Re: MultiXact\SLRU buffers configuration

Le 12/03/2021 à 13:44, Andrey Borodin a écrit :
>
>> 11 марта 2021 г., в 20:50, Gilles Darold <gilles(at)darold(dot)net> написал(а):
>>
>>
>> The patch doesn't apply anymore in master cause of error: patch failed: src/backend/utils/init/globals.c:150
>>
>>
>>
>> An other remark about this patch is that it should be mentionned in the documentation (doc/src/sgml/config.sgml) that the new configuration variables need a server restart, for example by adding "This parameter can only be set at server start." like for shared_buffers. Patch on postgresql.conf mention it.
>>
>> And some typo to be fixed:
>>
>>
>>
>> s/Tipically/Typically/
>>
>> s/asincronous/asyncronous/
>>
>> s/confugured/configured/
>>
>> s/substrnsactions/substransactions/
>>
>>
> Thanks, Gilles! Fixed.
>
> Best regards, Andrey Borodin.
>

Hi Andrey,

I found two problems in this patch, first in src/include/miscadmin.h
multixact_members_slru_buffers is declared twice:

 extern PGDLLIMPORT int max_parallel_workers;
+extern PGDLLIMPORT int multixact_offsets_slru_buffers;
+extern PGDLLIMPORT int multixact_members_slru_buffers;
+extern PGDLLIMPORT int multixact_members_slru_buffers;  <---------
+extern PGDLLIMPORT int subtrans_slru_buffers;

In file src/backend/access/transam/multixact.c the second variable
should be multixact_buffers_slru_buffers and not
multixact_offsets_slru_buffers.

@@ -1848,13 +1848,13 @@ MultiXactShmemInit(void)
        MultiXactMemberCtl->PagePrecedes = MultiXactMemberPagePrecedes;

        SimpleLruInit(MultiXactOffsetCtl,
-                                 "MultiXactOffset",
NUM_MULTIXACTOFFSET_BUFFERS, 0,
+                                 "MultiXactOffset",
multixact_offsets_slru_buffers, 0,
                                  MultiXactOffsetSLRULock,
"pg_multixact/offsets",
                                  LWTRANCHE_MULTIXACTOFFSET_BUFFER,
                                  SYNC_HANDLER_MULTIXACT_OFFSET);
        SlruPagePrecedesUnitTests(MultiXactOffsetCtl,
MULTIXACT_OFFSETS_PER_PAGE);
        SimpleLruInit(MultiXactMemberCtl,
-                                 "MultiXactMember",
NUM_MULTIXACTMEMBER_BUFFERS, 0,
+                                 "MultiXactMember",
multixact_offsets_slru_buffers, 0,    <------------------
                                  MultiXactMemberSLRULock,
"pg_multixact/members",
                                  LWTRANCHE_MULTIXACTMEMBER_BUFFER,
                                  SYNC_HANDLER_MULTIXACT_MEMBER);

Please fix them so that I can end the review.

--
Gilles Darold
LzLabs GmbH
http://www.lzlabs.com/