Re: Fix comments related to pending statistics - Mailing list pgsql-hackers

From Bertrand Drouvot
Subject Re: Fix comments related to pending statistics
Date
Msg-id Z1lAFklwL3TrZfwR@ip-10-97-1-34.eu-west-3.compute.internal
Whole thread Raw
List pgsql-hackers
Hi,

On Wed, Dec 11, 2024 at 02:56:08PM +0900, Michael Paquier wrote:
> On Tue, Dec 10, 2024 at 02:16:14PM +0000, Bertrand Drouvot wrote:
> > 
> > 2. One linked to PgStat_FunctionCounts pending stats, mentioning the use of
> > memcmp() against zeroes to detect whether there are any pending stats: I think
> > it has never been the case.
> 
>   * PgStat_FunctionCounts    The actual per-function counts kept by a backend
>   *
> - * This struct should contain only actual event counters, because we memcmp
> - * it against zeroes to detect whether there are any pending stats.
> + * This struct should contain only actual event counters, because pending stats
> + * always has non-zero content.
> 
> pgstat_function_flush_cb() in pgstat_function.c says since
> 5891c7a8ed8f, so that seems like a remnant from the original patch
> that has introduced this inconsistency across its reviews:
> "/* localent always has non-zero content */"

Thanks for looking at it!

Yeah and same in pgstat_subscription_flush_cb(). 

> Your suggestion does not look completely right to me.  There is
> nothing preventing us from using something else than event counters
> since we don't use memcpy() and there is no comparison work, no?  It
> seems to me that we could remove the entire sentence instead.

Do you mean also remove the comments in pgstat_function_flush_cb() and
pgstat_subscription_flush_cb()? Those comments look fine to me given
the places where those pending entries are created meaning in
pgstat_init_function_usage() for the functions and pgstat_report_subscription_error()
and pgstat_report_subscription_conflict() for the subscriptions.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com



pgsql-hackers by date:

Previous
From: Masahiko Sawada
Date:
Subject: Re: long-standing data loss bug in initial sync of logical replication
Next
From: "Zhijie Hou (Fujitsu)"
Date:
Subject: RE: Conflict detection for update_deleted in logical replication