Made allocation of memory for statistical data in a table share to be thread safe.
This memory is now allocated in a special MEM_ROOT that is created for each
table share.
that introduced engine independent persistent statistics.
In particular:
- added an enumeration type for possible values of the system
variable use_stat_tables
- renamed KEY::real_rec_per_key to KEY::actual_rec_per_key
- optimized the collection of statistical data for any primary
key defined only on one column.
If a query referenced some system statistical tables, but not all of them,
then executing an ANALYZE command simultaneously with this query could
lead to a deadlock.
The fix prohibited reading statistics from system statistical tables
for such queries.
Removed the function unlock_tables_n_open_system_tables_for_write()
as not used anymore.
Performed some minor refactoring of the code in sql_statistics.cc.
engine-independent statistics.
If a table was created for InnoDB then the execution of the
ANALYZE command over this table blocked any INSERT/DELETE/UPDATE
of the table.
engine-independent statistics.
When the primary key was dropped or changed statistics on secondary
indexes for the prefixes that included components of the primary
key was not removed from the table mysql.index_stats.
Also fixed: in the some cases when a column was changed statistics
on the indexes that included this column was not removed from the
table mysql.index_stats.
Also disabled the test mdev-504 for --ps-protocol.
table_stat -> table_stats
column_stat -> column_stats
index_stat -> index_stats
to be in line with the names of innodb statistical tables
from mysql-5.6: innodb_table_stats and innodb_index_stats.
RBR should be turned off when statistical tables are modified
in the result of the execution of a DDL statement.
Revised the fix for bug mdev-463. Ensured suppression of RBR
for the modifications of the statistical tables triggered
by the execution of any analyze operation.
Any Field object should use current_thd instead of table->in_use
when THD is needed if table == NULL.
This patch fixes the crash of test case from mdev-504.test.
Opening system statistical tables and reading statistical data from
them for a regular table should be done after opening and locking
this regular table.
No test case is provided with this patch.
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.
- 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.
Now when a table is dropped the statistics on the table is removed
from the statistical tables. If the table is altered in such a way
that a column is dropped or the type of the column is changed then
statistics on the column is removed from the table column_stat.
It also triggers removal of the statistics on the indexes who use
this column as its component.
Added procedures that changes the names of the tables or columns
in the statistical tables for.
These procedures are used when tables/columns are renamed.
Also partly re-factored the code that introduced the persistent
statistical tables.
Added test cases into statistics.test to cover the new code.
mysql.column_stat, mysql.table_stat for the type DECIMAL(12,4).
When cached the values from these columns are multiplied by factor 10^5
and stored as ulong numbers now.
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.
the server crashed when running the query with persistent statistics
enabled.
The field KEY::read_stat.avg_frequency must be initialized to NULL
for the keys of temporary tables.
