10 Commits (0adaf4cb312fe3eff83e786d6a0b53ae2cdc9302)

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.	16 years ago
Tom Lane	8a5849b7ff	Split the processing of INSERT/UPDATE/DELETE operations out of execMain.c. ... They are now handled by a new plan node type called ModifyTable, which is placed at the top of the plan tree. In itself this change doesn't do much, except perhaps make the handling of RETURNING lists and inherited UPDATEs a tad less klugy. But it is necessary preparation for the intended extension of allowing RETURNING queries inside WITH. Marko Tiikkaja	16 years ago
Tom Lane	d04db37072	Arrange for function default arguments to be processed properly in expressions ... that are set up for execution with ExecPrepareExpr rather than going through the full planner process. By introducing an explicit notion of "expression planning", this patch also lays a bit of groundwork for maybe someday allowing sub-selects in standalone expressions.	17 years ago
Bruce Momjian	fca9fff41b	More README src cleanups.	18 years ago
Bruce Momjian	4e228447aa	Make source code READMEs more consistent. Add CVS tags to all README files.	18 years ago
Tom Lane	bedb78d386	Implement sharable row-level locks, and use them for foreign key references ... to eliminate unnecessary deadlocks. This commit adds SELECT ... FOR SHARE paralleling SELECT ... FOR UPDATE. The implementation uses a new SLRU data structure (managed much like pg_subtrans) to represent multiple- transaction-ID sets. When more than one transaction is holding a shared lock on a particular row, we create a MultiXactId representing that set of transactions and store its ID in the row's XMAX. This scheme allows an effectively unlimited number of row locks, just as we did before, while not costing any extra overhead except when a shared lock actually has to be shared. Still TODO: use the regular lock manager to control the grant order when multiple backends are waiting for a row lock. Alvaro Herrera and Tom Lane.	21 years ago
PostgreSQL Daemon	969685ad44	$Header: -> $PostgreSQL Changes ...	22 years ago
Tom Lane	5bab36e9f6	Revise executor APIs so that all per-query state structure is built in ... a per-query memory context created by CreateExecutorState --- and destroyed by FreeExecutorState. This provides a final solution to the longstanding problem of memory leaked by various ExecEndNode calls.	23 years ago
Tom Lane	1fd0c59e25	Phase 1 of read-only-plans project: cause executor state nodes to point ... to plan nodes, not vice-versa. All executor state nodes now inherit from struct PlanState. Copying of plan trees has been simplified by not storing a list of SubPlans in Plan nodes (eliminating duplicate links). The executor still needs such a list, but it can build it during ExecutorStart since it has to scan the plan tree anyway. No initdb forced since no stored-on-disk structures changed, but you will need a full recompile because of node-numbering changes.	23 years ago
Tom Lane	7809cbf7e6	Some badly needed documentation about EvalPlanQual.	25 years ago