INDEX_READ_MAP HAD NO MATCH
If index_read_map is called for exact search and no matching records
exists it will position the cursor on the next record, but still having the
relative position to BTR_PCUR_ON.
This will make a call for index_next to read yet another next record,
instead of returning the record the cursor points to.
Fixed by setting pcur->rel_pos = BTR_PCUR_BEFORE if an exact
[prefix] search is done, but failed.
Also avoids optimistic restoration if rel_pos != BTR_PCUR_ON,
since btr_cur may be different than old_rec.
rb#3324, approved by Marko and Jimmy
WITH A VARIABLE AND ORDER BY
Bug#16035412 MYSQL SERVER 5.5.29 WRONG SORTING USING COMPLEX INDEX
This is a fix for a regression introduced by Bug#12667154:
Bug#12667154 attempted to fix a performance problem with subqueries
that did filesort. For doing filesort, the optimizer creates a quick
select object to use when building the sort index. This quick select
object was deleted after the first call to create_sort_index(). Thus,
for queries where the subquery was executed multiple times, the quick
object was only used for the first execution. For all later executions
of the subquery, filesort used a complete table scan for building the
sort index. The fix for Bug#12667154 tried to fix this by not deleting
the quick object after the first execution of create_sort_index() so
that it would be re-used for building the sort index by the following
executions of the subquery.
This regression introduced in Bug#12667154 is that due to not deleting
the quick select object after building the sort index, the quick
object could in some cases be used also during the second phase of the
execution of the subquery instead of using the created sort
index. This caused wrong results to be returned.
The fix for this issue is to delete the reference to the select object
after it has been used in create_sort_index(). In this way the select
and quick objects will not be available when doing the second phase
of the execution of the select operation. To ensure that the select
object can be re-used for the following executions of the subquery
we make a copy of the select pointer. This is used for restoring the
select object after the select operation is completed.
mysql-test/suite/innodb/r/innodb_mysql.result:
Changed explain output: The explain now contains "Using where" since we
have restored the select pointer after doing the filesort operation.
sql/sql_select.cc:
Change create_sort_index() so that it always sets the pointer to
the select object to NULL. This is done in order to avoid that the
select->quick object can be used when execution the main part of
the select operation.
sql/sql_select.h:
New member in JOIN_TAB: saved_select. Used by create_sort_index to
make a backup copy of the select pointer.
btr_lift_page_up() writes wrong page number (different by -1) for upper than father page.
But in almost all of the cases, the father page should be root page, no upper
pages. It is very rare path.
In addition the leaf page should not be lifted unless the father page is root.
Because the branch pages should not become the leaf pages.
rb://1336 approved by Marko Makela.
btr_lift_page_up() writes wrong page number (different by -1) for upper than father page.
But in almost all of the cases, the father page should be root page, no upper
pages. It is very rare path.
In addition the leaf page should not be lifted unless the father page is root.
Because the branch pages should not become the leaf pages.
rb://1336 approved by Marko Makela.
SECONDARY INDEX UPDATES MAKE CONSISTENT READS DO O(N^2) UNDO PAGE
LOOKUPS (honoring kill query while accessing sec_index)
If secondary index is being used for select query evaluation and this
query is operating with consistent read snapshot it might take good time for
secondary index to return back control to mysql as MVCC would kick in.
If user issues "kill query <id>" while query is actively accessing
secondary index it will not be honored as there is no hook to check
for this condition. Added hook for this check.
-----
Parallely secondary index taking too long to evaluate for consistent
read snapshot case is being examined for performance improvement. WL#6540.
SECONDARY INDEX UPDATES MAKE CONSISTENT READS DO O(N^2) UNDO PAGE
LOOKUPS (honoring kill query while accessing sec_index)
If secondary index is being used for select query evaluation and this
query is operating with consistent read snapshot it might take good time for
secondary index to return back control to mysql as MVCC would kick in.
If user issues "kill query <id>" while query is actively accessing
secondary index it will not be honored as there is no hook to check
for this condition. Added hook for this check.
-----
Parallely secondary index taking too long to evaluate for consistent
read snapshot case is being examined for performance improvement. WL#6540.
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.
Backport from mysql-5.6 the fix
(revision-id sunny.bains@oracle.com-20120315045831-20rgfa4cozxmz7kz)
Bug#13839886 - CRASH IN INNOBASE_NEXT_AUTOINC
The assertion introduce in the fix for Bug#13817703
is too strong, a negative number can be greater
than the column max value, when the column value is
a negative number.
rb://978 Approved by Jimmy Yang.
rb:1236 approved by Marko Makela
Backporting the WL#5716, "Information schema table for InnoDB
buffer pool information". Backporting revisions 2876.244.113,
2876.244.102 from mysql-trunk.
rb://1177 approved by Jimmy Yang.
BY A CONCURRENT TRANSACTIO
The member function QUICK_RANGE_SELECT::init_ror_merged_scan() performs
a table handler clone. Innodb does not provide a clone operation.
The ha_innobase::clone() is not there. The handler::clone() does not
take care of the ha_innobase->prebuilt->select_lock_type. Because of
this what happens is that for one index we do a locking read, and
for the other index we were doing a non-locking (consistent) read.
The patch introduces ha_innobase::clone() member function.
It is implemented similar to ha_myisam::clone(). It calls the
base class handler::clone() and then does any additional operation
required. I am setting the ha_innobase->prebuilt->select_lock_type
correctly.
rb://1060 approved by Marko
UNHANDLED, CONFUSING ERROR
The main confusion with the error message is that "it
implies that your data dictionary may now be out of
sync". This patch will remove the unwanted and the
misleading error message by not doing an unnecessary
operation in the error handling code.
rb://980 approved by: Dmitry Lenev
Fix the calculation of the next autoinc value when offset > 1. Some of the
results have changed due to the changes in the allocation calculation. The
new calculation will result in slightly bigger gaps for bulk inserts.
rb://866 Approved by Jimmy Yang.
Backported from mysql-trunk (5.6)
truncating, inserting the same set of rows. When a table is
re-created with the same set of rows, the data file size must
not grow.
rb:968
Approved by Marko.
There are two threads. In one thread, dml operation is going on
involving cascaded update operation. In another thread, alter
table add foreign key constraint is happening. Under these
circumstances, it is possible for the dml thread to access a
dict_foreign_t object that has been freed by the ddl thread.
The debug sync test case provides the sequence of operations.
Without fix, the test case will crash the server (because of
newly added assert). With fix, the alter table stmt will return
an error message.
Backporting the fix from MySQL 5.5 to 5.1
rb:961
rb:947
There are two threads. In one thread, dml operation is going on
involving cascaded update operation. In another thread, alter
table add foreign key constraint is happening. Under these
circumstances, it is possible for the dml thread to access a
dict_foreign_t object that has been freed by the ddl thread.
The debug sync test case provides the sequence of operations.
Without fix, the test case will crash the server (because of
newly added assert). With fix, the alter table stmt will return
an error message.
rb:947
approved by Jimmy Yang
The actual Bug#11754376 does not exist in MySQL 5.5 because at startup
we drop entries for temporary tables from InnoDB dictionary cache (only
if ROW_FORMAT is not REDUNDANT). But nevertheless the bug in
normalize_table_name_low() is present so we fix it.
GRACEFUL SHUTDOWN
During startup mysql picks up .frm files from the tmpdir directory and
tries to drop those tables in the storage engine.
The problem is that when tmpdir ends in / then ha_innobase::delete_table()
is passed a string like "/var/tmp//#sql123", then it wrongly normalizes it
to "/#sql123" and calls row_drop_table_for_mysql() which of course fails
to delete the table entry from the InnoDB dictionary cache.
ha_innobase::delete_table() returns an error but nevertheless mysql wipes
away the .frm file and the entry in the InnoDB dictionary cache remains
orphaned with no easy way to remove it.
The "no easy" way to remove it is to create a similar temporary table again,
copy its .frm file to tmpdir under "#sql123.frm" and restart mysqld with
tmpdir=/var/tmp (no trailing slash) - this way mysql will pick the .frm file
after restart and will try to issue drop table for "/var/tmp/#sql123"
(notice do double slash), ha_innobase::delete_table() will normalize it to
"tmp/#sql123" and row_drop_table_for_mysql() will successfully remove the
table entry from the dictionary cache.
The solution is to fix normalize_table_name_low() to normalize things like
"/var/tmp//table" correctly to "tmp/table".
This patch also adds a test function which invokes
normalize_table_name_low() with various inputs to make sure it works
correctly and a mtr test that calls this test function.
Reviewed by: Marko (http://bur03.no.oracle.com/rb/r/929/)
If we meet DB_TOO_MANY_CONCURRENT_TRXS during the execution tab_create_graph from row_create_table_for_mysql(), .ibd file for the table should be created already but was not deleted for the error handling.
rb:875 approved by Jimmy Yang
If we meet DB_TOO_MANY_CONCURRENT_TRXS during the execution tab_create_graph from row_create_table_for_mysql(), .ibd file for the table should be created already but was not deleted for the error handling.
rb:875 approved by Jimmy Yang
CREATE TABLE bug13510739 (c INTEGER NOT NULL, PRIMARY KEY (c)) ENGINE=INNODB;
INSERT INTO bug13510739 VALUES (1), (2), (3), (4);
DELETE FROM bug13510739 WHERE c=2;
HANDLER bug13510739 OPEN;
HANDLER bug13510739 READ `primary` = (2);
HANDLER bug13510739 READ `primary` NEXT; <-- crash
The bug is that in the particular testcase row_search_for_mysql() picked up
a delete-marked record and quit, leaving the cursor non-positioned state and
on the subsequent 'get next' call the code crashed because of the
non-positioned cursor.
In row0sel.cc (line numbers from mysql-trunk):
4653 if (rec_get_deleted_flag(rec, comp)) {
...
4679 if (index == clust_index && unique_search) {
4680
4681 err = DB_RECORD_NOT_FOUND;
4682
4683 goto normal_return;
4684 }
it quit from here, not storing the cursor position.
In contrast, if the record=2 is not found at all (e.g. sleep(1) after DELETE
to let the purge wipe it away completely) then 'get = 2' does find record=3
and quits from here:
4366 if (0 != cmp_dtuple_rec(search_tuple, rec, offsets)) {
...
4394 btr_pcur_store_position(pcur, &mtr);
4395
4396 err = DB_RECORD_NOT_FOUND;
4397 #if 0
4398 ut_print_name(stderr, trx, FALSE, index->name);
4399 fputs(" record not found 3\n", stderr);
4400 #endif
4401
4402 goto normal_return;
Another fix could be to extend the condition on line 4366 to hold only if
seach_tuple matches rec AND if rec is not delete marked.
Notice that in the above test case if we wait about 1 second somewhere after
DELETE and before 'get = 2', then the testcase does not crash and returns 4
instead. Not sure if this is the correct behavior, but this bugfix removes
the crash and makes the code return what it also returns in the non-crashing
case (if rec=2 is not found during 'get = 2', e.g. we have sleep(1) there).
Approved by: Marko (http://bur03.no.oracle.com/rb/r/863/)
The counter handler_read_key (SSV::ha_read_key_count) is incremented
incorrectly.
The mysql server maintains a per thread system_status_var (SSV)
object. This object contains among other things the counter
SSV::ha_read_key_count. The purpose of this counter is to measure the
number of requests to read a row based on a key (or the number of
index lookups).
This counter was wrongly incremented in the
ha_innobase::innobase_get_index(). The fix removes
this increment statement (for both innodb and innodb_plugin).
The various callers of the innobase_get_index() was checked to
determine if anybody must increment this counter (if they first call
innobase_get_index() and then perform an index lookup). It was found
that no caller of innobase_get_index() needs to worry about the
SSV::ha_read_key_count counter.
