fixed several defects in the greedy optimization:
1) The greedy optimizer calculated the 'compare-cost' (CPU-cost)
for iterating over the partial plan result at each level in
the query plan as 'record_count / (double) TIME_FOR_COMPARE'
This cost was only used locally for 'best' calculation at each
level, and *not* accumulated into the total cost for the query plan.
This fix added the 'CPU-cost' of processing 'current_record_count'
records at each level to 'current_read_time' *before* it is used as
'accumulated cost' argument to recursive
best_extension_by_limited_search() calls. This ensured that the
cost of a huge join-fanout early in the QEP was correctly
reflected in the cost of the final QEP.
To get identical cost for a 'best' optimized query and a
straight_join with the same join order, the same change was also
applied to optimize_straight_join() and get_partial_join_cost()
2) Furthermore to get equal cost for 'best' optimized query and a
straight_join the new code substrcated the same '0.001' in
optimize_straight_join() as it had been already done in
best_extension_by_limited_search()
3) When best_extension_by_limited_search() aggregated the 'best' plan a
plan was 'best' by the check :
'if ((search_depth == 1) || (current_read_time < join->best_read))'
The term '(search_depth == 1' incorrectly caused a new best plan to be
collected whenever the specified 'search_depth' was reached - even if
this partial query plan was more expensive than what we had already
found.
sql/sql_insert.cc:
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
******
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
sql/sql_table.cc:
small cleanup
******
small cleanup
Applied the fix for bug #47217 from the mysql-6.0 codebase.
The patch adds not null predicates generated for the left parts
of the equality predicates used for ref accesses. This is done
for such predicates both in where conditions and on conditions.
For the where conditions the not null predicates were generated
but in 5.0/5.1 they actually never were used due to some lame
merge from 4.1 to 5.0. The fix for bug #47217 made these
predicates to be used in the condition pushed to the tables.
Yet only this patch generates not null predicates for equality
predicated from on conditions of outer joins.
This patch introduces a performance regression that can be
observed on a test case from null_key.test. The regression
will disappear after the fix for bug #57024 from mariadb-5.1
is pulled into mariadb-5.3.
The patch contains many changes in the outputs of the EXPLAIN
commands since generated not null predicates are considered as
parts of the conditions pushed to join tables and may add
'Usingwhere' in some rows of EXPLAINs where there used
to be no such comments.
Add deprecation warning when variable optimizer_search_depth is given
the value 63.
mysql-test/r/greedy_optimizer.result
Updated with warning text.
mysql-test/r/mysqld--help-notwin.result
Updated with warning from mysqld --help --verbose.
mysql-test/r/mysqld--help-win.result
Updated with warning from mysqld --help --verbose.
sql/sys_vars.cc
Added an update check function to the constructor invocation for
the optimizer_search_depth variable. The function emits a
warning message for the value 63.
The greedy optimizer tracks the current level of nested joins and the position
inside these by setting and maintaining a state that's global for the whole FROM
clause.
This state was correctly maintained inside the selection of the next partial plan
table (in best_extension_by_limited_search()).
greedy_search() also moves the current position by adding the last partial match
table when there's not enough tables in the partial plan found by
best_extension_by_limited_search().
This may require update of the global state variables that describe the current
position in the plan if the last table placed by greedy_search is not a top-level
join table.
Fixed by updating the state after placing the partial plan table in greedy_search()
in the same way this is done on entering the best_extension_by_limited_search().
Fixed the signature of the function called to update the state :
check_interleaving_with_nj
mysql-test/r/greedy_optimizer.result:
Bug #38795: test case
mysql-test/t/greedy_optimizer.test:
Bug #38795: test case
sql/sql_select.cc:
Bug #38795: correctly update current position when placing
the next partial plan table in greedy_search().
- Renamed "Using join cache" to "Using join buffer".
- "Using join buffer" is now printed on the last
table that "reads" from the join buffer cache.
mysql-test/r/archive_gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/compress.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ctype_utf8.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/derived.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/distinct.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/func_group.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/func_group_innodb.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/greedy_optimizer.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/group_by.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/group_min_max.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/index_merge_myisam.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/information_schema.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/innodb_gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/innodb_mysql.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/join.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/join_nested.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/key_diff.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/myisam.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ndb_condition_pushdown.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ndb_gis.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/range.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/row.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/select.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ssl.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/ssl_compress.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/subselect.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/subselect3.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/union.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
mysql-test/r/view.result:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
sql/sql_select.cc:
Bug #27531: renamed "Using join cache" to "Using join buffer"
and moved to the last table in the batch.
- added join cache indication in EXPLAIN (Extra column).
- prefer filesort over full scan over
index for ORDER BY (because it's faster).
- when switching from REF to RANGE because
RANGE uses longer key turn off sort on
the head table only as the resulting
RANGE access is a candidate for join cache
and we don't want to disable it by sorting
on the first table only.
mysql-test/r/archive_gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/compress.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ctype_utf8.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/derived.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/distinct.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/func_group.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/func_group_innodb.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/greedy_optimizer.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/group_by.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/group_min_max.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/index_merge_myisam.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/information_schema.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/innodb_gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/innodb_mysql.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/join.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/join_nested.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/key_diff.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/myisam.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/ndb_condition_pushdown.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/ndb_gis.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/range.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/row.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/select.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ssl.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ssl_compress.result:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over index for ORDER BY.
mysql-test/r/subselect.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/subselect3.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/union.result:
bug #27531: join cache in EXPLAIN
mysql-test/r/view.result:
bug #27531: join cache in EXPLAIN
sql/sql_select.cc:
bug #27531:
- join cache in EXPLAIN.
- prefer filesort over full scan over
index for ORDER BY.
- disable sorting on the first table only
when switching from REF to RANGE.
mysql-test/r/greedy_optimizer.result:
Adjusted query costs accordingly.
sql/sql_select.cc:
Someone added this 0.001 cost factor to best_extension_by_limited_search(), but forgot to
add it to the old version of the optimizer - find_best().
mysql-test/r/connect.result:
standard values for table type in SHOW TABLES
mysql-test/r/ctype_recoding.result:
standard values for table type in SHOW TABLES
mysql-test/r/drop.result:
standard values for table type in SHOW TABLES
mysql-test/r/greedy_optimizer.result:
fixed results
mysql-test/r/lowercase_table.result:
standard values for table type in SHOW TABLES
mysql-test/r/ps_1general.result:
standard values for table type in SHOW TABLES
mysql-test/r/rename.result:
standard values for table type in SHOW TABLES
mysql-test/r/rpl000009.result:
standard values for table type in SHOW TABLES
mysql-test/r/rpl_error_ignored_table.result:
standard values for table type in SHOW TABLES
mysql-test/r/select.result:
standard values for table type in SHOW TABLES
mysql-test/r/system_mysql_db.result:
standard values for table type in SHOW TABLES
mysql-test/r/view.result:
standard values for table type in SHOW TABLES
sql/sql_show.cc:
standard values for table type in SHOW TABLES
debugging trap
consisting of pos-review fixes and improvements.
mysql-test/r/distinct.result:
Adjusted to account for pre-sorting of tables before optimiziation.
mysql-test/r/func_group.result:
Adjusted to account for pre-sorting of tables before optimiziation.
mysql-test/r/greedy_optimizer.result:
- Adjusted to account for pre-sorting of tables before optimiziation.
- Removed unnecessary test.
- More comments.
mysql-test/r/select.result:
- Adjusted to account for pre-sorting of tables before optimiziation.
mysql-test/t/greedy_optimizer.test:
- Adjusted to account for pre-sorting of tables before optimiziation.
- Removed unnecessary test.
- More comments.
sql/mysql_priv.h:
Moved function print_plan() to sql_test.cc
sql/sql_select.cc:
- Simplified the recursion in best_extension_by_limited_search()
and aligned it with its pseudo-code.
- Renamed functions to better reflect their semantics.
- Post-review changes of function specifications.
- Moved function print_plan() to sql_test.cc.
sql/sql_test.cc:
Moved function print_plan() to sql_test.cc
mysql-test/r/subselect.result:
Table pre-sorting before optimization makes the optimizer select a different plan, this change fixes the plan.
sql/mysql_priv.h:
Added new status variable last_query_cost that contains the cost of the last compiled query.
sql/mysqld.cc:
* Added new system variable 'plan_search_depth' to control the exhaustiveness of the search for an optimal query plan.
* Added new system variable 'heuristic' to control the use of query optimization heuristic.
* Added new status variable 'last_query_cost' that contains the cost of the last compiled query.
sql/set_var.cc:
* Added new system variable 'plan_search_depth' to control the exhaustiveness of the search for an optimal query plan.
* Added new system variable 'heuristic' to control the use of query optimization heuristic.
sql/sql_class.h:
* Added new system variable 'plan_search_depth' to control the exhaustiveness of the search for an optimal query plan.
* Added new system variable 'heuristic' to control the use of query optimization heuristic.
sql/sql_select.cc:
Added a combined greedy/exhaustive query optimization algorithm.
* The greedy search algorithm is implemented in function 'greedy_search'.
* The exhaustive search with controlled search depth is implemented in function 'find_best_limited_depth', a modification of 'find_best'.
* The selection of the best access path and its cost computation is factored out from 'find_best' into function 'best_access_path'.
* In addition:
- added pre-sorting for the query tables before they get optimized
- factored out the optimization of STRAIGHT_JOIN into a separate procedure
sql/sql_select.h:
Added new field to st_position to support the greedy optimizer.
Added a comment to class JOIN.
sql/sql_show.cc:
Added a case to 'mysqld_show' to print double status variables.
sql/structs.h:
Added a new type of status variables SHOW_DOUBLE
BitKeeper/etc/logging_ok:
Logging to logging@openlogging.org accepted
