From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tatsuo Ishii <ishii@sraoss.co.jp>
Cc: pgsql-docs@lists.postgresql.org
Subject: Re: pg_wal_lsn_diff
Date: Sat, 06 Feb 2021 11:57:56 -0500
Message-ID: <190699.1612630676@sss.pgh.pa.us> (raw)
In-Reply-To: <20210206.151125.960423226279810864.t-ishii@sraoss.co.jp>
References: <20210206.151125.960423226279810864.t-ishii@sraoss.co.jp>
Tatsuo Ishii <ishii@sraoss.co.jp> writes:
> According to the pg_wal_lsn_diff manual:
> pg_wal_lsn_diff ( lsn pg_lsn, lsn pg_lsn ) Γ慨鯖 numeric
> Calculates the difference in bytes between two write-ahead log
> locations. This can be used with pg_stat_replication or some of
> the functions shown in Table 9.87 to get the replication lag.
> It's not clear whether its return value is (first arg - second arg) or
> (second arg - first arg). The order matters because the return value
> could have a sign (it actually does first arg - second arg). Attached
> is a patch to fix the description.
+1 for fixing that. Two notes though: first, your text doesn't agree
with the prototype ("ls1" should be "lsn1"), and second, I think it
would read better if you didn't split the phrase "difference in bytes".
That is,
- Calculates the difference in bytes between two write-ahead log
+ Calculates the difference in bytes (lsn1 - lsn2) between two write-ahead log
Also maybe you should use the <parameter>lsn1</parameter> markup
in the text.
regards, tom lane
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To: pgsql-docs@postgresql.org
Cc: tgl@sss.pgh.pa.us, ishii@sraoss.co.jp, pgsql-docs@lists.postgresql.org
Subject: Re: pg_wal_lsn_diff
In-Reply-To: <190699.1612630676@sss.pgh.pa.us>
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