diff options
author | Peter Eisentraut | 2023-11-06 07:17:54 +0000 |
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committer | Peter Eisentraut | 2023-11-06 08:16:00 +0000 |
commit | 6ceec8a1fe7a5028b29bbfe402f645f6fea5fb90 (patch) | |
tree | dee0752bd9a7adf33ecc9afc0d54473c3248c183 | |
parent | 93c85db3b5b8d8d15b10b4c66a0e6961028470d4 (diff) |
doc: pg_resetwal: Add comments how the multipliers are derived
Reviewed-by: Aleksander Alekseev <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/[email protected]
-rw-r--r-- | doc/src/sgml/ref/pg_resetwal.sgml | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/doc/src/sgml/ref/pg_resetwal.sgml b/doc/src/sgml/ref/pg_resetwal.sgml index 08cd3ce5fc..cf9c7e70f2 100644 --- a/doc/src/sgml/ref/pg_resetwal.sgml +++ b/doc/src/sgml/ref/pg_resetwal.sgml @@ -166,7 +166,8 @@ PostgreSQL documentation <command>pg_resetwal</command> is unable to determine appropriate values by reading <filename>pg_control</filename>. Safe values can be determined as described below. For values that take numeric arguments, hexadecimal - values can be specified by using the prefix <literal>0x</literal>. + values can be specified by using the prefix <literal>0x</literal>. Note + that these instructions only apply with the standard block size of 8 kB. </para> <variablelist> @@ -189,6 +190,7 @@ PostgreSQL documentation greatest file name in the same directory. The file names are in hexadecimal. </para> + <!-- XXX: Should there be a multiplier, similar to the other options? --> </listitem> </varlistentry> @@ -272,6 +274,7 @@ PostgreSQL documentation names are in hexadecimal, so the easiest way to do this is to specify the option value in hexadecimal and append four zeroes. </para> + <!-- 65536 = SLRU_PAGES_PER_SEGMENT * BLCKSZ / sizeof(MultiXactOffset) --> </listitem> </varlistentry> @@ -306,6 +309,7 @@ PostgreSQL documentation The file names are in hexadecimal. There is no simple recipe such as the ones for other options of appending zeroes. </para> + <!-- 52352 = SLRU_PAGES_PER_SEGMENT * floor(BLCKSZ/20) * 4; see multixact.c --> </listitem> </varlistentry> @@ -354,6 +358,7 @@ PostgreSQL documentation in <filename>pg_xact</filename>, <literal>-u 0x700000</literal> will work (five trailing zeroes provide the proper multiplier). </para> + <!-- 1048576 = SLRU_PAGES_PER_SEGMENT * BLCKSZ * CLOG_XACTS_PER_BYTE --> </listitem> </varlistentry> @@ -375,6 +380,7 @@ PostgreSQL documentation in <filename>pg_xact</filename>, <literal>-x 0x1200000</literal> will work (five trailing zeroes provide the proper multiplier). </para> + <!-- 1048576 = SLRU_PAGES_PER_SEGMENT * BLCKSZ * CLOG_XACTS_PER_BYTE --> </listitem> </varlistentry> </variablelist> |