Re: [PATCH] add relation and block-level filtering to pg_waldump

On Fri, 25 Mar 2022 at 08:55, Thomas Munro <thomas.munro@gmail.com> wrote:
> On Fri, Mar 25, 2022 at 1:43 PM Japin Li <japinli@hotmail.com> wrote:
>> +       printf(_("  -x, --xid=XID          only show records with transaction ID XID\n"));
>>
>> I think the description of transaction ID is enough, IIUC, XID is use in core,
>> which means transaction ID.
>
> The mention of "XID" corresponds to XID on the left, like a sort of
> variable.  That text is not changed by this patch.
>
>> See: src/bin/pg_resetwal/pg_resetwal.c
>>
>> 1239     printf(_("  -V, --version                    output version information, then exit\n"));
>> 1240     printf(_("  -x, --next-transaction-id=XID    set next transaction ID\n"));
>
> Hmm, yeah that is inconsistent, but it seems like it is pg_resetwal.c
> that is not following the notational convention there.  Other things
> in pg_resetwal's --help use that 'variable' style.
>

Thanks for your explanation!

>> +                               if (sscanf(optarg, "%u/%u/%u",
>> +                                                  &config.filter_by_relation.spcNode,
>> +                                                  &config.filter_by_relation.dbNode,
>> +                                                  &config.filter_by_relation.relNode) != 3 ||
>> +                                       !OidIsValid(config.filter_by_relation.spcNode) ||
>> +                                       !OidIsValid(config.filter_by_relation.relNode))
>>
>> It seems we should also check the dbNode.
>
> This was discussed earlier: it's OK for the dbNode to be invalid (0),
> because that's how shared relations like pg_database are referenced.
> Like this:
>
> $ pg_waldump pgdata/pg_wal/000000010000000000000001 --relation
> 1664/0/1262 --fork vm --limit 1
> rmgr: Heap2       len (rec/tot):     64/  8256, tx:          0, lsn:
> 0/01491F20, prev 0/01491EC0, desc: VISIBLE cutoff xid 1 flags 0x03,
> blkref #0: rel 1664/0/1262 fork vm blk 0 FPW, blkref #1: rel
> 1664/0/1262 blk 0
>

Oh, my bad, I missed the discussion email.  Sorry for the noise.


--
Regrads,
Japin Li.
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