Added re-parsing of failed statements inside a stored routine.
General idea of the patch is to install an instance of the class
Reprepare_observer before executing a next SP instruction and
re-parse a statement of this SP instruction in case of
its execution failure.
To implement the described approach the class sp_lex_keeper
has been extended with the method validate_lex_and_exec_core()
that is just a wrapper around the method reset_lex_and_exec_core()
with additional setting/resetting an instance of the class
Reprepare_observer on each iteration of SP instruction
execution.
If reset_lex_and_exec_core() returns error and an instance
of the class Reprepare_observer is installed before running
a SP instruction then a number of attempts to re-run the SP
instruction is checked against a max. limit and in case it doesn't
reach the limit a statement for the failed SP instruction is re-parsed.
Re-parsing of a statement for the failed SP instruction is implemented
by the new method sp_le_inst::parse_expr() that prepends
a SP instruction's statement with the clause 'SELECT' and parse it.
Own SP instruction MEM_ROOT and a separate free_list is used for
parsing of a SP statement. On successful re-parsing of SP instruction's
statement the virtual methods adjust_sql_command() and
on_after_expr_parsing() of the class sp_lex_instr is called
to update the SP instruction state with a new data created
on parsing the statement.
Few words about reason for prepending a SP instruction's statement
with the clause 'SELECT' - this is required step to produce a valid
SQL statement, since for some SP instructions the instructions statement
is not a valid SQL statement. Wrapping such text into 'SELECT ( )'
produces a correct operator from SQL syntax point of view.
For those SP instructions that need to get access to ia LEX object
on execution, added storing of their original sql expressions inside
classes derived from the class sp_lex_instr.
A stored sql expression is returned by the abstract method
sp_lex_instr::get_expr_query
redefined in derived classes.
Since an expression constituting a SP instruction can be invalid
SQL statement in general case (not parseable statement), the virtual
method sp_lex_instr::get_query() is introduced to return a valid string
for a statement that corresponds to the given instruction.
Additionally, introduced the rule remember_start_opt in the grammar.
The new rule intended to get correct position of a current
token taking into attention the fact whether lookahead was done or not.
This is the prerequisite patch to move the data member
LEX::trg_table_fields to the class sp_head and rename it as
m_trg_table_fields.
This data member is used for handling OLD/NEW pseudo-rows inside
a trigger body and in order to be able to re-parse a trigger body
the data member must be moved from the struct LEX to the class sp_head.
This is the prerequisite patch to remove the data member
sp_head::m_trg_table_fields and the method is_fields_updated_in_trigger
that used it but is not called anywhere in the source code.
The commit 5f1f2fc0e4 introduced the
data member sp_head::m_trg_table_fields and the method
Table_triggers_list::is_fields_updated_in_trigger() that used this data member.
The method Table_triggers_list::is_fields_updated_in_trigger() was invoked
by the method partition_info::can_prune_insert() also introduced by
the same commit 5f1f2fc0e4
The method partition_info::can_prune_insert() is not called anywhere
in the code and later these methods were removed from the source code
but the data member sp_head::m_trg_table_fields wasn't.
So, remove the data member sp_head::m_trg_table_fields and declaration of
the method is_fields_updated_in_trigger() for purpose of code cleaning up.
This is the prerequisite patch to move the sp_instr class and classes derived
from it into the files sp_instr.cc/sp_instr.h. The classes sp_lex_cursor and
sp_lex_keeper are also moved to the files files sp_instr.cc/sp_instr.h.
Additionally,
* all occurrences of macroses NULL, FALSE, TRUE are replaced
with the corresponding C++ keywords nullptr, false, true.
* the keyword 'override' is added in and the keyword 'virtual' is removed
from signatures of every virtual method implemented in classes derived
from the base class sp_instr.
* the keyword 'final' is added into declaration of the class sp_lex_keeper
since this class shouldn't have a derived class by design.
* the function cmp_rqp_locations is made static since it is not called
outside the file sp_instr.cc.
* the function subst_spvars() is moved into the file sp_instr.cc since this
function used only by the method sp_instr_stmt::execute
This patch is the result of running
run-clang-tidy -fix -header-filter=.* -checks='-*,modernize-use-equals-default' .
Code style changes have been done on top. The result of this change
leads to the following improvements:
1. Binary size reduction.
* For a -DBUILD_CONFIG=mysql_release build, the binary size is reduced by
~400kb.
* A raw -DCMAKE_BUILD_TYPE=Release reduces the binary size by ~1.4kb.
2. Compiler can better understand the intent of the code, thus it leads
to more optimization possibilities. Additionally it enabled detecting
unused variables that had an empty default constructor but not marked
so explicitly.
Particular change required following this patch in sql/opt_range.cc
result_keys, an unused template class Bitmap now correctly issues
unused variable warnings.
Setting Bitmap template class constructor to default allows the compiler
to identify that there are no side-effects when instantiating the class.
Previously the compiler could not issue the warning as it assumed Bitmap
class (being a template) would not be performing a NO-OP for its default
constructor. This prevented the "unused variable warning".
Problem: Currently stored function does not support IN/OUT/INOUT parameter qualifiers.
This is needed for Oracle compatibility (sql_mode = ORACLE).
Solution: Implemented parameter qualifier support to CREATE FUNCTION (reference: CREATE PROCEDURE)
Implemented return by reference for OUT/INOUT parameters in execute_function() (reference: execute_procedure())
Files changed:
sql/sql_yacc.yy: Added IN, OUT, INOUT parameter qualifiers for CREATE FUNCTION.
sql/sp_head.cc: Added input and output parameter binding for IN/OUT/INOUT parameters in execute_function() so that OUT/INOUT can return by reference.
sql/share/errmsg-utf8.txt: Added error message to restrict OUT/INOUT parameters while function being called from SQL query.
mysql-test/suite/compat/oracle/t/sp-inout.test: Added test cases
mysql-test/suite/compat/oracle/r/sp-inout.result: Added test results
Reviewed-by: iqbal@hasprime.com
Problem:
At some point, we made stored rountines fail at CREATE time
instead of execution time in case of this syntax:
IF unknown_variable
...
END IF
As a result, a trigger created before this change and contained an unknown
variable worked in a bad way after upgrade:
- It was displayed with an empty trigger name by SHOW CREATE TRIGGER
- It was displayed with an empty trigger name by INFORMATION_SCHEMA.TRIGGERS
- An attempt to DROP this trigger returned errors - nothing happened.
- DROP TABLE did not remove the .TRN file corresponding to this broken trigger.
Underlying code observations:
The old code assumed that the trigger name resides in the current lex:
if(thd->lex->spname)
m_trigger_name= &thd->lex->spname->m_name;
This is not always the case. Some SP statements (e.g. IF)
do the following in their beginning:
- create a separate local LEX
- set thd->lex to this new local LEX
- push the new local LEX to the stack in sp_head::m_lex
and the following at the end of the statement:
- pop the previous LEX from the stack sp_head::m_lex
- set thd->lex back to the popped value
So when the parse error happens inside e.g. IF statement, thd->lex->spname
is a NULL pointer, because thd->lex points to the local LEX (without SP name)
rather than the top level LEX (with SP name).
Fix:
- Adding a new method sp_head::find_spname_recursive()
which walks inside the LEX stack sp_head::m_lex from
the top (the newest, most local) to the bottom (the oldest),
and finds the one which contains a non-zero spname pointer.
- Using the new method inside
Deprecated_trigger_syntax_handler::handle_condition():
First it still tests thd->lex->spname (like before this change),
and uses it in case it is not empty.
Otherwise (if thd->lex->spname is empty), it calls
sp_head::find_spname_recursive() to find the LEX with a
non-empty spname inside the LEX stack of the current sphead.
https://jira.mariadb.org/browse/MDEV-26221
my_sys DYNAMIC_ARRAY and DYNAMIC_STRING inconsistancy
The DYNAMIC_STRING uses size_t for sizes, but DYNAMIC_ARRAY used uint.
This patch adjusts DYNAMIC_ARRAY to use size_t like DYNAMIC_STRING.
As the MY_DIR member number_of_files is copied from a DYNAMIC_ARRAY,
this is changed to be size_t.
As MY_TMPDIR members 'cur' and 'max' are copied from a DYNAMIC_ARRAY,
these are also changed to be size_t.
The lists of plugins and stored procedures use DYNAMIC_ARRAY,
but their APIs assume a size of 'uint'; these are unchanged.
(Variant #2 of the patch, which keeps the sp_head object inside the
MEM_ROOT that sp_head object owns)
(10.3 requires extra work due to sp_package, will commit a separate
patch for it)
sp_head::operator new() and operator delete() were dereferencing sp_head*
pointers to memory that didn't hold a valid sp_head object (it was
not created/already destroyed).
This caused UBSan to crash when looking up type information.
Fixed by providing static sp_head::create() and sp_head::destroy() methods.
(Variant #2 of the patch, which keeps the sp_head object inside the
MEM_ROOT that sp_head object owns)
(10.3 version of the fix, with handling for class sp_package)
sp_head::operator new() and operator delete() were dereferencing sp_head*
pointers to memory that didn't hold a valid sp_head object (it was
not created/already destroyed).
This caused UBSan to crash when looking up type information.
Fixed by providing static sp_head::create() and sp_head::destroy() methods.
Part#2 (final): rewritting the code to pass the correct enum_sp_aggregate_type
to the sp_head constructor, so sp_head never changes its aggregation type
later on. The grammar has been simplified and defragmented.
This allowed to check aggregate specific instructions right after
a routine body has been scanned, by calling new LEX methods:
sp_body_finalize_{procedure|function|trigger|event}()
Moving some C++ code from *.yy to a few new helper methods in LEX.
This task involves the implementation for the optimizer trace.
This feature produces a trace for any SELECT/UPDATE/DELETE/,
which contains information about decisions taken by the optimizer during
the optimization phase (choice of table access method, various costs,
transformations, etc). This feature would help to tell why some decisions were
taken by the optimizer and why some were rejected.
Trace is session-local, controlled by the @@optimizer_trace variable.
To enable optimizer trace we need to write:
set @@optimizer_trace variable= 'enabled=on';
To display the trace one can run:
SELECT trace FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
This task also involves:
MDEV-18489: Limit the memory used by the optimizer trace
introduces a switch optimizer_trace_max_mem_size which limits
the memory used by the optimizer trace. This was implemented by
Sergei Petrunia.
Problem:
push_handler() created sp_handler_entry instances on THD::main_mem_root,
which is freed only after the SP instructions execution.
So in case of a CONTINUE HANDLER inside a loop (e.g. WHILE) this approach
leaked thread memory on every loop iteration.
Changes:
- Removing sp_handler_entry declaration, it's not really needed.
- Fixing the data type of sp_rcontext::m_handlers from
Dynamic_array<sp_handler_entry*> to Dynamic_array<sp_instr_hpush_jump*>
- Fixing sp_rcontext::push_handler() to push the pointer to
an sp_instr_hpush_jump instance to the handler stack.
This instance contains everything we need.
There is no a need to allocate anything else.
Problem:
push_cursor() created sp_cursor instances on THD::main_mem_root,
which is freed only after the SP instructions loop.
Changes:
- Moving sp_cursor declaration from sp_rcontext.h to sql_class.h
- Deriving sp_instr_cpush from sp_cursor. So now sp_cursor is created
only once (at the SP parse time) and then reused on all loop iterations
- Adding a new method reset() into sp_cursor (and its parent classes)
to reset an sp_cursor instance before reuse.
- Moving former sp_cursor members m_fetch_count, m_row_count, m_found
into a separate class sp_cursor_statistics. This helps to reuse
the code in sp_cursor constructors, and in sp_cursor::reset()
- Adding a helper method sp_rcontext::pop_cursor().
- Adding "THD*" parameter to so_rcontext::pop_cursors() and pop_all_cursors()
- Removing "new" and "delete" from sp_rcontext::push_cursor() and
sp_rconext::pop_cursor().
- Fixing sp_cursor not to derive from Sql_alloc, as it's now allocated
only as a part of sp_instr_cpush (and not allocated separately).
- Moving lex_keeper->disable_query_cache() from sp_cursor::sp_cursor()
to sp_instr_cpush::execute().
- Adding tests
MDEV-10581 sql_mode=ORACLE: Explicit cursor FOR LOOP
MDEV-12098 sql_mode=ORACLE: Implicit cursor FOR loop
Cleanup changes:
- Removing sp_lex_cursor::m_cursor_name
- Adding sp_instr_cursor_copy_struct::m_cursor (the cursor global index)
- Fixing sp_instr_cursor_copy_struct::print() to access to the cursor
name using m_ctx and m_cursor (like other cursor related instructions do)
instead of m_cursor_name.
This change is needed to unify sp_assignment_lex and sp_cursor_lex later,
to fix this problem easier:
MDEV-16558 Parenthesized expression does not work as a lower FOR loop bound
The print() function was missing from the FETCH GROUP NEXT ROW instrunction class, so there was no
output for this particular instruction when we use the query SHOW FUNCTION CODE function_name
- CREATE PACKAGE [BODY] statements are now
entirely written to mysql.proc with type='PACKAGE' and type='PACKAGE BODY'.
- CREATE PACKAGE BODY now supports IF NOT EXISTS
- DROP PACKAGE BODY now supports IF EXISTS
- CREATE OR REPLACE PACKAGE [BODY] is now supported
- CREATE PACKAGE [BODY] now support the DEFINER clause:
CREATE DEFINER user@host PACKAGE pkg ... END;
CREATE DEFINER user@host PACKAGE BODY pkg ... END;
- CREATE PACKAGE [BODY] now supports SQL SECURITY and COMMENT clauses, e.g.:
CREATE PACKAGE p1 SQL SECURITY INVOKER COMMENT "comment" AS ... END;
- Package routines are now created from the package CREATE PACKAGE BODY
statement and don't produce individual records in mysql.proc.
- CREATE PACKAGE BODY now supports package-wide variables.
Package variables can be read and set inside package routines.
Package variables are stored in a separate sp_rcontext,
which is cached in THD on the first packate routine call.
- CREATE PACKAGE BODY now supports the initialization section.
- All public routines (i.e. declared in CREATE PACKAGE)
must have implementations in CREATE PACKAGE BODY
- Only public package routines are available outside of the package
- {CREATE|DROP} PACKAGE [BODY] now respects CREATE ROUTINE and ALTER ROUTINE
privileges
- "GRANT EXECUTE ON PACKAGE BODY pkg" is now supported
- SHOW CREATE PACKAGE [BODY] is now supported
- SHOW PACKAGE [BODY] STATUS is now supported
- CREATE and DROP for PACKAGE [BODY] now works for non-current databases
- mysqldump now supports packages
- "SHOW {PROCEDURE|FUNCTION) CODE pkg.routine" now works for package routines
- "SHOW PACKAGE BODY CODE pkg" now works (the package initialization section)
- A new package body level MDL was added
- Recursive calls for package procedures are now possible
- Routine forward declarations in CREATE PACKATE BODY are now supported.
- Package body variables now work as SP OUT parameters
- Package body variables now work as SELECT INTO targets
- Package body variables now support ROW, %ROWTYPE, %TYPE
Handle string length as size_t, consistently (almost always:))
Change function prototypes to accept size_t, where in the past
ulong or uint were used. change local/member variables to size_t
when appropriate.
This fix excludes rocksdb, spider,spider, sphinx and connect for now.
Counter for select numbering made stored with the statement (before was global)
So now it does have always accurate value which does not depend on
interruption of statement prepare by errors like lack of table in
a view definition.
