Problem: Statements that write to tables with auto_increment columns
based on the selection from another table, may lead to master
and slave going out of sync, as the order in which the rows
are retrived from the table may differ on master and slave.
Solution: We mark writing to a table with auto_increment table
as unsafe. This will cause the execution of such statements to
throw a warning and forces the statement to be logged in ROW if
the logging format is mixed.
Changes:
1. All the statements that writes to a table with auto_increment
column(s) based on the rows fetched from another table, will now
be unsafe.
2. CREATE TABLE with SELECT will now be unsafe.
sql/share/errmsg-utf8.txt:
Added new Warning messages
sql/sql_base.cc:
created a new function that checks for select + write on a autoinc table
made all such statements to be unsafe.
sql/sql_parse.cc:
made create autoincremnet tabble + select unsafe
Problem: Statements that write to tables with auto_increment columns
based on the selection from another table, may lead to master
and slave going out of sync, as the order in which the rows
are retrived from the table may differ on master and slave.
Solution: We mark writing to a table with auto_increment table
as unsafe. This will cause the execution of such statements to
throw a warning and forces the statement to be logged in ROW if
the logging format is mixed.
Changes:
1. All the statements that writes to a table with auto_increment
column(s) based on the rows fetched from another table, will now
be unsafe.
2. CREATE TABLE with SELECT will now be unsafe.
MEMORY LEAK.
Background:
- There are caches for stored functions and stored procedures (SP-cache);
- There is no similar cache for events;
- Triggers are cached together with TABLE objects;
- Those SP-caches are per-session (i.e. specific to each session);
- A stored routine is represented by a sp_head-instance internally;
- SP-cache basically contains sp_head-objects of stored routines, which
have been executed in a session;
- sp_head-object is added into the SP-cache before the corresponding
stored routine is executed;
- SP-cache is flushed in the end of the session.
The problem was that SP-cache might grow without any limit. Although this
was not a pure memory leak (the SP-cache is flushed when session is closed),
this is still a problem, because the user might take much memory by
executing many stored routines.
The patch fixes this problem in the least-intrusive way. A soft limit
(similar to the size of table definition cache) is introduced. To represent
such limit the new runtime configuration parameter 'stored_program_cache'
is introduced. The value of this parameter is stored in the new global
variable stored_program_cache_size that used to control the size of SP-cache
to overflow.
The parameter 'stored_program_cache' limits number of cached routines for
each thread. It has the following min/default/max values given from support:
min = 256, default = 256, max = 512 * 1024.
Also it should be noted that this parameter limits the size of
each cache (for stored procedures and for stored functions) separately.
The SP-cache size is checked after top-level statement is parsed.
If SP-cache size exceeds the limit specified by parameter
'stored_program_cache' then SP-cache is flushed and memory allocated for
cache objects is freed. Such approach allows to flush cache safely
when there are dependencies among stored routines.
sql/mysqld.cc:
Added global variable stored_program_cache_size to store value of
configuration parameter 'stored-program-cache'.
sql/mysqld.h:
Added declaration of global variable stored_program_cache_size.
sql/sp_cache.cc:
Extended interface for sp_cache by adding helper routine
sp_cache_enforce_limit to control size of stored routines cache for
overflow. Also added method enforce_limit into class sp_cache that
implements control of cache size for overflow.
sql/sp_cache.h:
Extended interface for sp_cache by adding standalone routine
sp_cache_enforce_limit to control size of stored routines cache
for overflow.
sql/sql_parse.cc:
Added flush of sp_cache after processing of next sql-statement
received from a client.
sql/sql_prepare.cc:
Added flush of sp_cache after preparation/execution of next prepared
sql-statement received from a client.
sql/sys_vars.cc:
Added support for configuration parameter stored-program-cache.
MEMORY LEAK.
Background:
- There are caches for stored functions and stored procedures (SP-cache);
- There is no similar cache for events;
- Triggers are cached together with TABLE objects;
- Those SP-caches are per-session (i.e. specific to each session);
- A stored routine is represented by a sp_head-instance internally;
- SP-cache basically contains sp_head-objects of stored routines, which
have been executed in a session;
- sp_head-object is added into the SP-cache before the corresponding
stored routine is executed;
- SP-cache is flushed in the end of the session.
The problem was that SP-cache might grow without any limit. Although this
was not a pure memory leak (the SP-cache is flushed when session is closed),
this is still a problem, because the user might take much memory by
executing many stored routines.
The patch fixes this problem in the least-intrusive way. A soft limit
(similar to the size of table definition cache) is introduced. To represent
such limit the new runtime configuration parameter 'stored_program_cache'
is introduced. The value of this parameter is stored in the new global
variable stored_program_cache_size that used to control the size of SP-cache
to overflow.
The parameter 'stored_program_cache' limits number of cached routines for
each thread. It has the following min/default/max values given from support:
min = 256, default = 256, max = 512 * 1024.
Also it should be noted that this parameter limits the size of
each cache (for stored procedures and for stored functions) separately.
The SP-cache size is checked after top-level statement is parsed.
If SP-cache size exceeds the limit specified by parameter
'stored_program_cache' then SP-cache is flushed and memory allocated for
cache objects is freed. Such approach allows to flush cache safely
when there are dependencies among stored routines.
- Changed storage to be 2 bytes instead of sizeof(size_t) (simple optimization)
- Fixed bug when using query_cache_strip_comments and query that started with '('
- Fixed DBUG_PRINT() that used wrong (not initialized) variables.
mysql-test/mysql-test-run.pl:
Added some space to make output more readable.
mysql-test/r/query_cache.result:
Updated test results
mysql-test/t/query_cache.test:
Added test with query_cache_strip_comments
sql/mysql_priv.h:
Added QUERY_CACHE_DB_LENGTH_SIZE
sql/sql_cache.cc:
Fixed bug when using query_cache_strip_comments and query that started with '('
Store db length in 2 characters instead of size_t.
Get db length from correct position (earlier we had an error when query started with ' ')
Fixed DBUG_PRINT() that used wrong (not initialized) variables.
The problem was that merged views has its own nest_level numbering =>
when we compare nest levels we should take into considiration basis (i.e. 0 level),
if it is different then nest levels are not comparable.
The bug case is similar to one fixed earlier bug_49536.
Deadlock involving LOCK_log appears to be possible because the purge running thread
is holding LOCK_log whereas there is no sense of doing that and which fact was
exploited by the earlier bug fixes.
Fixed with small reengineering of rotate_and_purge(), adding two new methods and
setting up a policy to execute those instead of the former
rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED).
The policy for using rotate(), purge() is that if the caller acquires LOCK_log itself,
it should call rotate(), release the mutex and run purge().
Side effect of this patch is refining error message of bug@11747416 to print
the whole path.
mysql-test/suite/rpl/r/rpl_cant_read_event_incident.result:
the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_log_pos.result:
the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_manual_change_index_file.result:
the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_packet.result:
the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_rotate_purge_deadlock.result:
new result file is added.
mysql-test/suite/rpl/t/rpl_cant_read_event_incident.test:
The test of that bug can't satisfy windows and unix backslash interpretation so windows
execution is chosen to bypass.
mysql-test/suite/rpl/t/rpl_rotate_purge_deadlock-master.opt:
new opt file is added.
mysql-test/suite/rpl/t/rpl_rotate_purge_deadlock.test:
regression test is added as well as verification of a
possible side effect of the fixes is tried.
sql/log.cc:
LOCK_log is never taken during execution of log purging routine.
The former MYSQL_BIN_LOG::rotate_and_purge is made to necessarily
acquiring and releasing LOCK_log.
If caller takes the mutex itself it has to use a new rotate(), purge()
methods combination and to never let purge() be run with LOCK_log grabbed.
split apart to allow
the caller to chose either it
Simulation of concurrently rotating/purging threads is added.
sql/log.h:
new rotate(), purge() methods are added to be used instead of
the former rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED).
rotate_and_purge() signature is changed. Caller should not call rotate_and_purge()
but rather {rotate(), purge()} if LOCK_log is acquired by it.
sql/rpl_injector.cc:
changes to reflect the new rotate_and_purge() signature.
sql/sql_class.h:
unnecessary constants are removed.
sql/sql_parse.cc:
changes to reflect the new rotate_and_purge() signature.
sql/sql_reload.cc:
changes to reflect the new rotate_and_purge() signature.
sql/sql_repl.cc:
followup for bug@11747416: the file name printing is changed to a relative
path instead of just the file name.
The bug case is similar to one fixed earlier bug_49536.
Deadlock involving LOCK_log appears to be possible because the purge running thread
is holding LOCK_log whereas there is no sense of doing that and which fact was
exploited by the earlier bug fixes.
Fixed with small reengineering of rotate_and_purge(), adding two new methods and
setting up a policy to execute those instead of the former
rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED).
The policy for using rotate(), purge() is that if the caller acquires LOCK_log itself,
it should call rotate(), release the mutex and run purge().
Side effect of this patch is refining error message of bug@11747416 to print
the whole path.
sql/sql_insert.cc:
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
******
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
sql/sql_table.cc:
small cleanup
******
small cleanup
A buffer large enough to hold the query _plus_ some additional
data is allocated before parsing is started. The additional data
is used by the query cache, and consists of the name of the current
database and a set of flags.
When a packet containing multiple SQL statements is sent to the
server and one of the statements changes the current database
(a "USE <db>" statement), and the name of the new current database
is longer than of the previous, there is not enough space in the
buffer for the new name, and we write out over the buffer boundary.
The fix adds an extra field to store the number of bytes
allocated to the database name in the buffer. If the current
database name changes, and the new name is longer than the
previous one, we refuse to cache the query.
A buffer large enough to hold the query _plus_ some additional
data is allocated before parsing is started. The additional data
is used by the query cache, and consists of the name of the current
database and a set of flags.
When a packet containing multiple SQL statements is sent to the
server and one of the statements changes the current database
(a "USE <db>" statement), and the name of the new current database
is longer than of the previous, there is not enough space in the
buffer for the new name, and we write out over the buffer boundary.
The fix adds an extra field to store the number of bytes
allocated to the database name in the buffer. If the current
database name changes, and the new name is longer than the
previous one, we refuse to cache the query.
