The function collect_statistics_for_table() when scanning a table
did not take into account that the handler function ha_rnd_next
could return the code HA_ERR_RECORD_DELETE that should not be
considered as an indication of an error.
Also fixed a potential memory leak in this function.
With the new code of mysql-5.5 for metadata locking the function
unlock_tables_n_open_system_tables_for_write should not explicitly
unlock tables for which external locks have been set and should not
explicitly reset thd->lock to 0.
- Moved the definitions of the classes to store data from persistent
statistical tables into statistics.h, leaving in other internal
data structures only references to the corresponding objects.
- Defined class Column_statistics_collected derived from the class
Column_statistics. This is a helper class to collect statistics
on columns.
- Moved references to read statistics to TABLE SHARE, leaving the
the reference to the collected statistics in TABLE.
- Added a new clone method for the class Field allowing to clone
fields attached to table shares. It was was used to create
fields for min/max values in the memory of the table share.
A lso:
- Added procedures to allocate memory for statistical data in
the table share memory and in table memory.
Also:
- Added a test case demonstrating how ANALYZE could work in parallel
to collect statistics on different indexes of the same table.
- Added a test two demonstrate how two connections working
simultaneously could allocate memory for statistical data in the
table share memory.
Renamed the system variable optimizer_use_stat_tables to use_stat_tables.
This variable now has only 3 possible values:
'never', 'complementary', 'preferably'.
If the server has been launched with
--use-stat-tables='complementary'|'preferably'
then the statictics tables can be employed by the optimizer and by the
ANALYZE command.
