Re: Statistics Import and Export - Mailing list pgsql-hackers

On Mon, Mar 17, 2025 at 07:24:46PM -0400, Corey Huinker wrote:
> On Mon, Mar 17, 2025 at 10:24 AM Nathan Bossart <nathandbossart@gmail.com>
> wrote:
>> I'm assuming that writing a completely different TOC on the second pass
>> would corrupt the dump file.  Perhaps we could teach it to skip stats
>> entries on the second pass or something, but I'm not too wild about adding
>> to the list of invasive changes we're making last-minute for v18.
> 
> I'm confused, are they needed in both places?

AFAICT yes.  The second pass rewrites the TOC to udpate the data offset
information.  If we wrote a different TOC the second time around, then the
dump file would be broken, right?

        /*
         * If possible, re-write the TOC in order to update the data offset
         * information.  This is not essential, as pg_restore can cope in most
         * cases without it; but it can make pg_restore significantly faster
         * in some situations (especially parallel restore).
         */
        if (ctx->hasSeek &&
            fseeko(AH->FH, tpos, SEEK_SET) == 0)
            WriteToc(AH);

-- 
nathan