Hi, Sergei! On Mon, Dec 6, 2021 at 11:22 PM Sergei Golubchik <serg@mariadb.org> wrote:
Hi, Aleksey!
On Dec 05, Aleksey Midenkov wrote:
diff --git a/sql/sql_base.cc b/sql/sql_base.cc index ac22a63bdba..459edb614f7 100644 --- a/sql/sql_base.cc +++ b/sql/sql_base.cc @@ -4203,6 +4444,15 @@ bool open_tables(THD *thd, const DDL_options_st &options, }
thd->current_tablenr= 0; + +#ifdef WITH_PARTITION_STORAGE_ENGINE + if (!thd->stmt_arena->is_conventional()) + { + for (tables= *start; tables; tables= tables->next_global) + tables->vers_skip_create= false; + }
This looks a bit like an overkill, you do it for every prepare, while auto-adding a partition is a rare event, as you said.
May be you can do instead in TABLE::vers_switch_partition
uint *create_count= !thd->stmt_arena->is_conventional() && table_list->vers_skip_create ?
No, this is inside backoff action loop. That will interfere with the normal vers_skip_create algorithm (which also applies to PS, SP). The goal of the above code is to reset vers_skip_create from the previous statement execution.
In that case you can use an auto-resetting value, like, if tables->vers_skip_create == thd->query_id it means, "skip". That is vers_skip_create must be of query_id_t. You set it with tables->vers_skip_create= thd->query_id; And on the next statement it automatically expires.
This semantics is a bit more complex than boolean, so it'd need a comment, like
/* Protect single thread from repeating partition auto-create over multiple share instances (as the share is closed on backoff action). Skips auto-create only for one given query id. */ query_id_t vers_skip_create;
Done! Thanks for the tip.
Regards, Sergei VP of MariaDB Server Engineering and security@mariadb.org
-- @midenok