Improve the range estimation algorithm.
Previously:
For a given level the algo knows the number of pages in the requested range and the n
With this change:
Same idea, but peek a few (10) of the intermediate pages to get a better estimate of
In the bug report one of the examples has a btree with a snippet of the leaf level li
page1(899 records), page2(1 record), page3(1 record), page4(1 record)
so when trying to estimate, the previous algo, assumed there are average (899+1)/2=45
Fix Bug#53761 RANGE estimation for matched rows may be 200 times different
Improve the range estimation algorithm.
Previously:
For a given level the algo knows the number of pages in the requested range
and the number of records on the leftmost and the rightmost page. Then it
assumes all pages in between contain the average between the two border pages
and multiplies this average number by the number of intermediate pages.
With this change:
Same idea, but peek a few (10) of the intermediate pages to get a better
estimate of the average number of records per page. If there are less than 10
intermediate pages then all of them will be scanned and the result will be
precise, not an estimation.
In the bug report one of the examples has a btree with a snippet of the leaf
level like this:
page1(899 records), page2(1 record), page3(1 record), page4(1 record)
so when trying to estimate, the previous algo, assumed there are average
(899+1)/2=450 records per page which went terribly wrong. With this change
page2 and page3 will be read and the exact number of records will be returned.
Approved by: Sunny (rb://401)
example files)
The system variable 'thread_concurrency' has been
(re-)enabled on all platforms, to prevent startup
errors.
'thread_concurrency' is unused and has no effect,
on any platform, in MySQL 5.1 and later versions. It
will be deprecated, and removed, in context of
worklog WL#5265
locks on the table
Fixing the partitioning specifics after TRUNCATE TABLE in
bug-42643 was fixed.
Reorganize of code to decrease the size of the giant switch
in mysql_execute_command, and to prepare for future parser
reengineering. Moved code into Sql_statement objects.
Updated patch according to davi's review comments.
pushdown.
NDB supports only a limited set of item nodes for use in engine condition
pushdown. Because of this adding cache for const expression effectively
disabled this optimization.
The ndb_serialize_cond function is extended to support Item_cache and treat
it as a constant values.
A helper function called ndb_serialize_const is added. It is used to create
Ndb_cond value node from given const item.
The problem was that SHOW CREATE EVENT released all metadata locks
held by the current transaction. This made any exisiting savepoints
invalid, triggering the assert when ROLLBACK TO SAVEPOINT later
was executed.
This patch fixes the problem by making sure SHOW CREATE EVENT only
releases metadata locks acquired by the statement itself.
Test case added to event_trans.test.
corruption on ADD PARTITION and LOCK TABLE
Bug#53770: Server crash at handler.cc:2076 on
LOAD DATA after timed out COALESCE PARTITION
5.5 fix for:
Bug#51042: REORGANIZE PARTITION can leave table in an
inconsistent state in case of crash
Needs to be back-ported to 5.1
5.5 fix for:
Bug#50418: DROP PARTITION does not interact with
transactions
Main problem was non-persistent operations done
before meta-data lock was taken (53770+53676).
And 53676 needed to keep the table/partitions opened and locked
while copying the data to the new partitions.
Also added thorough tests to spot some additional bugs
in the ddl_log code, which could result in bad state
between the .frm and partitions.
Collapsed patch, includes all fixes required from the reviewers.
"MySQL server is not restarted properly after RPM upgrade"
The problem is that with the general spec file cleanup and
alignment we also did a name change, dropping the "-community"
part from the package file name.
As a result of this, RPM (some versions of it) will report
file conflicts, because it considers this name difference
to imply different packages.
To avoid this, the spec file explicitly "obsoletes" the old
packages (with "-community" in the file name).
Now, RPM will first install these packages and the remove the
old ones, and part of that removal is running the "%preun"
section which stops the server and uninstalls the service
(removes the symlinks to "/etc/init.d/mysql" from the run
level directories).
This stop/uninstall will affect the new server!
The fix is to define a "%triggerpostun" in this spec file
which will watch for removal of the "-community" server.
If this is done (as part of this install/upgrade), the
trigger code will re-install the service and restart the
server process.
In addition, the "sleep" calls after starting the server
have been cleaned up: Rather than doing 2* "sleep 2",
it is now 1 "sleep 5".
feature
The test for bug no 50939 was put in range.test which isn't such a good idea
since it requires partitioning. Fixed by moving the test case to
partitioning_range.test.
A label statement needs to be followed by at least
one primary expression. If built without
WITH_PARTITION_STORAGE_ENGINE set, the block would
be empty.
Added ';' as a dummy statement to fix it.
After BUG#36649, warnings for sub-statements are cleared when a
new sub-statement is started. This is problematic since it suppresses
warnings for unsafe statements in some cases. It is important that we
always give a warning to the client, because the user needs to know
when there is a risk that the slave goes out of sync.
We fixed the problem by generating warning messages for unsafe statements
while returning from a stored procedure, function, trigger or while
executing a top level statement.
We also started checking unsafeness when both performance and log tables are
used. This is necessary after the performance schema which does a distinction
between performance and log tables.
with open HANDLER
This patch changes the code for table renames to not drop metadata
locks. Since table renames are done as a part of ALTER DATABASE ...
UPGRADE, dropping metadata locks in the middle of execution can
result in wrong binlog order since it means that no locks are held
when the binlog is written to.
The RENAME TABLE statement is unafffected since it auto commits and
therefore already drops metadata locks at the end of execution.
This patch also reverts the regression test for Bug#48940 back to
its original version. The test was temporarily changed due to the
issue mentioned above.
Reduce ibuf_mutex and ibuf_pessimistic_insert_mutex contention further.
Protect ibuf->empty by the insert buffer root page latch, not ibuf_mutex.
ibuf_tree_root_get(): Assert that ibuf_mutex is owned by the
caller. Assert that the stamped page number is correct. Assert that
ibuf->empty agrees with the root page.
ibuf_size_update(): Do not update ibuf->empty.
ibuf_init_at_db_start(): Update ibuf->empty while holding the root page latch.
ibuf_add_free_page(): Return TRUE/FALSE instead of DB_SUCCESS/DB_STRONG_FAIL.
ibuf_remove_free_page(): Release ibuf_pessimistic_insert_mutex as
early as possible.
ibuf_contract_ext(): Rely on a dirty read of ibuf->empty, unless the
server is being shut down. Never acquire ibuf_mutex. Eliminate n_stored.
ibuf_contract_after_insert(): Never acquire ibuf_mutex. Perform dirty
reads of ibuf->size and ibuf->max_size.
ibuf_insert_low(): Only acquire ibuf_mutex for mode==BTR_MODIFY_TREE.
Perform dirty reads of ibuf->size and ibuf->max_size. Update
ibuf->empty while holding the root page latch.
ibuf_delete_rec(): Update ibuf->empty while holding the root page latch.
ibuf_is_empty(): Release ibuf_mutex earlier.
Fix by adding "DEPENDS gen_lex_hash" to ADD_CUSTOM_COMMAND(),
so it regenerates lex_hash.h whenever gen_lex_lash changes.
Also, make sql dependent on GenServerSource to avoid concurrent
generation of lex_hash.h (once for sql , and in parallel for embedded)
Remove acquisition of LOCK_open around file system operations,
since such operations are now protected by metadata locks.
Rework table discovery algorithm to not require LOCK_open.
No new tests added since all MDL locking operations are covered
in lock.test and mdl_sync.test, and as long as these tests
pass despite the increased concurrency, consistency must be
unaffected.
