diff options
| author | Alexander Korotkov <akorotkov@postgresql.org> | 2023-03-23 00:13:37 +0300 |
|---|---|---|
| committer | Alexander Korotkov <akorotkov@postgresql.org> | 2023-03-23 00:26:59 +0300 |
| commit | 11470f544e3729c60fab890145b2e839cbc8905e (patch) | |
| tree | 8ebd3c5b4aab9023e54e71e892b91a5beb9de8dc /src/tools | |
| parent | 764da7710bf68eebb2c0facb2f871bc3c7a705b6 (diff) | |
| download | postgresql-11470f544e3729c60fab890145b2e839cbc8905e.tar.gz | |
Allow locking updated tuples in tuple_update() and tuple_delete()
Currently, in read committed transaction isolation mode (default), we have the
following sequence of actions when tuple_update()/tuple_delete() finds
the tuple updated by concurrent transaction.
1. Attempt to update/delete tuple with tuple_update()/tuple_delete(), which
returns TM_Updated.
2. Lock tuple with tuple_lock().
3. Re-evaluate plan qual (recheck if we still need to update/delete and
calculate the new tuple for update).
4. Second attempt to update/delete tuple with tuple_update()/tuple_delete().
This attempt should be successful, since the tuple was previously locked.
This patch eliminates step 2 by taking the lock during first
tuple_update()/tuple_delete() call. Heap table access method saves some
efforts by checking the updated tuple once instead of twice. Future
undo-based table access methods, which will start from the latest row version,
can immediately place a lock there.
The code in nodeModifyTable.c is simplified by removing the nested switch/case.
Discussion: https://postgr.es/m/CAPpHfdua-YFw3XTprfutzGp28xXLigFtzNbuFY8yPhqeq6X5kg%40mail.gmail.com
Reviewed-by: Aleksander Alekseev, Pavel Borisov, Vignesh C, Mason Sharp
Reviewed-by: Andres Freund, Chris Travers
Diffstat (limited to 'src/tools')
| -rw-r--r-- | src/tools/pgindent/typedefs.list | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 097f42e1b3..0b7bc45767 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -955,6 +955,7 @@ GenerationPointer GenericCosts GenericXLogState GeqoPrivateData +GetEPQSlotArg GetForeignJoinPaths_function GetForeignModifyBatchSize_function GetForeignPaths_function @@ -1399,6 +1400,7 @@ LagTracker LargeObjectDesc LastAttnumInfo Latch +LazyTupleTableSlot LerpFunc LexDescr LexemeEntry |