On Tue, Oct 01, 2019 at 06:55:52PM +0530, Amit Kapila wrote: > >On further testing, I found that the patch seems to have problems with >toast. Consider below scenario: >Session-1 >Create table large_text(t1 text); >INSERT INTO large_text >SELECT (SELECT string_agg('x', ',') >FROM generate_series(1, 1000000)) FROM generate_series(1, 1000); > >Session-2 >SELECT * FROM pg_create_logical_replication_slot('regression_slot', >'test_decoding'); >SELECT * FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL); >*--kaboom* > >The second statement in Session-2 leads to a crash. >
OK, thanks for the report - will investigate.
It was an assertion failure in ReorderBufferCleanupTXN at below line:
+ /* Check we're not mixing changes from different transactions. */ + Assert(change->txn == txn);
>Other than that, I am not sure if the changes related to spill to disk >after logical_decoding_work_mem works for toast table as I couldn't hit >that code for toast table case, but I might be missing something. As >mentioned previously, I feel there should be some way to test whether this >patch works for the cases it claims to work. As of now, I have to check >via debugging. Let me know if there is any way, I can test this. >
That's one of the reasons why I proposed to move the statistics (which say how many transactions / bytes were spilled to disk) from a later patch in the series. I don't think there's a better way.
I like that idea, but I think you need to split that patch to only get the stats related to the spill. It would be easier to review if you can prepare that atop of 0001-Add-logical_decoding_work_mem-to-limit-ReorderBuffer.
