MDEV-5980: EITS: if condition is used for REF access, its selectivity is still in filtered%
MDEV-5985: EITS: selectivity estimates look illogical for join and non-key equalities
MDEV-6003: EITS: ref access, keypart2=const vs keypart2=expr - inconsistent filtered% value
- Made a number of fixes in table_cond_selectivity() so that it returns
correct selectivity estimates.
- Added comments in related code.
Better comments
MDEV-5985: EITS: selectivity estimates look illogical for join and non-key equalities
MDEV-6003: EITS: ref access, keypart2=const vs keypart2=expr - inconsistent filtered% value
- Made a number of fixes in table_cond_selectivity() so that it returns
correct selectivity estimates.
- Added comments in related code.
Back-ported from the mysql 5.6 code line the patch with
the following comment:
Fix for Bug#11757108 CHANGE IN EXECUTION PLAN FOR COUNT_DISTINCT_GROUP_ON_KEY
CAUSES PEFORMANCE REGRESSION
The cause for the performance regression is that the access strategy for the
GROUP BY query is changed form using "index scan" in mysql-5.1 to use "loose
index scan" in mysql-5.5. The index used for group by is unique and thus each
"loose scan" group will only contain one record. Since loose scan needs to
re-position on each "loose scan" group this query will do a re-position for
each index entry. Compared to just reading the next index entry as a normal
index scan does, the use of loose scan for this query becomes more expensive.
The cause for selecting to use loose scan for this query is that in the current
code when the size of the "loose scan" group is one, the formula for
calculating the cost estimates becomes almost identical to the cost of using
normal index scan. Differences in use of integer versus floating point arithmetic
can cause one or the other access strategy to be selected.
The main issue with the formula for estimating the cost of using loose scan is
that it does not take into account that it is more costly to do a re-position
for each "loose scan" group compared to just reading the next index entry.
Both index scan and loose scan estimates the cpu cost as:
"number of entries needed too read/scan" * ROW_EVALUATE_COST
The results from testing with the query in this bug indicates that the real
cost for doing re-position four to eight times higher than just reading the
next index entry. Thus, the cpu cost estimate for loose scan should be increased.
To account for the extra work to re-position in the index we increase the
cost for loose index scan to include the cost of navigating the index.
This is modelled as a function of the height of the b-tree:
navigation cost= ceil(log(records in table)/log(indexes per block))
* ROWID_COMPARE_COST;
This will avoid loose index scan being used for indexes where the "loose scan"
group contains very few index entries.
MDEV-5984: EITS: Incorrect filtered% value for single-table select with range access
- Fix calculate_cond_selectivity_for_table() to work correctly with range accesses
over multi-component keys:
= First, take selectivity of all possible range scans into account. Remember which
fields were used bt the range scans.
= Then, calculate selectivity produced by sargable predicates on fields. If a
field was used in a possible range access, assume its selectivity is already
taken into account.
- Fix table_cond_selectivity(): when quick select is used, selectivity of
COND(table) is taken into account in matching_candidates_in_table(). In
table_cond_selectivity() we should not apply it for the second time.
After constant table row substitution the where condition may be converted
to always true. The function calculate_cond_selectivity_for_table() should
take into account this possibility.
This is port of fix for MySQL BUG#17647863.
revno: 5572
revision-id: jon.hauglid@oracle.com-20131030232243-b0pw98oy72uka2sj
committer: Jon Olav Hauglid <jon.hauglid@oracle.com>
timestamp: Thu 2013-10-31 00:22:43 +0100
message:
Bug#17647863: MYSQL DOES NOT COMPILE ON OSX 10.9 GM
Rename test() macro to MY_TEST() to avoid conflict with libc++.
The function calculate_cond_selectivity_for_table() must consider
the case when the key range tree returned by the call of get_mm_tree()
is of the type SEL_TREE::ALWAYS.
Port to mariadb-1.0 the following fix from mysql-5.6:
Revision ID: jorgen.loland@oracle.com-20120314131055-ml54x9deueqfsff4
BUG#13701206: WHERE A>=B DOES NOT GIVE SAME EXECUTION PLAN
AS WHERE B<=A (RANGE OPTIMIZER)
that fix didn't have a public testcase, so I created one.
- Added MALLOC_LIBRARY variable to hold name of malloc library
- Back ported valgrind related fixes from jemalloc 3.4.1 to the included jemalloc 3.3.1
- Renamed bitmap_init() and bitmap_free() to my_bitmap_init() and my_bitmap_free() to avoid clash with jemalloc 3.4.1
- Use option --soname-synonyms=somalloc=NON to valgrind when using jemalloc
- Show version related variables in mysqld --help
-- Added SHOW_VALUE_IN_HELP marker
Increased back_log to 150 as the original value was a bit too small
CMakeLists.txt:
Added MALLOC_LIBRARY variable to hold name of malloc library
cmake/jemalloc.cmake:
Added MALLOC_LIBRARY variable to hold name of malloc library
config.h.cmake:
Added MALLOC_LIBRARY variable to hold name of malloc library
extra/jemalloc/ChangeLog:
Updates changelog
extra/jemalloc/include/jemalloc/internal/arena.h:
Backported valgrind fixes from jemalloc 3.4.1
extra/jemalloc/include/jemalloc/internal/jemalloc_internal.h.in:
Backported valgrind fixes from jemalloc 3.4.1
extra/jemalloc/include/jemalloc/internal/private_namespace.h:
Backported valgrind fixes from jemalloc 3.4.1
extra/jemalloc/include/jemalloc/internal/tcache.h:
Backported valgrind fixes from jemalloc 3.4.1
extra/jemalloc/src/arena.c:
Backported valgrind fixes from jemalloc 3.4.1
include/my_bitmap.h:
Renamed bitmap_init() and bitmap_free() to my_bitmap_init() and my_bitmap_free() to avoid clash with jemalloc 3.4.1
mysql-test/mysql-test-run.pl:
Use option --soname-synonyms=somalloc=NON to valgrind when using jemalloc
mysql-test/valgrind.supp:
Supression of memory leak in OpenSuse 12.3
mysys/my_bitmap.c:
Renamed bitmap_init() and bitmap_free() to my_bitmap_init() and my_bitmap_free()
sql/ha_ndbcluster_binlog.cc:
Renames
sql/ha_ndbcluster_cond.h:
Renames
sql/ha_partition.cc:
Renames
sql/handler.cc:
Renames
sql/item_subselect.cc:
Renames
sql/log_event.cc:
Renames
sql/log_event_old.cc:
Renames
sql/mysqld.cc:
Renames
Show version related variables in mysqld --help
sql/opt_range.cc:
Renames
sql/opt_table_elimination.cc:
Renames
sql/partition_info.cc:
Renames
sql/rpl_injector.h:
Renames
sql/set_var.h:
Renames
sql/slave.cc:
Renames
sql/sql_bitmap.h:
Renames
sql/sql_insert.cc:
Renames
sql/sql_lex.h:
Renames
sql/sql_parse.cc:
Renames
sql/sql_partition.cc:
Renames
sql/sql_select.cc:
Renames
sql/sql_show.cc:
Renames
sql/sql_update.cc:
Renames
sql/sys_vars.cc:
Show version related variables in mysqld --help
sql/sys_vars.h:
Added SHOW_VALUE_IN_HELP marker for variables that should be shown in --help
sql/table.cc:
Renames
sql/table.h:
Removed not used bitmap_init_value
storage/connect/ha_connect.cc:
Removed compiler warning
storage/maria/ma_open.c:
Renames
unittest/mysys/bitmap-t.c:
Renames
- Query plan footprint (in new terms, "EXPLAIN structure") should always keep
a copy of key_name. This is because the table might be a temporary table which
may be already freed by the time we use query plan footprint.
- Make QPF structures store data members, not strings.
This is not fully possible, because table names (and hence
key names, etc) can be deleted, and we have to store strings.
For queries like
update t1 set ... where <unique key> order by ... limit ...
we need to handle the fact that unique keys allow NULL
values, and hence can return more than one row.
sql/opt_range.cc:
When the unique key has multiple key parts,
check each key_part for nullability, rather than the first key part.
(s/key->part ==/key_tree->part ==/)
Also: revert the if() test, for better readability.
Currently the loose scan code in opt_range.cc considers all indexes as
possible for the access method. Due to inexact statistics it may happen
that a loose scan is selected over a unique index.
This is clearly wrong since a "loose scan" over a unique index will read
the same keys as a direct index scan, but the loose scan has more overhead.
This task adds a rule to skip unique indexes for loose scan.
Added forgotten partition_explicit_prune from mysql-5.6.
Backported the fix for
Bug#13559657: PARTITION SELECTION DOES NOT WORK WITH VIEWS
from mysql-5.6
includes:
* remove some remnants of "Bug#14521864: MYSQL 5.1 TO 5.5 BUGS PARTITIONING"
* introduce LOCK_share, now LOCK_ha_data is strictly for engines
* rea_create_table() always creates .par file (even in "frm-only" mode)
* fix a 5.6 bug, temp file leak on dummy ALTER TABLE
In the case of loose scan used as input for order by, end_send()
didn't detect correctly that a loose scan was used, and didn't copy
the non-aggregated fields from the temp table used for ORDER BY.
The fix uses the fact that the quick select used for sorting is
attached to JOIN::pre_sort_join_tab instead of JOIN::join_tab.
- merge_same_index_scans() may put the same SEL_ARG tree in multiple result plans.
make it call incr_refs() on the SEL_ARG trees that it does key_or() on, because
key_or(sel_arg_tree_1, sel_arg_tree_2) call may invalidate SEL_ARG trees pointed
by sel_arg_tree_1 and sel_arg_tree_2.
