Обсуждение: pg_wal_lsn_diff
According to the pg_wal_lsn_diff manual: pg_wal_lsn_diff ( lsn pg_lsn, lsn pg_lsn ) → 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. Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index b7150510ab..2870692164 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -25102,11 +25102,11 @@ SELECT collation for ('foo' COLLATE "de_DE"); <indexterm> <primary>pg_wal_lsn_diff</primary> </indexterm> - <function>pg_wal_lsn_diff</function> ( <parameter>lsn</parameter> <type>pg_lsn</type>, <parameter>lsn</parameter><type>pg_lsn</type> ) + <function>pg_wal_lsn_diff</function> ( <parameter>lsn1</parameter> <type>pg_lsn</type>, <parameter>lsn2</parameter><type>pg_lsn</type> ) <returnvalue>numeric</returnvalue> </para> <para> - Calculates the difference in bytes between two write-ahead log + Calculates the difference (ls1 - ls2) in bytes between two write-ahead log locations. This can be used with <structname>pg_stat_replication</structname> or some of the functions shown in <xref linkend="functions-admin-backup-table"/> to
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 ) $B"*(B 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
> +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. Thank you for the review. Attached is the revised patch. So do you think we should back-patch to existing stable branches? The reason I am asking is, the doc format for v12 and before use very simple description and if we apply the same description of this patch to those branche, the description level for the function may look different from other functions. (I am not against to apply to v13). Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index b7150510ab..1ab31a9056 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -25102,11 +25102,11 @@ SELECT collation for ('foo' COLLATE "de_DE"); <indexterm> <primary>pg_wal_lsn_diff</primary> </indexterm> - <function>pg_wal_lsn_diff</function> ( <parameter>lsn</parameter> <type>pg_lsn</type>, <parameter>lsn</parameter><type>pg_lsn</type> ) + <function>pg_wal_lsn_diff</function> ( <parameter>lsn1</parameter> <type>pg_lsn</type>, <parameter>lsn2</parameter><type>pg_lsn</type> ) <returnvalue>numeric</returnvalue> </para> <para> - Calculates the difference in bytes between two write-ahead log + Calculates the difference in bytes (<parameter>lsn1</parameter> - <parameter>lsn2</parameter>) between two write-aheadlog locations. This can be used with <structname>pg_stat_replication</structname> or some of the functions shown in <xref linkend="functions-admin-backup-table"/> to
Tatsuo Ishii <ishii@sraoss.co.jp> writes: > So do you think we should back-patch to existing stable branches? I'd just fix HEAD and v13. The earlier branches are not friendly at all to long function descriptions. regards, tom lane
> I'd just fix HEAD and v13. The earlier branches are not friendly > at all to long function descriptions. +1 from me. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp
>> I'd just fix HEAD and v13. The earlier branches are not friendly >> at all to long function descriptions. > > +1 from me. Pushed to HEAD and v13. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp