VTMD: configure prelocking for ..as of.. stmt #1
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Problem: When nested queries are used inside `as of` statement, needed tables are locked before execution, but whole thread tables are unlocked after it. So, we unlock tables that shouldn't be unlocked. This affects `select` and `show create table` queries. Solution: Nested locking is forbidden. Instead, all tables are to be opened at once. So we add all vtmd tables to lexer's table list and then open them in a row with other tables used in query.
rename prepare_for_read -> add_to_prelocking_list remove junk comment
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The code is fine. Additionally you can make sure that |
Prelocking is only enabled when stored routines or nested queries are used
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Problem:
When nested queries are used inside
as ofstatement, needed tablesare locked before execution, but whole thread tables are unlocked after
it. So, we unlock tables that shouldn't be unlocked. This affects
selectand
show create tablequeries.Solution:
Nested locking is forbidden. Instead, all tables are to be opened at
once. So we add all vtmd tables to lexer's table list and then open
them in a row with other tables used in query.