Treat queries with no FROM and aggregate functions as normal queries,
so the aggregate function get correctly calculated as if there is 1 row.
This means that they will be considered to have one row, so COUNT(*) will return
1 instead of 0. Other aggregates will behave in compatible manner.
functions in queries
Using MAX()/MIN() on table with disabled indexes (by ALTER TABLE)
results in error 124 (wrong index) from storage engine.
The problem was that optimizer use disabled index to optimize
MAX()/MIN(). Normally it must skip disabled index and perform
table scan.
This patch skips disabled indexes for min/max optimization.
The bug report revealed two problems related to min/max optimization:
1. If the length of a constant key used in a SARGable condition for
for the MIN/MAX fields is greater than the length of the field an
unwanted warning on key truncation is issued;
2. If MIN/MAX optimization is applied to a partial index, like INDEX(b(4))
than can lead to returning a wrong result set.
The problem was in that the MIN/MAX optimization in opt_sum_query was
replacing MIN/MAX functions with their constant argument without
taking into account that a query has no result rows.
Logging to logging@openlogging.org accepted
func_group.result, func_group.test:
Added a test case for bug #8893.
opt_sum.cc:
A misplaced initialization for the returned parameter
prefix_len in the function find_key_for_maxmin caused
usage of a wrong key prefix by the min/max optimization
in cases when the matching index was not the first index
that contained the min/max field.
more logical table/index_flags
return HA_ERR_WRONG_COMMAND instead of abstract methods where appropriate
max_keys and other limits renamed to max_supported_keys/etc
max_keys/etc are now wrappers to max_supported_keys/etc
ha_index_init/ha_rnd_init/ha_index_end/ha_rnd_end are now wrappers to real {index,rnd}_{init,end} to enforce strict pairing
New records_in_range() interface (similar to read_range())
Macros for faster bitmap handling
Simplify read_range() code (#WL1786)
New general key_cmp() function to compare keys
Added new tests for better coverage of
min/max optimization code.
func_group.test:
Added new tests for better coverage of
min/max optimization code.
opt_sum.cc:
Fixed wrong previous manual merge.
Fixed bugs concerning fields used in min/max
functions for which there are conditions of
the form field=const.
MIN(key_column) could in some cases return NULL on a column with NULL and other values.
MIN(key_column) and MAX(key_column) could in some cases return wrong values when used in OUTER JOIN.
Some simple optimzations, more comments and indentation changes.
Add ` around database in 'use database' in binary log.
Moved max_error_count and max_warning_count to variables struct.
Removed SHOW_WARNS_COUNT and SHOW_ERRORS_COUNT calls.
Changed string functions to use character set of first string argument as default return characterset
(Each string function can change the above assumption if needed)
This one is better, but should not be final.
Better fix is to make some changes in ha_myisammrg::index_read
This patch also reverts my previous one ...
fixed apparent typo in opt_sum.cc
I will push this Changeset although it fails select test - failing select
is better than the code that does not compile.
Bug fix when using --no-deaults
Sets ref_length to right value (faster rnd_pos() handling in InnoDB).
Fixed problem with multi-table-delete and InnoDB
Fixed problem with truncate table, which required a COMMIT before.
Fixed multi-table-delete bug with InnoDB.
Remove not used index from EXPLAIN
New faster list iterators
Change list code to be simpler and faster
Optimize count(distinct)
New error messages for UNION
Make create_tmp_table more general to be usable by UNION
