Due to this bug the function SEL_IMERGE::or_sel_tree_with_checks()
could build an inconsistent merge tree if one of the SEL_TREEs in the
resulting index merge happened to contain a full key range.
This could trigger an assertion failure.
The function key_and() erroneously called SEL_ARG::increment_use_count()
when SEL_ARG::incr_refs() should had been called. This could lead to
wrong values of use_count for some SEL_ARG trees.
A bug in the code of the function key_or could lead to a situation
when performing of an OR operation for one index changes the result
the operation for another index. This bug is fixed with this patch.
Also corrected the specification and the code of the function
or_sel_tree_with_checks.
- Set the default
- Adjust the testcases so that 'new' tests are run with optimizations turned on.
- Pull out relevant tests from "irrelevant" tests and run them with optimizations on.
- Run range.test and innodb.test with both mrr=on and mrr=off
- "Using MRR" is no longer shown with range access.
- Instead, both range and BKA accesses will show one of the following:
= "Rowid-ordered scan"
= "Key-ordered scan"
= "Key-ordered Rowid-ordered scan"
depending on whether DS-MRR implementation will do scan keys in order, rowids in order,
or both.
- The patch also introduces a way for other storage engines/MRR implementations to
pass information to EXPLAIN output about the properties of employed MRR scans.
Also:
Changed the value of TIME_FOR_COMPARE_ROWID to make it the same as for MWL 21.
Changed some queries in range_vs_index_merge.test to make them generate
the same plans as earlier.
When ORing two AND-OR formulas the range optimizer could miss
a conjunct in one of AND-OR formulas in the result. If the
index merge union plan to access a table is formed by this
formula that, in general, is not inferred from the original
where/on condition,the query could return an incorrect result set.
A crash may happenin the cases when the range optimizer tried to OR
two index merge such that the second one contained less range trees
than the first one.
The bug was introduced by the patch of MWL#24:
"index_merge: fair choice between index_merge union and range access".
A crash may happenin the cases when the range optimizer tried to OR
two index merge such that the second one contained less range trees
than the first one.
The bug was introduced by the patch of MWL#24:
"index_merge: fair choice between index_merge union and range access".
that blocked building index merge plans for the queries with where
conditions of the form
(key1|2_p1=c AND range(key1_p2)) OR (key1|2_p1=c AND range(key2_p2)).
The problem was discovered by Sergey Petrunia when he reviewed the patch
for WL#24.
Added new test cases. One of them failed to produce an index merge plan
before the patch was applied.
"index_merge: fair choice between index_merge union and range access"
mysql-test/include/world.inc:
A new include file to upload the world database.
mysql-test/include/world_schema.inc:
A new include file to create tables of the world database.
mysql-test/r/index_merge_myisam.result:
The results for test cases testing the optimizations added in WL#24 for MyISAM.
mysql-test/r/range_vs_index_merge.result:
The results for test cases testing the optimizations added in WL#24 for InnoDB.
mysql-test/t/range_vs_index_merge.test:
Test cases to test the optimizations added in WL#24 for MyISAM.
mysql-test/t/range_vs_index_merge_innodb.test:
Test cases to test the optimizations added in WL#24 for InnoDB.
sql/sql_list.h:
Fixed a bug that did not allow adding a non-empty list to an empty list.
