ISSUE:
------
There can be up to MERGEBUFF2 number of sorted merge chunks,
We need enough buffer space for at least one record from
each merge chunks. If estimates are wrong(very low) and we
allocate buffer space for less than MERGEBUFF2, then we will
have issue in merge_buffers, if actual number of rows to be
sorted is bigger than estimate and external filesort is
chosen.
SOLUTION:
---------
Set number of rows to sort to be at least MERGEBUFF2.
FROM SUBSELECT
ISSUE : In function find_all_keys.
If selected row do not satisfy condition
then we call unlock_row to release the locked
row. Suppose if we have subquery in condition
and we have an innodb error during its execution.
Then we should not call the unlock_row. If the error
is because of deadlock, innodb will rollback the
transaction. And calling unlock_row without
transaction is an invalid case hence an assertion
failure.
SOLUTION : We call unlock_row only if only there is no
error occurred previously.
The solution is back ported from 5.6
defect number 14226481
WITH SORT ABORTED LEAKS FILE DESCRIPTORS
ISSUE : IO_CACHE used for index_merge quick select
is freed only on successful retrieval of all rows
from index merge.
Suppose if there is a interrupt( or failure) to
this operation of row retrieval (let it be a
KILL_QUERY signal) then we are not freeing the IO_CACHE
resources allocated by index_merge quick select.
And hence temp file associated with it is also not closed.
This lead to a file descriptor leak.
SOLUTION : As part of file sort operation now we always
free the IO_CACHE allocated by index_merge quick select.
Problem:-
We have created a table with UTF8_BIN collation.
In case, when in our query we have ORDER BY clause over a function
call we are getting result in incorrect order.
Note:the bug is not there in 5.5.
Analysis:
In 5.5, for UTF16_BIN, we have min and max multi-byte length is 2 and 4
respectively.In make_sortkey(),for 2 byte character character we are
assuming that the resultant length will be 2 byte/character. But when we
use my_strnxfrm_unicode_full_bin(), we store sorting weights using 3 bytes
per character.This result in truncated result.
Same thing happen for UTF8MB4, where we have 1 byte min multi-byte and
4 byte max multi-byte.We will accsume resultant data as 1 byte/character,
which result in truncated result.
Solution:-
use strnxfrm(means use of MY_CS_STRNXFRM macro) is used for sort, in
which the resultant length is not dependent on source length.
Description:
------------
There are 2 issues reported in the bug report,
1. One session running a "long" select, then, from the other
session, you kill that first one, while select is
running, and it receives that message "Server shutdown in
progress".
Reported Date: 02-Apr-2006
=> Looks like this isuse is already fixed in 2009 by the patch
pushed for bug28141.
2. Killing query which goes to filesort, logs error entries like:
120416 9:17:28 [ERROR] mysqld: Sort aborted: Server shutdown in
progress
120416 9:18:48 [ERROR] mysqld: Sort aborted: Server shutdown in
progress
120416 9:19:39 [ERROR] mysqld: Sort aborted: Server shutdown in
progress
Reported Date: 16-Apr-2012
=> This issue is introduced in 5.5+ versions. Fixing this issue
in this patch.
Analysis:
---------
In function "filesort()", on error we are logging error message.
To the error message, the message related THD::killed_errno is
also appeneded, if it is set.(THD::kill_errno value is obtained
by calling member function THD::killed_errno)
In the scenario mentioned in this bug report, when we kill the
connection, THD::kill_errno is set to the THD::KILL_CONNECTION.
Enum type THD::KILL_CONNECTION corressponds to value
ER_SERVER_SHUTDOWN. Because of this, "Server shutdown in ...." is
appended to the message logged.
Fix:
----
Modified code of "filesort()" function to append "KILL_QUERY"
status to error message when thread is killed and server
shutdown is not in progress.
CONSISTENT SNAPSHOT OPTION
A transaction is started with a consistent snapshot. After
the transaction is started new indexes are added to the
table. Now when we issue an update statement, the optimizer
chooses an index. When the index scan is being initialized
via ha_innobase::change_active_index(), InnoDB reports
the error code HA_ERR_TABLE_DEF_CHANGED, with message
stating that "insufficient history for index".
This error message is propagated up to the SQL layer. But
the my_error() api is never called. The statement level
diagnostics area is not updated with the correct error
status (it remains in Diagnostics_area::DA_EMPTY).
Hence the following check in the Protocol::end_statement()
fails.
516 case Diagnostics_area::DA_EMPTY:
517 default:
518 DBUG_ASSERT(0);
519 error= send_ok(thd->server_status, 0, 0, 0, NULL);
520 break;
The fix is to backport the fix of bugs 14365043, 11761652
and 11746399.
14365043 PROTOCOL::END_STATEMENT(): ASSERTION `0' FAILED
11761652 HA_RND_INIT() RESULT CODE NOT CHECKED
11746399 RETURN VALUES OF HA_INDEX_INIT() AND INDEX_INIT() IGNORED
rb://1227 approved by guilhem and mattiasj.
Bug#14530242 CRASH / MEMORY CORRUPTION IN FILESORT_BUFFER::GET_RECORD_BUFFER WITH MYISAM
This is a backport of
Bug#12694872 - VALGRIND: 18,816 BYTES IN 196 BLOCKS ARE DEFINITELY LOST
Bug#13340270: assertion table->sort.record_pointers == __null
Bug#14536113 CRASH IN CLOSEFRM (TABLE.CC) OR UNPACK (FIELD.H) ON SUBQUERY WITH MYISAM TABLES
Also:
removed and re-added test files with file-ids from trunk.
We are trying to sort a lot of text/blob fields,
so the buffer is indeed too small.
Memory available = thd->variables.sortbuff_size = 262144
min_sort_memory = param.sort_length*MERGEBUFF2 = 292245
So the decision to abort the query is correct.
filesort() calls my_error(), the error is reported.
But, since we have DELETE IGNORE ... the error is converted to a warning by
THD::raise_condition
filesort currently expects an error to be recorded in the THD diagnostics
area.
If we lift this restriction (remove the assert) we end up in the familiar
void Protocol::end_statement()
default:
DBUG_ASSERT(0);
The solution seems to be to call my_error(ME_FATALERROR) in filesort,
so that the error is propagated as an error rather than a warning.
Bug#13011410 CRASH IN FILESORT CODE WITH GROUP BY/ROLLUP
The assert in 13580775 is visible in 5.6 only,
but shows that all versions are vulnerable.
13011410 crashes in all versions.
filesort tries to re-use the sort buffer between invocations in order to save
malloc/free overhead.
The fix for Bug 11748783 - 37359: FILESORT CAN BE MORE EFFICIENT.
added an assert that buffer properties (num_records, record_length) are
consistent between invocations. Indeed, they are not necessarily consistent.
Fix: re-allocate the sort buffer if properties change.
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.
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.)
Write an additional warning message to the server log,
explaining why a sort operation is aborted.
The output in mysqld.err will look something like:
110127 15:07:54 [ERROR] mysqld: Sort aborted: Out of memory (Needed 24 bytes)
110127 15:07:54 [ERROR] mysqld: Out of sort memory, consider increasing server sort buffer size
110127 15:07:54 [ERROR] mysqld: Sort aborted: Out of sort memory, consider increasing server sort buffer size
110127 15:07:54 [ERROR] mysqld: Sort aborted: Incorrect number of arguments for FUNCTION test.f1; expected 0, got 1
If --log-warn=2 is enabled, we output information about host/user/query as well.
and 'THREAD_SAFE_CLIENT'.
As of MySQL 5.5, we no longer support non-threaded
builds. This patch removes all references to the
obsolete THREAD and THREAD_SAFE_CLIENT preprocessor
symbols. These were used to distinguish between
threaded and non-threaded builds.
This assert checks that the server does not try to send OK to the
client if there has been some error during processing. This is done
to make sure that the error is in fact sent to the client.
The problem was that view errors during processing of WHERE conditions
in UPDATE statements where not detected by the update code. It therefore
tried to send OK to the client, triggering the assert.
The bug was only noticeable in debug builds.
This patch fixes the problem by making sure that the update code
checks for errors during condition processing and acts accordingly.
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.
Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.
Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost.
The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.
Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.
This patch:
- Moves all definitions from the mysql_priv.h file into
header files for the component where the variable is
defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h
column is used for ORDER BY
Problem: filesort isn't meant for null length sort data
(e.g. char(0)), that leads to a server crash.
Fix: disregard sort order if sort data record length is 0 (nothing
to sort).
----------------------------------------------------------------------
ChangeSet@1.2571, 2008-04-08 12:30:06+02:00, vvaintroub@wva. +122 -0
Bug#32082 : definition of VOID in my_global.h conflicts with Windows
SDK headers
VOID macro is now removed. Its usage is replaced with void cast.
In some cases, where cast does not make much sense (pthread_*, printf,
hash_delete, my_seek), cast is ommited.
- In QUICK_INDEX_MERGE_SELECT::read_keys_and_merge: when we got table->sort from Unique,
tell init_read_record() not to use rr_from_cache() because a) rowids are already sorted
and b) it might be that the the data is used by filesort(), which will need record rowids
(which rr_from_cache() cannot provide).
- Fully de-initialize the table->sort read in QUICK_INDEX_MERGE_SELECT::get_next(). This fixes BUG#35477.
(bk trigger: file as fix for BUG#35478).
