Horton

Re: libpq debug log

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "'alvherre@alvh.no-ip.org'" <alvherre@alvh.no-ip.org>
Cc: "iwata.aya@fujitsu.com" <iwata.aya@fujitsu.com>, "tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>, "k.jamison@fujitsu.com" <k.jamison@fujitsu.com>, "'Kyotaro Horiguchi'" <horikyota.ntt@gmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2021-03-10T20:03:35Z
Lists: pgsql-hackers 
"'alvherre@alvh.no-ip.org'" <alvherre@alvh.no-ip.org> writes:
> After staring at it a couple of times, I think that the places in
> pqParseInput3() where there's a comment "... moves inStart itself" and
> then "continue;" should have a call to pqTraceOutputMsg(), since AFAIU
> those are the places where the message in question would not reach the
> "Successfully consumed this message" block that prints each message.

Yeah, the whole business of just when a message has been "consumed"
is a stumbling block for libpq tracing.  It was a real mess with the
existing code and v2 protocol, because we could actually try to parse
a message more than once, with the first few tries deciding that the
message wasn't all here yet (but nonetheless emitting partial trace
output).

Now that v2 is dead, the logic to abort because of the message not
being all arrived yet is basically useless: only the little bit of
code concerned with the message length word really needs to cope with
that.  It's tempting to go through and get rid of all the now-unreachable
"return"s and such, but it seemed like it would be a lot of code churn for
not really that much gain.

I didn't look at the new version of the patch yet, so I'm not
sure whether the issues it still has are related to this.

			regards, tom lane

Commits

  1. Rename PQtraceSetFlags() to PQsetTraceFlags().

  2. Suppress length of Notice/Error msgs in PQtrace regress mode

  3. Strip file names reported in error messages on Windows, too.

  4. Fix setvbuf()-induced crash in libpq_pipeline

  5. libpq_pipeline: Must strdup(optarg) to avoid crash

  6. Remove setvbuf() call from PQtrace()

  7. Initialize conn->Pfdebug to NULL when creating a connection

  8. Disable force_parallel_mode in libpq_pipeline

  9. libpq_pipeline: add PQtrace() support and tests

  10. Improve PQtrace() output format

  11. Re-simplify management of inStart in pqParseInput3's subroutines.