The root cause of the issue was that the CREATE FUNCTION grammar,
for User Defined Functions, was using the sp_name rule.
The sp_name rule is intended for fully qualified stored procedure names,
like either ident.ident, or just ident but with a default database
implicitly selected.
A UDF does not have a fully qualified name, only a name (ident), and should
not use the sp_name grammar fragment during parsing.
The fix is to re-organize the CREATE FUNCTION grammar, to better separate:
- creating UDF (no definer, can have AGGREGATE, simple ident)
- creating Stored Functions (definer, no AGGREGATE, fully qualified name)
With the test case provided, another issue was exposed which is also fixed:
the DROP FUNCTION statement was using sp_name and also failing when no database
is implicitly selected, when droping UDF functions.
The fix is also to change the grammar so that DROP FUNCTION works with
both the ident.ident syntax (to drop a stored function), or just the ident
syntax (to drop either a UDF or a Stored Function, in the current database)
The problem was that aborted_threads variable was updated
twice when a client connection had been aborted.
The fix is to refactor a code to have aborted_threads updated
only in one place.
When dumping database from a 4.x server, the mysqldump client
inserted a delimiter sign inside special commentaries of the form:
/*!... CREATE DATABASE IF NOT EXISTS ... ;*/
During restoration that dump file was splitten by delimiter signs on
the client side, and the rest of some commentary strings was prepended
to following statements.
The 4x_server_emul test case option has been added for use with the
DBUG_EXECUTE_IF debugging macro. This option affects debug server
builds only to emulate particular behavior of a 4.x server for
the mysqldump client testing. Non-debugging builds are not affected.
The SELECT query with more than 31 nested dependent SELECT queries returned
wrong result.
New error message has been added: ER_TOO_HIGH_LEVEL_OF_NESTING_FOR_SELECT.
It will be reported as: "Too high level of nesting for select".
Problem: thd->thread_specific_used flag is not set executing a statement
containig connection_id() function using PS protocol, that leads to
improper binlog event creation.
Fix: set the flag in the Item_func_connection_id::fix_fields().
Bug #27417 thd->no_trans_update.stmt lost value inside of SF-exec-stack
Once had been set the flag might later got reset inside of a stored routine
execution stack.
The reason was in that there was no check if a new statement started at time
of resetting.
The artifact affects most of binlogable DML queries. Notice, that multi-update
is wrapped up within
bug@27716 fix, multi-delete bug@29136.
Fixed with saving parent's statement flag of whether the statement modified
non-transactional table, and unioning (merging) the value with that was gained
in mysql_execute_command.
Resettling thd->no_trans_update members into thd->transaction.`member`;
Asserting code;
Effectively the following properties are held.
1. At the end of a substatement thd->transaction.stmt.modified_non_trans_table
reflects the fact if such a table got modified by the substatement.
That also respects THD::really_abort_on_warnin() requirements.
2. Eventually thd->transaction.stmt.modified_non_trans_table will be computed as
the union of the values of all invoked sub-statements.
That fixes this bug#27417;
Computing of thd->transaction.all.modified_non_trans_table is refined to base to
the stmt's value for all the case including insert .. select statement which
before the patch had an extra issue bug@28960.
Minor issues are covered with mysql_load, mysql_delete, and binloggin of insert in
to temp_table select.
The supplied test verifies limitely, mostly asserts. The ultimate testing is defered
for bug@13270, bug@23333.
causes full table lock on innodb table.
Also fixes Bug#28502 Triggers that update another innodb table
will block on X lock unnecessarily (duplciate).
Code review fixes.
Both bugs' synopses are misleading: InnoDB table is
not X locked. The statements, however, cannot proceed concurrently,
but this happens due to lock conflicts for tables used in triggers,
not for the InnoDB table.
If a user had an InnoDB table, and two triggers, AFTER UPDATE and
AFTER INSERT, competing for different resources (e.g. two distinct
MyISAM tables), then these two triggers would not be able to execute
concurrently. Moreover, INSERTS/UPDATES of the InnoDB table would
not be able to run concurrently.
The problem had other side-effects (see respective bug reports).
This behavior was a consequence of a shortcoming of the pre-locking
algorithm, which would not distinguish between different DML operations
(e.g. INSERT and DELETE) and pre-lock all the tables
that are used by any trigger defined on the subject table.
The idea of the fix is to extend the pre-locking algorithm to keep track,
for each table, what DML operation it is used for and not
load triggers that are known to never be fired.
Problem: logging queries not using indexes we check a special flag which
is set only at the server startup and is not changing with a corresponding
server variable together.
Fix: check the variable value instead of the flag.
fails if a database is not selected prior.
The problem manifested itself when a user tried to
create a routine that had non-fully-qualified identifiers in its bodies
and there was no current database selected.
This is a regression introduced by the fix for Bug 19022:
The patch for Bug 19022 changes the code to always produce a warning
if we can't resolve the current database in the parser.
In this case this was not necessary, since even though the produced
parsed tree was incorrect, we never re-use sphead
that was obtained at first parsing of CREATE PROCEDURE.
The sphead that is anyhow used is always obtained through db_load_routine,
and there we change the current database to sphead->m_db before
calling yyparse.
The idea of the fix is to resolve the current database directly using
lex->sphead->m_db member when parsing a stored routine body, when
such is present.
This patch removes the need to reset the current database
when loading a trigger or routine definition into SP cache.
The redundant code will be removed in 5.1.
LOCK TABLES takes a list of tables to lock. It may lock several
tables successfully and then encounter a tables that it can't lock,
e.g. because it's locked. In such case it needs to undo the locks on
the already locked tables. And it does that. But it has also notified
the relevant table storage engine handlers that they should lock.
The only reliable way to ensure that the table handlers will give up
their locks is to end the transaction. This is what UNLOCK TABLE
does : it ends the transaction if there were locked tables by LOCK
tables.
It is possible to end the transaction when the lock fails in
LOCK TABLES because LOCK TABLES ends the transaction at its start
already.
Fixed by ending (again) the transaction when LOCK TABLES fails to
lock a table.
ALTER VIEW is currently not supported as a prepared statement
and should be disabled as such as they otherwise could cause server crashes.
ALTER VIEW is currently not supported when called from stored
procedures or functions for related reasons and should also be disabled.
This patch disables these DDL statements and adjusts the appropriate test
cases accordingly.
Additional tests has been added to reflect on the fact that we do support
CREATE/ALTER/DROP TABLE for Prepared Statements (PS), Stored Procedures (SP)
and PS within SP.
protocol
Fixed duplicated code, same as last commit.
One could send a malformed packet that caused the server to SEGV. In
recent versions of the password protocol, the client tells the server
what length the ciphertext is (almost always 20). If that length was
large enough to overflow a signed char, then the number would jump to
very large after being casted to unsigned int.
Instead, cast the *passwd char to uchar.
protocol
One could send a malformed packet that caused the server to SEGV. In
recent versions of the password protocol, the client tells the server
what length the ciphertext is (almost always 20). If that length was
large enough to overflow a signed char, then the number would jump to
very large after being casted to unsigned int.
Instead, cast the *passwd char to uchar.
In case of database level grant the database name may be a pattern,
in case of table|column level grant the database name can not be a pattern.
We use 'dont_check_global_grants' as a flag to determine
if it's database level grant command
(see SQLCOM_GRANT case, mysql_execute_command() function) and
set db_is_pattern according to 'dont_check_global_grants' value.
- The "mysql client in mysqld"(which is used by
replication and federated) should use alarms instead of setting
socket timeout value if the rest of the server uses alarm. By
always calling 'my_net_set_write_timeout'
or 'my_net_set_read_timeout' when changing the timeout value(s), the
selection whether to use alarms or timeouts will be handled by
ifdef's in those two functions.
- Move declaration of 'vio_timeout' into "vio_priv.h"
Bug #23667 "CREATE TABLE LIKE is not isolated from alteration
by other connections"
Bug #18950 "CREATE TABLE LIKE does not obtain LOCK_open"
As well as:
Bug #25578 "CREATE TABLE LIKE does not require any privileges
on source table".
The first and the second bugs resulted in various errors and wrong
binary log order when one tried to execute concurrently CREATE TABLE LIKE
statement and DDL statements on source table or DML/DDL statements on its
target table.
The problem was caused by incomplete protection/table-locking against
concurrent statements implemented in mysql_create_like_table() routine.
We solve it by simply implementing such protection in proper way (see
comment for sql_table.cc for details).
The third bug allowed user who didn't have any privileges on table create
its copy and therefore circumvent privilege check for SHOW CREATE TABLE.
This patch solves this problem by adding privilege check, which was missing.
Finally it also removes some duplicated code from mysql_create_like_table().
Note that, altough tests covering concurrency-related aspects of CREATE TABLE
LIKE behaviour will only be introduced in 5.1, they were run manually for
this patch as well.
Bug #20662 "Infinite loop in CREATE TABLE IF NOT EXISTS ... SELECT
with locked tables"
Bug #20903 "Crash when using CREATE TABLE .. SELECT and triggers"
Bug #24738 "CREATE TABLE ... SELECT is not isolated properly"
Bug #24508 "Inconsistent results of CREATE TABLE ... SELECT when
temporary table exists"
Deadlock occured when one tried to execute CREATE TABLE IF NOT
EXISTS ... SELECT statement under LOCK TABLES which held
read lock on target table.
Attempt to execute the same statement for already existing
target table with triggers caused server crashes.
Also concurrent execution of CREATE TABLE ... SELECT statement
and other statements involving target table suffered from
various races (some of which might've led to deadlocks).
Finally, attempt to execute CREATE TABLE ... SELECT in case
when a temporary table with same name was already present
led to the insertion of data into this temporary table and
creation of empty non-temporary table.
All above problems stemmed from the old implementation of CREATE
TABLE ... SELECT in which we created, opened and locked target
table without any special protection in a separate step and not
with the rest of tables used by this statement.
This underminded deadlock-avoidance approach used in server
and created window for races. It also excluded target table
from prelocking causing problems with trigger execution.
The patch solves these problems by implementing new approach to
handling of CREATE TABLE ... SELECT for base tables.
We try to open and lock table to be created at the same time as
the rest of tables used by this statement. If such table does not
exist at this moment we create and place in the table cache special
placeholder for it which prevents its creation or any other usage
by other threads.
We still use old approach for creation of temporary tables.
Also note that we decided to postpone introduction of some tests
for concurrent behaviour of CREATE TABLE ... SELECT till 5.1.
The main reason for this is absence in 5.0 ability to set @@debug
variable at runtime, which can be circumvented only by using several
test files with individual .opt files. Since the latter is likely
to slowdown test-suite unnecessary we chose not to push this tests
into 5.0, but run them manually for this version and later push
their optimized version into 5.1
The issue found with bug 25411 is due to the function skip_rear_comments()
which damages the source code while implementing a work around.
The root cause of the problem is in the lexical analyser, which does not
process special comments properly.
For special comments like :
[1] aaa /*!50000 bbb */ ccc
since 5.0 is a version older that the current code, the parser is in lining
the content of the special comment, so that the query to process is
[2] aaa bbb ccc
However, the text of the query captured when processing a stored procedure,
stored function or trigger (or event in 5.1), can be after rebuilding it:
[3] aaa bbb */ ccc
which is wrong.
To fix bug 25411 properly, the lexical analyser needs to return [2] when
in lining special comments.
In order to implement this, some preliminary cleanup is required in the code,
which is implemented by this patch.
Before this change, the structure named LEX (or st_lex) contains attributes
that belong to lexical analysis, as well as attributes that represents the
abstract syntax tree (AST) of a statement.
Creating a new LEX structure for each statements (which makes sense for the
AST part) also re-initialized the lexical analysis phase each time, which
is conceptually wrong.
With this patch, the previous st_lex structure has been split in two:
- st_lex represents the Abstract Syntax Tree for a statement. The name "lex"
has not been changed to avoid a bigger impact in the code base.
- class lex_input_stream represents the internal state of the lexical
analyser, which by definition should *not* be reinitialized when parsing
multiple statements from the same input stream.
This change is a pre-requisite for bug 25411, since the implementation of
lex_input_stream will later improve to deal properly with special comments,
and this processing can not be done with the current implementation of
sp_head::reset_lex and sp_head::restore_lex, which interfere with the lexer.
This change set alone does not fix bug 25411.
The problem was that THD::db_access variable was not restored after
database switch in stored-routine-execution code.
The fix is to restore THD::db_access in this case.
Unfortunately, this fix requires additional changes,
because in prepare_schema_table(), called on the parsing stage, we checked
privileges. That was wrong according to our design, but this flaw haven't
struck so far, because it was masked. All privilege checkings must be
done on the execution stage in order to be compatible with prepared statements
and stored routines. So, this patch also contains patch for
prepare_schema_table(), which moves the checkings to the execution phase.
execution breaks replication.
When a stored routine is executed, we switch current
database to the database, in which the routine
has been created. When the stored routine finishes,
we switch back to the original database.
The problem was that if the original database does not
exist (anymore) after routine execution, we raised an error.
The fix is to report a warning, and switch to the NULL database.
thd->options' OPTION_STATUS_NO_TRANS_UPDATE bit was not restored at the end of SF() invocation, where
SF() modified non-ta table.
As the result of this artifact it was not possible to detect whether there were any side-effects when
top-level query ends.
If the top level query table was not modified and the bit is lost there would be no binlogging.
Fixed with preserving the bit inside of thd->no_trans_update struct. The struct agregates two bool flags
telling whether the current query and the current transaction modified any non-ta table.
The flags stmt, all are dropped at the end of the query and the transaction.
