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.
NEW_FRM_MEM WITHOUT NEEDING TO".
During the process of opening tables for a statement, we allocated
memory which was used only during view loading even in cases when the
statement didn't use any views. Such an unnecessary allocation (and
corresponding freeing) might have caused significant performance
overhead in some workloads. For example, it caused up to 15% slowdown
in a simple stored routine calculating Fibonacci's numbers.
This memory was pre-allocated as part of "new_frm_mem" MEM_ROOT
initialization at the beginning of open_tables().
This patch addresses this issue by turning off memory pre-allocation
during initialization for this MEM_ROOT. Now, memory on this root
will be allocated only at the point when the first .FRM for a view is
opened.
The patch doesn't contain a test case since it is hard to test the
performance improvements or the absence of memory allocation in our
test framework.
warnings are converted to errors, the compiler complains about
the fact that binlog_can_be_corrupted is defined but never used.
We need to check if this is a dead code or if someone removed any
code by mistake.
When temporary tables is used for result sorting
result field for gconcat function is created using
group_concat_max_len size. It leads to result truncation
when character_set_results is multi-byte character set due
to insufficient tmp table field size.
The fix is to increase temporary table field size for
gconcat. Method make_string_field() is overloaded
for Item_func_group_concat class and uses
max_characters * collation.collation->mbmaxlen size for
result field. max_characters is maximum number of characters
what can fit into max_length size.
Problematic query:
insert ignore into `t1_federated` (`c1`) select `c1` from `t1_local` a
where not exists (select 1 from `t1_federated` b where a.c1 = b.c1);
When this query is killed in another connection it could lead to crash.
The problem is follwing:
An attempt to obtain table statistics for subselect table in killed query
fails with an error. So JOIN::optimize() for subquery is failed but
it does not prevent further subquery evaluation.
At the first subquery execution JOIN::optimize() is called
(see subselect_single_select_engine::exec()) and fails with
an error. 'executed' flag is set to TRUE and it prevents
further subquery evaluation. At the second call
JOIN::optimize() does not happen as 'JOIN::optimized' is TRUE
and in case of uncacheable subquery the 'executed' flag is set
to FALSE before subquery evaluation. So we loose 'optimize stage'
error indication (see subselect_single_select_engine::exec()).
In other words 'executed' flag is used for two purposes, for
error indication at JOIN::optimize() stage and for an
indication of subquery execution. And it seems it's wrong
as the flag could be reset.
Binary log of master can get a partially logged event if the server
runs out of disk space and, while waiting for some space to be freed,
is shut down (or crashes). If the server is not stopped, it will just
wait endlessly for space to be freed, thus no partial event anomaly
occurs. The restarted master server has had a dubious policy to send
the incomplete event to slave which it apparently can't handle.
Although an error was printed out the fact of sending with unclear
error message is a source of confusion.
Actually the problem of presence an incomplete event in the binary log
was already fixed by WL 5493 (which was merged to our current trunk
branch, major version 5.6). The fix makes the server truncate the
binary log on server restart and recovery.
However 5.5 master can't do that. So the current issue is a problem of
sending incomplete events to the slave by 5.5 master.
It is fixed in this patch by changing the policy so that only complete
events are pushed by the dump thread to the IO thread. In addition,
the error text that master sends to the slave when an incomplete event
is found, now states that incomplete event may have been caused by an
out-of-disk space situation and provides coordinates of
the first and the last event bytes read.
Problem: The following statements can cause the slave to go out of sync
if logged in statement format:
INSERT IGNORE...SELECT
INSERT ... SELECT ... ON DUPLICATE KEY UPDATE
REPLACE ... SELECT
UPDATE IGNORE :
CREATE ... IGNORE SELECT
CREATE ... REPLACE SELECT
Background: Since the order of the rows returned by the SELECT
statement or otherwise may differ on master and slave, therefore
the above statements may cuase the salve to go out of sync with
the master.
Fix:
Issue a warning when statements like the above are exectued and
the bin-logging format is statement. If the logging format is mixed,
use row based logging. Marking a statement as unsafe has been
done in the sql/sql_parse.cc instead of sql/sql_yacc.cc, because while
parsing for a token has been done we cannot be sure if the parsing
of the other tokens has been done as well.
Six new warning messages has been added for each unsafe statement.
binlog.binlog_unsafe.test has been updated to incoporate these additional unsafe statments.
******
BUG#11758262 - 50439: MARK INSERT...SEL...ON DUP KEY UPD,REPLACE...SEL,CREATE...[IGN|REPL] SEL
Problem: The following statements can cause the slave to go out of sync
if logged in statement format:
INSERT IGNORE...SELECT
INSERT ... SELECT ... ON DUPLICATE KEY UPDATE
REPLACE ... SELECT
UPDATE IGNORE :
CREATE ... IGNORE SELECT
CREATE ... REPLACE SELECT
Background: Since the order of the rows returned by the SELECT
statement or otherwise may differ on master and slave, therefore
the above statements may cuase the salve to go out of sync with
the master.
Fix:
Issue a warning when statements like the above are exectued and
the bin-logging format is statement. If the logging format is mixed,
use row based logging. Marking a statement as unsafe has been
done in the sql/sql_parse.cc instead of sql/sql_yacc.cc, because while
parsing for a token has been done we cannot be sure if the parsing
of the other tokens has been done as well.
Six new warning messages has been added for each unsafe statement.
binlog.binlog_unsafe.test has been updated to incoporate these additional unsafe statments.
SYSTEM VARIABLE NAME SQL_MAX_JOIN_SI
BACKGROUND:
ER_TOO_BIG_SELECT refers to SQL_MAX_JOIN_SIZE, which is the
old name for MAX_JOIN_SIZE.
FIX:
Support for old name SQL_MAX_JOIN_SIZE is removed in MySQL 5.6
and is renamed as MAX_JOIN_SIZE.So the errmsg.txt
and mysql.cc files have been updated and the corresponding result
files have also been updated.
WITH MYSQL_REFRESH()
reset_slave_info.all was not initialized.
We fix this by setting lex->reset_slave_info.all= false in
the lex_start routine, which is called before every statement.
Connection of slave to master using a replication account which authenticates
with an external plugin was not possible.
Fixed by making sure that the CLIENT_PLUGIN_AUTH capability is set when client connects using mysql_real_connect(). Also, a plugin-dir path used by client library to locate authentication plugins is set based on the analogous server setting. This is done in connect_to_master() function before a call to mysql_real_connect().
FROM OK PACKET
There's no reliable way (without knowing the protocol variants that each
plugin pair implements) to find out when does the authentication exchange
end.
The server is changed to send all the extra authentication packets that
server plugins need to send prefixed with the \x1 command.
This fix was accidentally pushed to mysql-5.1 after the 5.1.59 clone-off in
bzr revision id marko.makela@oracle.com-20110829081642-z0w992a0mrc62s6w
with the fix of Bug#12704861 Corruption after a crash during BLOB update
but not merged to mysql-5.5 and upwards.
In the Barracuda formats, the clustered index record no longer
contains a prefix of off-page columns. Because of this, the undo log
must contain these prefixes, so that purge and multi-versioning will
continue to work. However, this also means that an undo log record can
become too big to fit in an undo log page. (It is a limitation of the
undo log that undo records cannot span across multiple pages.)
In case the checks for undo log size fail when CREATE TABLE or CREATE
INDEX is executed, we need a fallback that blocks a modification
operation when the undo log record would exceed the maximum size.
trx_undo_free_last_page_func(): Renamed from trx_undo_free_page_in_rollback().
Define the trx_t parameter only in debug builds.
trx_undo_free_last_page(): Wrapper for trx_undo_free_last_page_func().
Pass the trx_t parameter only in debug builds.
trx_undo_truncate_end_func(): Renamed from trx_undo_truncate_end().
Define the trx_t parameter only in debug builds. Rewrite a for(;;) loop
as a while loop for clarity.
trx_undo_truncate_end(): Wrapper for from trx_undo_truncate_end_func().
Pass the trx_t parameter only in debug builds.
trx_undo_erase_page_end(): Return TRUE if the page was non-empty
to begin with. Refuse to erase empty pages.
trx_undo_report_row_operation(): If the page for which the undo log
was too big was empty, free the undo page and return DB_TOO_BIG_RECORD.
rb:749 approved by Inaam Rana
GROUPING BY FUNCTIONS.... (PART
The bug was introduced in a patch for bug 49897.
Problem: The assertion inserted by the original patch to guard against
zero-lenght sort keys during merge phase triggers also when the whole
set fits in memory.
Fix: Move assert so that it does not trigger if the whole set is in
memory.
Converting the number zero to binary and back yielded the number zero,
but with no digits, i.e. zero precision.
This made the multiply algorithm go haywire in various ways.
Suppress the known warnings generated by filesort().
The real fix belongs to worklog 1509:
Pack values of non-sorted fields in the sort buffer
(which is basically the same issue, but in an optimization context:
We are writing the entire sort buffer to disk,
including un-used space for varchar columns.)
Background: Backporting fix for BUG 11752963 to Mysql5.1 branch.
Problem: Fix of bug 11752963 was only available for trunk and 5.5 branch.
Partial fix has been pushed to 5.1 branch as well.
Fix: backporting the fixes of bug 11752963 to 5.1 branch.
1. Made all major changes to make 5.1 branch in line with 5.5 and the trunk.
2. skipped the partial patch that was already applied to the 5.1 branch.
Blind attempt to fix BUG 12881278 - MAIN.MYISAM TEST FAILS ON LINUX
The printed text is truncated on char 63:
"MySQL thread id 1236, OS thread handle 0x7ff187b96700, query id"
still I do not understand how this truncation could have caused the
main.myisam failure but anyway - the buffer needs to be increased.
CRASHES SERVER
Flushing of MERGE table or one of its child tables, which was
locked by flushing thread using LOCK TABLES, might have caused
crashes or assertion failures if the thread failed to reopen
child or parent table.
Particularly, this might have happened when another connection
killed this FLUSH TABLE statement/connection.
Also this problem might have occurred when we failed to reopen
MERGE table or one of its children when executing DDL statement
under LOCK TABLES.
The problem was caused by the fact that reopen_tables() might
have failed to reopen child table but still tried to reopen,
reattach children for and re-lock its parent. Vice versa it
might have failed to reopen parent but kept references from
children to parent around. Since reopen_tables() closes table
it has failed to reopen and therefore frees all associated
memory such dangling references led to crashes when followed.
This patch solves this problem by ensuring that we always close
parent table and all its children if we fail to reopen this
table or one of its children. Same happens if we fail to reattach
children to parent.
Affects 5.1 only.
Also addressed issues in bug #11745133, where we could mark a table
corrupted instead of crashing the server when found a corrupted buffer/page
if the table created with innodb_file_per_table on.
to mysql-5.5.16-release.
Original revision:
# revision-id: dmitry.lenev@oracle.com-20110811155849-feyt3h7tj48padiu
# parent: tatjana.nuernberg@oracle.com-20110811120945-c6x9a5d2du8s9oj2
# committer: Dmitry Lenev <Dmitry.Lenev@oracle.com>
# branch nick: mysql-5.5-12828477
# timestamp: Thu 2011-08-11 19:58:49 +0400
# message:
# Fix for bug #12828477 - "MDL SUBSYSTEM CREATES BIG OVERHEAD
# FOR CERTAIN QUERIES TO INFORMATION_SCHEMA".
#
# The problem was that metadata locking subsystem introduced
# too much overhead for queries to I_S which were processed by
# opening only .FRM or .TRG files and had to scanned a lot of
# tables (e.g. SELECT COUNT(*) FROM I_S.TRIGGERS was affected).
# The same effect was not observed for similar queries which
# performed full-blown table open in order to fill I_S table.
#
# The problem stemmed from the fact that in case when I_S
# implementation opened only .FRM or .TRG file for each table
# processed it didn't release metadata lock it has acquired on
# the table after finishing its processing. As result, list
# of acquired metadata locks were growing until the end of
# statement. Since acquisition of each new lock required
# search in the list of already acquired locks performance
# degraded.
#
# The same effect is not observed when I_S implementation
# performs full-blown table open for each table being
# processed, as in the latter cases metadata lock on the
# table is released right after table processing.
#
# This fix addressed the problem by ensuring that I_S
# implementation releases metadata lock after processing
# the table in both cases of full-blown table open and in
# case when only .FRM or .TRG file is read.
FOR CERTAIN QUERIES TO INFORMATION_SCHEMA".
The problem was that metadata locking subsystem introduced
too much overhead for queries to I_S which were processed by
opening only .FRM or .TRG files and had to scanned a lot of
tables (e.g. SELECT COUNT(*) FROM I_S.TRIGGERS was affected).
The same effect was not observed for similar queries which
performed full-blown table open in order to fill I_S table.
The problem stemmed from the fact that in case when I_S
implementation opened only .FRM or .TRG file for each table
processed it didn't release metadata lock it has acquired on
the table after finishing its processing. As result, list
of acquired metadata locks were growing until the end of
statement. Since acquisition of each new lock required
search in the list of already acquired locks performance
degraded.
The same effect is not observed when I_S implementation
performs full-blown table open for each table being
processed, as in the latter cases metadata lock on the
table is released right after table processing.
This fix addressed the problem by ensuring that I_S
implementation releases metadata lock after processing
the table in both cases of full-blown table open and in
case when only .FRM or .TRG file is read.
BUG #11754979 - 46675: ON DUPLICATE KEY UPDATE AND UPDATECOUNT() POSSIBLY WRONG
The mysql_affected_rows() client call returns 3 instead of 2 on
INSERT ... ON DUPLICATE KEY UPDATE query with a duplicated key value.
The fix for the old bug #29692 was incomplete: unnecessary double
increment of "touched" rows still happened.
This bugfix removes:
1) unneeded increment of "touched" rows and
2) useless double resetting of auto-increment value.
There is an optimization of DISTINCT in JOIN::optimize()
which depends on THD::used_tables value. Each SELECT statement
inside SP resets used_tables value(see mysql_select()) and it
leads to wrong result. The fix is to replace THD::used_tables
with LEX::used_tables.
The problem is that TIME_FUZZY_DATE is explicitly used for get_arg0_date()
function in Item_date_typecast::get_date method. The fix is to use real
fuzzy_date value.
In 5.5, REFRESH SLAVE is used as an alias for RESET SLAVE and
was removed in 5.6. Reseting a slave through REFRESH SLAVE was
causing errors in the valgrind platform since reset_slave_info
was undefined.
To fix the problem, we have set reset_slave_info while calling
REFRESH SLAVE.
SHOW ALL PROBLEMS FOR MERGE TABLE COMPLIANCE IN 5.1".
The problem was that CHECK/REPAIR TABLE for a MERGE table which
had several children missing or in wrong engine reported only
issue with the first such table in its result-set. While in 5.0
this statement returned the whole list of problematic tables.
Ability to report problems for all children was lost during
significant refactorings of MERGE code which were done as part
of work on 5.1 and 5.5 releases.
This patch restores status quo ante refactorings by changing
code in such a way that:
1) Failure to open child table due to its absence during CHECK/
REPAIR TABLE for a MERGE table is not reported immediately
when its absence is discovered in open_tables(). Instead
handling/error reporting in such a situation is postponed
until the moment when children are attached.
2) Code performing attaching of children no longer stops when
it encounters first problem with one of the children during
CHECK/REPAIR TABLE. Instead it continues iteration through
the child list until all problems caused by child absence/
wrong engine are reported.
Note that even after this change problem with mismatch of
child/parent definition won't be reported if there is also
another child missing, but this is how it was in 5.0 as well.
