Re: Perform streaming logical transactions by background workers and parallel apply
Amit Kapila <amit.kapila16@gmail.com>
On Wed, Dec 21, 2022 at 11:02 AM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
>
> Attach the new patch set which also includes some
> cosmetic comment changes.
>
I noticed one problem with the recent change in the patch.
+ * The fileset state should become FS_SERIALIZE_DONE once we have waited
+ * for a lock in the FS_SERIALIZE_IN_PROGRESS state, so we get the state
+ * again and recheck it later.
+ */
+ if (fileset_state == FS_SERIALIZE_IN_PROGRESS)
+ {
+ pa_lock_stream(MyParallelShared->xid, AccessShareLock);
+ pa_unlock_stream(MyParallelShared->xid, AccessShareLock);
+
+ fileset_state = pa_get_fileset_state();
+ Assert(fileset_state == FS_SERIALIZE_DONE);
This is not always true because say due to deadlock, this lock is
released by the leader worker, in that case, the file state will be
still in progress. So, I think we need a change like the below:
diff --git a/src/backend/replication/logical/applyparallelworker.c
b/src/backend/replication/logical/applyparallelworker.c
index 45faa74596..8076786f0d 100644
--- a/src/backend/replication/logical/applyparallelworker.c
+++ b/src/backend/replication/logical/applyparallelworker.c
@@ -686,8 +686,8 @@ pa_spooled_messages(void)
* the leader had serialized all changes which can lead to undetected
* deadlock.
*
- * The fileset state must be FS_SERIALIZE_DONE once the leader
worker has
- * finished serializing the changes.
+ * Note that the fileset state can be FS_SERIALIZE_DONE once the leader
+ * worker has finished serializing the changes.
*/
if (fileset_state == FS_SERIALIZE_IN_PROGRESS)
{
@@ -695,7 +695,6 @@ pa_spooled_messages(void)
pa_unlock_stream(MyParallelShared->xid, AccessShareLock);
fileset_state = pa_get_fileset_state();
- Assert(fileset_state == FS_SERIALIZE_DONE);
--
With Regards,
Amit Kapila.
Commits
GET /api/v1/messages/:b64id/commits
the thread's linked commits as JSON, with link sources.
API reference →
-
Fix invalid memory access during the shutdown of the parallel apply worker.
- 3d144c6c8602 16.0 landed
-
Fix assertion failure in apply worker.
- de63f8dadee4 16.0 landed
-
Use elog to report unexpected action in handle_streamed_transaction().
- 781ac42d43ab 16.0 landed
-
Use appropriate wait event when sending data in the apply worker.
- d9d7fe68d35e 16.0 landed
-
Allow the logical_replication_mode to be used on the subscriber.
- 9f2213a7c575 16.0 landed
-
Rename GUC logical_decoding_mode to logical_replication_mode.
- 1e8b61735cfb 16.0 landed
-
Display the leader apply worker's PID for parallel apply workers.
- d540a02a724b 16.0 landed
-
Improve the code to decide and process the apply action.
- c981d9145dea 16.0 landed
-
Document the newly added wait events added by commit 216a784829.
- cd06ccd78fcf 16.0 landed
-
Perform apply of large transactions by parallel workers.
- 216a784829c2 16.0 landed
-
Wake up a subscription's replication worker processes after DDL.
- c6e1f62e2cee 16.0 cited
-
Add copyright notices to meson files
- 8284cf5f746f 16.0 cited
-
Better document logical replication parameters
- a8500750ca0a 16.0 cited
-
Add a common function to generate the origin name.
- 776e1c8a5d14 16.0 cited
-
Harmonize parameter names in storage and AM code.
- bfcf1b34805f 16.0 cited
-
Avoid using list_length() to test for empty list.
- efd0c16becbf 16.0 cited
-
Improve two comments related to a boolean DefElem's value
- 8445f5a21d40 16.0 cited
-
Fix partition table's REPLICA IDENTITY checking on the subscriber.
- 26b3455afaa9 15.0 cited
-
Fix data inconsistency between publisher and subscriber.
- b7658c24c7c1 15.0 cited
-
Fix cache look-up failures while applying changes in logical replication.
- 5a97b1325453 15.0 cited