Fixed query plans with loose index scan degraded into index scan.
Analysis:
With MWL#89 subqueries are no longer executed and substituted during
the optimization of the outer query. As a result subquery predicates
that were previously executed and substituted by a constant before
the range optimizer were present as regular subquery predicates during
range optimization. The procedure check_group_min_max_predicates()
had a naive test that ruled out all queries with subqueries in the
WHERE clause. This resulted in worse plans with MWL#89.
Solution:
The solution is to refine the test in check_group_min_max_predicates()
to check if each MIN/MAX argument is referred to by a subquery predicate.
- Removed files specific to compiling on OS/2
- Removed files specific to SCO Unix packaging
- Removed "libmysqld/copyright", text is included in documentation
- Removed LaTeX headers for NDB Doxygen documentation
- Removed obsolete NDB files
- Removed "mkisofs" binaries
- Removed the "cvs2cl.pl" script
- Changed a few GPL texts to use "program" instead of "library"
- This allows us to detect missing my_afree() calls and also find overruns (when running with valgrind) to alloca() areas.
- Added missing my_afree() calls
- Fixed wrong call to my_afree()
include/my_sys.h:
When compiling with valgrind, change my_alloca() to use my_malloc()
mysql-test/suite/innodb/t/innodb_bug57255.test:
Speed up taste case (patch from Stewart Smith)
mysql-test/suite/innodb_plugin/t/innodb_bug57255.test:
Speed up taste case (patch from Stewart Smith)
sql/ha_partition.cc:
Removed casts from my_afree()
sql/opt_range.cc:
Add missing my_afree() calls.
storage/maria/ma_rt_split.c:
Fixed wrong parameter to my_afree()
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 semijoin=on
When setting the aggregate function as having no rows to report
the function no_rows_in_result() was calling Item_sum::reset().
However this function in addition to cleaning up the aggregate
value by calling aggregator_clear() was also adding the current
value to the aggregate value by calling aggregator_add().
Fixed by making no_rows_in_result() to call aggregator_clear()
directly.
Renamed Item_sum::reset to Item_sum::reset_and_add() to
and added a comment to avoid misinterpretation of what the
function does.
read after the last element of the array of rec_per_key
values for an index. This caused a valgrind complain and
probably could result in wrong estimates of the cardinality
of index intersections.
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.
- Fixed problem with oqgraph and 'make dist'
Note that after this merge we have a problem show in join_outer where we examine too many rows in one specific case (related to BUG#57024).
This will be fixed when mwl#128 is merged into 5.3.
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".
If a primary key was used in the index intersection for
an InnoDB database the size of the memory allocated
for the best index intersection plan was one element less
than it was needed. That could cause a memory overwrite
and a crash as a result of it.
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".
independent execution plans.
Fixed a bug in Unique::unique_add that caused a crash for a query from
index_intersect_innodb on some platforms.
Fixed two bugs in opt_range.cc that led to the choice of not the
cheapest plans for index intersections.
- Changed Cached_item_field not copy data for fields with NULL value
- In key_copy() and key_restore() don't copy data for fields with NULL value
Fixed code to avoid valgrind warnings
- Use c_ptr_safe instead of c_ptr()
Removed "QQ" from comments (QQ was ment to be used for internal comments that should be removed before pushing)
Fixed wrong alias used (from previous patch)
sql/event_db_repository.cc:
Update testing if event table is valid (to avoid valgrind errors)
sql/ha_partition.cc:
m_ordered_scan_ongoing was not initialized
Reset null bits in record to avoid valgrind errors
sql/handler.h:
Added flag if storage engine will write row verbatim and the row contains varchar or null fields
(in which case we must clear the row to avoid valgrind warnings)
sql/item_buff.cc:
Changed Cached_item_field not copy data for fields with NULL value
(Optimization and avoids valgrind warnings)
sql/item_func.cc:
c_ptr() -> c_ptr_safe()
sql/key.cc:
In key_copy() and key_restore() don't copy data for fields with NULL value
sql/opt_range.cc:
c_ptr() -> c_ptr_safe()
sql/sql_base.cc:
Added TRASH() to table->record[0] to find out if we access not initialzed data.
Initialize null_bytes to:
- Get consistent tests
- Ensure we don't get valgrind warnings for null fields (as we may only update a couple of bits in a byte)
sql/sql_class.cc:
Removed "QQ" from comments
sql/sql_insert.cc:
Initialize row to default values if we are using valgrind and row will be copied verbatim to disk in storage engine.
sql/sql_load.cc:
QQ -> TODO
sql/sql_parse.cc:
Removed old not used code marked QQ and withing "#ifdef REMOVED"
sql/sql_select.cc:
QQ -> TODO
Initialize some variables that was used uninitialized
Added DBUG_ASSERT() to find out if thd was not properly initialized for sub queries
sql/sql_test.cc:
Fixed format for printing to DBUG file
Fixed wrong alias used (from previous patch)
sql/sql_trigger.h:
QQ -> TODO
sql/table.cc:
QQ -> TODO
storage/maria/ha_maria.cc:
Mark table with HA_RECORD_MUST_BE_CLEAN_ON_WRITE, if row is written verbatim to disk and contains varchar or null fields.
storage/maria/ma_open.c:
Added flags if table has varchar or null fields
storage/maria/maria_def.h:
Added flags if table has varchar or null fields
storage/myisam/ha_myisam.cc:
Mark table with HA_RECORD_MUST_BE_CLEAN_ON_WRITE, if row is written verbatim to disk and contains varchar or null fields.
storage/myisam/mi_open.c:
Fixed memory overrun bug when using fulltext keys
storage/xtradb/row/row0sel.c:
Removed initialization of null bits. (not needed anymore)
Fix post-merge failure in 5.1-merge
- Let QUICK_RANGE_INTERSECT_SELECT not make assumption that HA_EXTRA_KEYREAD
scans do not touch parts of table->record[0] that refer to fields that are
not covered by the used index.
This assumption is not true for XtraDB (e.g. grep row/row0sel.c for
"init null bytes with default values as they might be").
- Changed TABLE->alias to String to get fewer reallocs when alias are used.
- Preallocate some buffers
Changed some String->c_ptr() -> String->ptr() when \0 is not needed.
Fixed wrong usage of String->ptr() when we need a \0 terminated string.
Use my_strtod() instead of my_atof() to avoid having to add \0 to string.
c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
zr
sql/event_db_repository.cc:
Update usage of TABLE->alias
sql/event_scheduler.cc:
c_ptr() -> c_ptr_safe()
sql/events.cc:
c_ptr() -> ptr() as \0 was not needed
sql/field.cc:
Update usage of TABLE->alias
sql/field.h:
Update usage of TABLE->alias
sql/ha_partition.cc:
Update usage of TABLE->alias
sql/handler.cc:
Update usage of TABLE->alias
Fixed wrong usage of str.ptr()
sql/item.cc:
Fixed error where code wrongly assumed string was \0 terminated.
sql/item_func.cc:
c_ptr() -> c_ptr_safe()
Update usage of TABLE->alias
sql/item_sum.h:
Use my_strtod() instead of my_atof() to avoid having to add \0 to string
sql/lock.cc:
Update usage of TABLE->alias
sql/log.cc:
c_ptr() -> ptr() as \0 was not needed
sql/log_event.cc:
c_ptr_quick() -> ptr() as \0 was not needed
sql/opt_range.cc:
ptr() -> c_ptr() as \0 is needed
sql/opt_subselect.cc:
Update usage of TABLE->alias
sql/opt_table_elimination.cc:
Update usage of TABLE->alias
sql/set_var.cc:
ptr() -> c_ptr() as \0 is needed
c_ptr() -> c_ptr_safe()
sql/sp.cc:
c_ptr() -> ptr() as \0 was not needed
sql/sp_rcontext.cc:
Update usage of TABLE->alias
sql/sql_base.cc:
Preallocate buffers
Update usage of TABLE->alias
sql/sql_class.cc:
Fix arguments to sprintf() to work even if string is not \0 terminated
sql/sql_insert.cc:
Update usage of TABLE->alias
c_ptr() -> ptr() as \0 was not needed
sql/sql_load.cc:
Preallocate buffers
Trivial optimizations
sql/sql_parse.cc:
Trivial optimization
sql/sql_plugin.cc:
c_ptr() -> ptr() as \0 was not needed
sql/sql_select.cc:
Update usage of TABLE->alias
sql/sql_show.cc:
Update usage of TABLE->alias
sql/sql_string.h:
Added move() function to move allocated memory from one object to another.
sql/sql_table.cc:
Update usage of TABLE->alias
c_ptr() -> c_ptr_safe()
sql/sql_test.cc:
ptr() -> c_ptr_safe()
sql/sql_trigger.cc:
Update usage of TABLE->alias
c_ptr() -> c_ptr_safe()
sql/sql_update.cc:
Update usage of TABLE->alias
sql/sql_view.cc:
ptr() -> c_ptr_safe()
sql/sql_yacc.yy:
ptr() -> c_ptr()
sql/table.cc:
Update usage of TABLE->alias
sql/table.h:
Changed TABLE->alias to String to get fewer reallocs when alias are used.
storage/federatedx/ha_federatedx.cc:
Use c_ptr_safe() to ensure strings are \0 terminated.
storage/maria/ha_maria.cc:
Update usage of TABLE->alias
storage/myisam/ha_myisam.cc:
Update usage of TABLE->alias
storage/xtradb/row/row0sel.c:
Ensure that null bits in record are properly reset.
(Old code didn't work as row_search_for_mysql() can be called twice while reading fields from one row.
Regression introduced by WL#2649.
Problem: queries with date/datetime columns did not use indexes:
set names non_latin1_charset;
select * from date_index_test
where date_column between '2010-09-01' and '2010-10-01';
before WL#2649 indexes worked fine because charset of
date/datetime
columns was BINARY which always won.
Fix: testing that collation of the operation matches collation
of the field is only needed in case of "real" string data types.
For DATE, DATETIME it's not needed.
@ mysql-test/include/ctype_numconv.inc
@ mysql-test/r/ctype_binary.result
@ mysql-test/r/ctype_cp1251.result
@ mysql-test/r/ctype_latin1.result
@ mysql-test/r/ctype_ucs.result
@ mysql-test/r/ctype_utf8.result
Adding tests
@ sql/field.h
Adding new method Field_str::match_collation_to_optimize_range()
for use in opt_range.cc to distinguish between
"real string" types like CHAR, VARCHAR, TEXT
(Field_string, Field_varstring, Field_blob)
and "almost string" types DATE, TIME, DATETIME
(Field_newdate, Field_datetime, Field_time, Field_timestamp)
@ sql/opt_range.cc
Using new method instead of checking result_type() against STRING result.
Note:
Another part of this problem (which is not regression)
is submitted separately (see bug##58329).
BUG#26447 prefer a clustered key for an index scan, as secondary index is always slower
... which was fixed to cause
BUG#35850 queries take 50% longer
... and was reverted
and
BUG#39653 prefer a secondary index for an index scan, as clustered key is always slower
... which was fixed to cause
BUG#55656 mysqldump takes six days instead of half an hour
... and was amended with a special case workaround
sql/opt_range.cc:
move get_index_only_read_time() into the handler class
sql/sql_select.cc:
use cost not an index length when choosing a cheaper index
