Problem:
Before the ALTER TABLE statement, the array
dict_index_t::stat_n_diff_key_vals had proper values calculated
and updated. But after the ALTER TABLE statement, all the values
of this array is 0.
Because of this statistics returned by innodb_rec_per_key() is
different before and after the ALTER TABLE statement. Running the
ANALYZE TABLE command populates the statistics correctly.
Solution:
After ALTER TABLE statement, set the flag dict_table_t::stat_initialized
correctly so that the table statistics will be recalculated properly when
the table is next loaded. But note that we still don't choose the loose
index scans. This fix only ensures that an ALTER TABLE does not change
the optimizer plan.
rb://1639 approved by Marko and Jimmy.
patch to fix post push falures in pb2
BUG#15872504 - REMOVE MYSQL-TEST/INCLUDE/GET_BINLOG_DUMP_THREAD_ID.INC
=== Problem ===
The file named "mysql-test/include/get_binlog_dump_thread_id.inc" is not
used anywhere. In any case, this file does wrong things in the wrong way:
1) The file seems to assume there is only one dump thread, but there may
be many.
2) you can get this information in a much easier way using the command:
"select thread_id from threads where processlist_command="Binlog Dump";"
=== Fix ===
removed file 'mysql-test/include/get_binlog_dump_thread_id.inc'
RPL_ROW_UNTIL TIMES OUT
patch to fix post push falures in pb2
mysql-test/suite/rpl/r/rpl_row_until.result:
changes to account for the changes made in
corresponding test file.
mysql-test/suite/rpl/t/disabled.def:
disabled test in macosx
mysql-test/suite/rpl/t/rpl_row_until.test:
replaced static relayy log file by an mtr variable
which saves the name of relay log file.
=== Problem ===
The test is dependent on binlog positions and checks
to see if the command 'START SLAVE' functions correctly
with the 'UNTIL' clause added to it. The 'UNTIL' clause
is added to specify that the slave should start and run
until the SQL thread reaches a given point in the master
binary log or in the slave relay log.
The test uses hard coded values for MASTER_LOG_POS and
RELAY_LOG_POS, instead of extracting it using
query_get_value() function. There is a test
'rpl.rpl_row_until' which does the similar thing but uses
query_get_value() function to set the values of
MASTER_LOG_POS/ RELAY_LOG_POS. To be precise,
rpl.rpl_row_until is a modified version of
engines/func.rpl_row_until.test.
The use of hard coded values may lead the slave to stop at a position
which may differ from the expected position in the binlog file,
an example being the failure of engines/funcs.rpl_row_until in
mysql-5.1 given as:
"query 'select * from t2' failed. Table 'test.t2' doesn't exist".
In this case, the slave actually ran a couple of extra commands
as a result of which the slave first deleted the table and then
ran a select query on table, leading to the above mentioned failure.
=== Fix ===
1) Fixed the code for failure seen in rpl.rpl_row_until.
This test was also failing although the symptoms of
failure were different.
2) Copied the contents from rpl.rpl_row_until into
into engines/funcs.rpl.rpl_row_until.
3) Updated engines/funcs.rpl_row_until.result accordingly.
mysql-test/suite/engines/funcs/r/rpl_row_until.result:
modified to accomodate the changes in corresponding
test file.
mysql-test/suite/engines/funcs/t/disabled.def:
removed from the list of disabled tests.
mysql-test/suite/engines/funcs/t/rpl_row_until.test:
fixed rpl.rpl_row_until and copied its content to
engines/funcs.rpl_row_until. The reason being both
are same tests but rpl.rpl_row_until is an
updated version.
mysql-test/suite/rpl/t/disabled.def:
removed from the list of disabled tests.
sql/sql_repl.cc:
Added a check to catch an improper combination
of arguements passed to 'START SLAVE UNTIL'. Earlier,
START SLAVE UNTIL MASTER_LOG_FILE='master-bin.000001',
MASTER_LOG_POS=561, RELAY_LOG_POS=12;
passed. It is now detected and an error is reported.
If the setting of system variables does not allow to use join buffer
for a join query with GROUP BY <f1,...> / ORDER BY <f1,...> then
filesort is not needed if the first joined table is scanned in
the order compatible with order specified by the list <f1,...>.
fix: don't call field->val_decimal() if the field->is_null()
because the buffer at field->ptr might not hold a valid decimal value
sql/item_sum.cc:
do not call field->val_decimal() if the field->is_null()
storage/maria/ma_blockrec.c:
cleanup
storage/maria/ma_rrnd.c:
cleanup
strings/decimal.c:
typo
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.
If triggers are used for an insert/update/delete statement than the values of
all virtual columns must be computed as any of them may be used by the triggers.
If, when executing a query with ORDER BY col LIMIT n, the optimizer chose
an index-merge scan to access the table containing col while there existed
an index defined over col then optimizer did not consider the possibility
of using an alternative range scan by this index to avoid filesort. This
could cause a performance degradation if the optimizer flag index_merge was
set up to 'on'.
mysql-test/r/partition.result:
Added test case
mysql-test/t/partition.test:
Added test case
sql/ha_partition.cc:
Removed printing of not initialized variable
storage/maria/ha_maria.cc:
Don't copy variables that are not initialized
main.mysqlbinlog_row_innodb are skipped by mtr
=== Problem ===
The following tests are wrongly placed in main suite and as a
result these are not run with proper binlog format combinations.
Some are always skipped by mtr.
1) mysqlbinlog_row_myisam
2) mysqlbinlog_row_innodb
3) mysqlbinlog_row.test
4) mysqlbinlog_row_trans.test
5) mysqlbinlog-cp932
6) mysqlbinlog2
7) mysqlbinlog_base64
=== Background ===
mtr runs the tests placed in main suite with binlog format=stmt.
Those that need to be tested against binlog format=row or mixed
or more than one binlog format and require only one mysql server
are placed in binlog suite. mtr runs tests in binlog suite with
all three binlog formats(stmt,row and mixed).
=== Fix ===
1) Moved the test listed in problem section above to binlog suite.
2) Added prefix "binlog_" to the name of each test case moved.
Renamed the coresponding result files and option files accordingly.
mysql-test/extra/binlog_tests/mysqlbinlog_row_engine.inc:
include file for mysqlbinlog_row_myisam.test and
mysqlbinlog_row_myisam.test which are being moved to
binlog suite.
mysql-test/suite/binlog/r/binlog_mysqlbinlog-cp932.result:
result file for mysqlbinlog-cp932.test which is being moved to
binlog suite.
mysql-test/suite/binlog/r/binlog_mysqlbinlog2.result:
result file for mysqlbinlog2.test which is being moved to
binlog suite.
mysql-test/suite/binlog/r/binlog_mysqlbinlog_base64.result:
result file for mysqlbinlog_base64.test which is being moved to
binlog suite.
mysql-test/suite/binlog/r/binlog_mysqlbinlog_row.result:
result file for mysqlbinlog_row.test which is being moved to
binlog suite.
mysql-test/suite/binlog/r/binlog_mysqlbinlog_row_innodb.result:
result file for mysqlbinlog_row_innodb.test which is being moved to
binlog suite.
mysql-test/suite/binlog/r/binlog_mysqlbinlog_row_myisam.result:
result file for mysqlbinlog_row_myisam.test which is being moved to
binlog suite.
mysql-test/suite/binlog/r/binlog_mysqlbinlog_row_trans.result:
result file for mysqlbinlog_row_trans.test which is being moved to
binlog suite.
mysql-test/suite/binlog/t/binlog_mysqlbinlog-cp932-master.opt:
option file for mysqlbinlog-cp932.test which is being moved to
binlog suite.
mysql-test/suite/binlog/t/binlog_mysqlbinlog-cp932.test:
the test requires binlog format=stmt or mixed. Since, it was placed in
main suite earlier, it was only run with binlog format=stmt, and hence
this test was never run with binlog format=mixed.
mysql-test/suite/binlog/t/binlog_mysqlbinlog2.test:
the test requires binlog format=stmt or mixed. Since, it was placed in
main suite earlier, it was only run with binlog format=stmt, and hence
this test was never run with binlog format=mixed.
mysql-test/suite/binlog/t/binlog_mysqlbinlog_base64.test:
the test requires binlog format=row. Since, it was placed in main
suite earlier, it was only run with binlog format=stmt, and hence
this test was always skipped by mtr.
mysql-test/suite/binlog/t/binlog_mysqlbinlog_row.test:
the test requires binlog format=row. Since, it was placed in main
suite earlier, it was only run with binlog format=stmt, and hence
this test was always skipped by mtr.
mysql-test/suite/binlog/t/binlog_mysqlbinlog_row_innodb.test:
the test requires binlog format=row. Since, it was placed in main
suite earlier, it was only run with binlog format=stmt, and hence
this test was always skipped by mtr.
mysql-test/suite/binlog/t/binlog_mysqlbinlog_row_myisam.test:
the test requires binlog format=row. Since, it was placed in main
suite earlier, it was only run with binlog format=stmt, and hence
this test was always skipped by mtr.
mysql-test/suite/binlog/t/binlog_mysqlbinlog_row_trans.test:
the test requires binlog format=row. Since, it was placed in main
suite earlier, it was only run with binlog format=stmt, and hence
this test was always skipped by mtr.
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.
.. into MariaDB 5.3
Fix for Bug#12667154 SAME QUERY EXEC AS WHERE SUBQ GIVES DIFFERENT
RESULTS ON IN() & NOT IN() COMP #3
This bug causes a wrong result in mysql-trunk when ICP is used
and bad performance in mysql-5.5 and mysql-trunk.
Using the query from bug report to explain what happens and causes
the wrong result from the query when ICP is enabled:
1. The t3 table contains four records. The outer query will read
these and for each of these it will execute the subquery.
2. Before the first execution of the subquery it will be optimized. In
this case the important is what happens to the first table t1:
-make_join_select() will call the range optimizer which decides
that t1 should be accessed using a range scan on the k1 index
It creates a QUICK_RANGE_SELECT object for this.
-As the last part of optimization the ICP code pushes the
condition down to the storage engine for table t1 on the k1 index.
This produces the following information in the explain for this table:
2 DEPENDENT SUBQUERY t1 range k1 k1 5 NULL 3 Using index condition; Using filesort
Note the use of filesort.
3. The first execution of the subquery does (among other things) due
to the need for sorting:
a. Call create_sort_index() which again will call find_all_keys():
b. find_all_keys() will read the required keys for all qualifying
rows from the storage engine. To do this it checks if it has a
quick-select for the table. It will use the quick-select for
reading records. In this case it will read four records from the
storage engine (based on the range criteria). The storage engine
will evaluate the pushed index condition for each record.
c. At the end of create_sort_index() there is code that cleans up a
lot of stuff on the join tab. One of the things that is cleaned
is the select object. The result of this is that the
quick-select object created in make_join_select is deleted.
4. The second execution of the subquery does the same as the first but
the result is different:
a. Call create_sort_index() which again will call find_all_keys()
(same as for the first execution)
b. find_all_keys() will read the keys from the storage engine. To
do this it checks if it has a quick-select for the table. Now
there is NO quick-select object(!) (since it was deleted in
step 3c). So find_all_keys defaults to read the table using a
table scan instead. So instead of reading the four relevant records
in the range it reads the entire table (6 records). It then
evaluates the table's condition (and here it goes wrong). Since
the entire condition has been pushed down to the storage engine
using ICP all 6 records qualify. (Note that the storage engine
will not evaluate the pushed index condition in this case since
it was pushed for the k1 index and now we do a table scan
without any index being used).
The result is that here we return six qualifying key values
instead of four due to not evaluating the table's condition.
c. As above.
5. The two last execution of the subquery will also produce wrong results
for the same reason.
Summary: The problem occurs due to all but the first executions of the
subquery is done as a table scan without evaluating the table's
condition (which is pushed to the storage engine on a different
index). This is caused by the create_sort_index() function deleting
the quick-select object that should have been used for executing the
subquery as a range scan.
Note that this bug in addition to causing wrong results also can
result in bad performance due to executing the subquery using a table
scan instead of a range scan. This is an issue in MySQL 5.5.
The fix for this problem is to avoid that the Quick-select-object that
the optimizer created is deleted when create_sort_index() is doing
clean-up of the join-tab. This will ensure that the quick-select
object and the corresponding pushed index condition will be available
and used by all following executions of the subquery.
Check ability of index to be NULL as it made in MyISAM. UNIQUE with NULL could have several NULL entries so we have to continue even if ve have found a row.
In some rare cases when the value of the system variable join_buffer_size
was set to a number less than 256 the function JOIN_CACHE::set_constants
determined the size of an offset in the join buffer equal to 1 though
the minimal join buffer required more than 256 bytes. This could cause
a crash of the server when records from the join buffer were read.
