Set the lock wait timeout to 1 beforehand, and reset it afterwards, to
avoid lock conflict caused by opening the same table twice in case of
self-reference.
The function spider_db_mbase::print_warnings() can potentially result
in a null pointer dereference.
Remove the null pointer dereference by cleaning up the function.
Some small changes to the original commit
422fb63a9b.
Co-Authored-By: Yuchen Pei <yuchen.pei@mariadb.com>
Spider converts HA_READ_KEY_EXACT to the equality (=) in the
function spider_db_append_key_where_internal() but the conversion
is not necessarily correct for tables with prefix indices.
We fix the bug by converting HA_READ_KEY_EXACT to 'LIKE "foo%"' when
a target key is a prefix key. The fix is partly inspired by FEDERATED.
See ha_federated::create_where_from_key() for more details.
Delete the deprecated variable, spider_use_handler and related code.
Spider now does not supports accessing data nodes via handler
statements. Thus, the notion of SQL kinds are no longer useful.
We too discard it.
Remove the dead-code, in Spider, which is related to the Spider's
HandlerSocket support. The code has been disabled for a long time
and it is unlikely that the code will be enabled.
Prototype change:
- virtual ha_rows records_in_range(uint inx, key_range *min_key,
- key_range *max_key)
+ virtual ha_rows records_in_range(uint inx, const key_range *min_key,
+ const key_range *max_key,
+ page_range *res)
The handler can ignore the page_range parameter. In the case the handler
updates the parameter, the optimizer can deduce the following:
- If previous range's last key is on the same block as next range's first
key
- If the current key range is in one block
- We can also assume that the first and last block read are cached!
This can be used for a better calculation of IO seeks when we
estimate the cost of a range index scan.
The parameter is fully implemented for MyISAM, Aria and InnoDB.
A separate patch will update handler::multi_range_read_info_const() to
take the benefits of this change and also remove the double
records_in_range() calls that are not anymore needed.
Add the following parameter.
- spider_sync_sql_mode
Local sql_mode synchronous existence to remote server.
0 : It doesn't synchronize.
1 : It synchronizes.
The default value is 1
Add the following parameters.
- spider_remote_wait_timeout
Set remote wait_timeout at connecting for improvement performance of
connection if you know.
-1,0 : No set.
1 or more : Seconds.
The default value is -1
- spider_wait_timeout
The wait time to remote servers.
-1,0 : No set.
1 or more : Seconds.
The default value is 604800
