postgres

Commit Graph

Author	SHA1	Message	Date
Tom Lane	0adaf4cb31	Move the handling of SELECT FOR UPDATE locking and rechecking out of execMain.c and into a new plan node type LockRows. Like the recent change to put table updating into a ModifyTable plan node, this increases planning flexibility by allowing the operations to occur below the top level of the plan tree. It's necessary in any case to restore the previous behavior of having FOR UPDATE locking occur before ModifyTable does. This partially refactors EvalPlanQual to allow multiple rows-under-test to be inserted into the EPQ machinery before starting an EPQ test query. That isn't sufficient to fix EPQ's general bogosity in the face of plans that return multiple rows per test row, though. Since this patch is mostly about getting some plan node infrastructure in place and not about fixing ten-year-old bugs, I will leave EPQ improvements for another day. Another behavioral change that we could now think about is doing FOR UPDATE before LIMIT, but that too seems like it should be treated as a followon patch.	17 years ago

Author

SHA1

Message

Date

Tom Lane

0adaf4cb31

Move the handling of SELECT FOR UPDATE locking and rechecking out of

execMain.c and into a new plan node type LockRows.  Like the recent change
to put table updating into a ModifyTable plan node, this increases planning
flexibility by allowing the operations to occur below the top level of the
plan tree.  It's necessary in any case to restore the previous behavior of
having FOR UPDATE locking occur before ModifyTable does.

This partially refactors EvalPlanQual to allow multiple rows-under-test
to be inserted into the EPQ machinery before starting an EPQ test query.
That isn't sufficient to fix EPQ's general bogosity in the face of plans
that return multiple rows per test row, though.  Since this patch is
mostly about getting some plan node infrastructure in place and not about
fixing ten-year-old bugs, I will leave EPQ improvements for another day.

Another behavioral change that we could now think about is doing FOR UPDATE
before LIMIT, but that too seems like it should be treated as a followon
patch.

17 years ago

1 Commits (8292079ad3db05faff01d03c7a8646704edbf54b)