change_result
are in sql_union.cc
*/
/*
Sets the kind of hints to be added by the calls to add_index_hint().
SYNOPSIS
set_index_hint_type()
type_arg The kind of hints to be added from now on.
clause The clause to use for hints to be added from now on.
DESCRIPTION
Used in filling up the tagged hints list.
This list is filled by first setting the kind of the hint as a
context variable and then adding hints of the current kind.
Then the context variable index_hint_type can be reset to the
next hint type.
*/
void st_select_lex::set_index_hint_type(enum index_hint_type type_arg,
index_clause_map clause)
{
current_index_hint_type= type_arg;
current_index_hint_clause= clause;
}
/*
Makes an array to store index usage hints (ADD/FORCE/IGNORE INDEX).
SYNOPSIS
alloc_index_hints()
thd current thread.
*/
void st_select_lex::alloc_index_hints (THD *thd)
{
index_hints= new (thd->mem_root) List<Index_hint>();
}
/*
adds an element to the array storing index usage hints
(ADD/FORCE/IGNORE INDEX).
SYNOPSIS
add_index_hint()
thd current thread.
str name of the index.
length number of characters in str.
RETURN VALUE
0 on success, non-zero otherwise
*/
bool st_select_lex::add_index_hint (THD *thd, char *str, uint length)
{
return index_hints->push_front (new (thd->mem_root)
Index_hint(current_index_hint_type,
current_index_hint_clause,
str, length));
}
/**
A routine used by the parser to decide whether we are specifying a full
partitioning or if only partitions to add or to split.
@note This needs to be outside of WITH_PARTITION_STORAGE_ENGINE since it
is used from the sql parser that doesn't have any ifdef's
@retval TRUE Yes, it is part of a management partition command
@retval FALSE No, not a management partition command
*/
bool LEX::is_partition_management() const
{
return (sql_command == SQLCOM_ALTER_TABLE &&
(alter_info.flags == ALTER_ADD_PARTITION ||
alter_info.flags == ALTER_REORGANIZE_PARTITION));
}
#ifdef MYSQL_SERVER
uint binlog_unsafe_map[256];
#define UNSAFE(a, b, c) \
{ \
DBUG_PRINT("unsafe_mixed_statement", ("SETTING BASE VALUES: %s, %s, %02X\n", \
LEX::stmt_accessed_table_string(a), \
LEX::stmt_accessed_table_string(b), \
c)); \
unsafe_mixed_statement(a, b, c); \
}
/*
Sets the combination given by "a" and "b" and automatically combinations
given by other types of access, i.e. 2^(8 - 2), as unsafe.
It may happen a colision when automatically defining a combination as unsafe.
For that reason, a combination has its unsafe condition redefined only when
the new_condition is greater then the old. For instance,
. (BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY) is never overwritten by
. (BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF).
*/
void unsafe_mixed_statement(LEX::enum_stmt_accessed_table a,
LEX::enum_stmt_accessed_table b, uint condition)
{
int type= 0;
int index= (1U << a) | (1U << b);
for (type= 0; type < 256; type++)
{
if ((type & index) == index)
{
binlog_unsafe_map[type] |= condition;
}
}
}
/*
The BINLOG_* AND TRX_CACHE_* values can be combined by using '&' or '|',
which means that both conditions need to be satisfied or any of them is
enough. For example,
. BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY means that the statment is
unsafe when the option is on and trx-cache is not empty;
. BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF means the statement is unsafe
in all cases.
. TRX_CACHE_EMPTY | TRX_CACHE_NOT_EMPTY means the statement is unsafe
in all cases. Similar as above.
*/
void binlog_unsafe_map_init()
{
memset((void*) binlog_unsafe_map, 0, sizeof(uint) * 256);
/*
Classify a statement as unsafe when there is a mixed statement and an
on-going transaction at any point of the execution if:
1. The mixed statement is about to update a transactional table and
a non-transactional table.
2. The mixed statement is about to update a transactional table and
read from a non-transactional table.
3. The mixed statement is about to update a non-transactional table
and temporary transactional table.
4. The mixed statement is about to update a temporary transactional
table and read from a non-transactional table.
5. The mixed statement is about to update a transactional table and
a temporary non-transactional table.
6. The mixed statement is about to update a transactional table and
read from a temporary non-transactional table.
7. The mixed statement is about to update a temporary transactional
table and temporary non-transactional table.
8. The mixed statement is about to update a temporary transactional
table and read from a temporary non-transactional table.
After updating a transactional table if:
9. The mixed statement is about to update a non-transactional table
and read from a transactional table.
10. The mixed statement is about to update a non-transactional table
and read from a temporary transactional table.
11. The mixed statement is about to update a temporary non-transactional
table and read from a transactional table.
12. The mixed statement is about to update a temporary non-transactional
table and read from a temporary transactional table.
13. The mixed statement is about to update a temporary non-transactional
table and read from a non-transactional table.
The reason for this is that locks acquired may not protected a concurrent
transaction of interfering in the current execution and by consequence in
the result.
*/
/* Case 1. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_WRITES_NON_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 2. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_READS_NON_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 3. */
UNSAFE(LEX::STMT_WRITES_NON_TRANS_TABLE, LEX::STMT_WRITES_TEMP_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 4. */
UNSAFE(LEX::STMT_WRITES_TEMP_TRANS_TABLE, LEX::STMT_READS_NON_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 5. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 6. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_READS_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 7. */
UNSAFE(LEX::STMT_WRITES_TEMP_TRANS_TABLE, LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 8. */
UNSAFE(LEX::STMT_WRITES_TEMP_TRANS_TABLE, LEX::STMT_READS_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 9. */
UNSAFE(LEX::STMT_WRITES_NON_TRANS_TABLE, LEX::STMT_READS_TRANS_TABLE,
(BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF) & TRX_CACHE_NOT_EMPTY);
/* Case 10 */
UNSAFE(LEX::STMT_WRITES_NON_TRANS_TABLE, LEX::STMT_READS_TEMP_TRANS_TABLE,
(BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF) & TRX_CACHE_NOT_EMPTY);
/* Case 11. */
UNSAFE(LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE, LEX::STMT_READS_TRANS_TABLE,
BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY);
/* Case 12. */
UNSAFE(LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE, LEX::STMT_READS_TEMP_TRANS_TABLE,
BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY);
/* Case 13. */
UNSAFE(LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE, LEX::STMT_READS_NON_TRANS_TABLE,
BINLOG_DIRECT_OFF & TRX_CACHE_NOT_EMPTY);
}
#endif