When setting the server lockwait timeout, spider should do some basic
checks first, like whether the remote server is still reachable. So
instead of directly calling spider_db_mbase::exec_query(), it should
call spider_db_query().
The reset of the lock wait timeout does not need to do such checks,
because they happen after the successfully setting the lock wait
timeout, implying the checks have been passed already.
spider_db_mbase_util::open_item_func() is a monster function.
It is difficult to maintain while it is expected that we need to
modify it when a new SQL function or a new func_type is added.
We split the function into two distinct functions: one handles the
case of str != NULL and the other handles the case of str == NULL.
This refactoring was done in a conservative way because we do not
have comprehensive tests on the function.
It also fixes MDEV-29447 and MDEV-31338 where field items that are
arguments of a func item may be used before created / initialised.
Note this commit is adapted from a patch by Nayuta for MDEV-26285.
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.
Extracted out common subroutines, gave more meaningful names etc,
added comments etc.
Also:
- Documented active servers load balancing reads, and other fields in
SPIDER_SHARE etc.
- Removed commented out code
- Documented and refactored self-reference check
- Removed some unnecessary functions
- Renamed unhelpful roop_count
- Refactored spider_get_{sts,crd}, where we turn get_type into an enum
- Cleaned up spider_mbase_handler::show_table_status() and
spider_mbase_handler::show_index()
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>
The conn_kind, which stands for "connection kind", is no longer useful
because the HandlerSocket support is deleted and Spider now has only
one connection kind, SPIDER_CONN_KIND_MYSQL. Remove conn_kind and
related code.
Signed-off-by: Yuchen Pei <yuchen.pei@mariadb.com>
Reviewed-by: Nayuta Yanagisawa <nayuta.yanagisawa@mariadb.com>
