Regardign RecentFlushPtr in WalSndWaitForWal()

shveta malik <shveta.malik@gmail.com>

From: shveta malik <shveta.malik@gmail.com>
To: pgsql-hackers <pgsql-hackers@postgresql.org>
Cc: Robert Haas <robertmhaas@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, shveta malik <shveta.malik@gmail.com>
Date: 2024-02-26T11:46:39Z
Lists: pgsql-hackers
Hi hackers,

I would like to understand why we have code [1] that retrieves
RecentFlushPtr in WalSndWaitForWal() outside of the loop. We utilize
RecentFlushPtr later within the loop, but prior to that, we already
have [2]. Wouldn't [2] alone be sufficient?

Just to check the impact, I ran 'make check-world' after removing [1],
and did not see any issue exposed by the test at-least.

Any thoughts?

[1]:
        /* Get a more recent flush pointer. */
        if (!RecoveryInProgress())
                RecentFlushPtr = GetFlushRecPtr(NULL);
        else
                RecentFlushPtr = GetXLogReplayRecPtr(NULL);

[2]:
                /* Update our idea of the currently flushed position. */
                else if (!RecoveryInProgress())
                        RecentFlushPtr = GetFlushRecPtr(NULL);
                else
                        RecentFlushPtr = GetXLogReplayRecPtr(NULL);

thanks
Shveta



Commits

  1. Remove redundant fetch of the recent flush pointer in WalSndWaitForWal.

  2. Allow logical decoding via the walsender interface.