diff options
| author | Tomas Vondra <tomas.vondra@postgresql.org> | 2023-04-06 17:18:38 +0200 |
|---|---|---|
| committer | Tomas Vondra <tomas.vondra@postgresql.org> | 2023-04-06 17:18:42 +0200 |
| commit | 2820adf7755d2a377546d5b55f5b1a4a39889336 (patch) | |
| tree | 334f61a64955c187476ca65d9732f736a2eeee65 /doc/src | |
| parent | 983ec23007bd83a649af9bc823f13feb0da27e0e (diff) | |
Support long distance matching for zstd compression
zstd compression supports a special mode for finding matched in distant
past, which may result in better compression ratio, at the expense of
using more memory (the window size is 128MB).
To enable this optional mode, use the "long" keyword when specifying the
compression method (--compress=zstd:long).
Author: Justin Pryzby
Reviewed-by: Tomas Vondra, Jacob Champion
Discussion: https://postgr.es/m/20230224191840.GD1653@telsasoft.com
Discussion: https://postgr.es/m/20220327205020.GM28503@telsasoft.com
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/protocol.sgml | 10 | ||||
| -rw-r--r-- | doc/src/sgml/ref/pg_basebackup.sgml | 4 | ||||
| -rw-r--r-- | doc/src/sgml/ref/pg_dump.sgml | 2 |
3 files changed, 13 insertions, 3 deletions
diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml index 8b5e7b1ad7f..b11d9a6ba35 100644 --- a/doc/src/sgml/protocol.sgml +++ b/doc/src/sgml/protocol.sgml @@ -2729,7 +2729,8 @@ psql "dbname=postgres replication=database" -c "IDENTIFY_SYSTEM;" level. Otherwise, it should be a comma-separated list of items, each of the form <replaceable>keyword</replaceable> or <replaceable>keyword=value</replaceable>. Currently, the supported - keywords are <literal>level</literal> and <literal>workers</literal>. + keywords are <literal>level</literal>, <literal>long</literal> and + <literal>workers</literal>. </para> <para> @@ -2747,6 +2748,13 @@ psql "dbname=postgres replication=database" -c "IDENTIFY_SYSTEM;" </para> <para> + The <literal>long</literal> keyword enables long-distance matching + mode, for improved compression ratio, at the expense of higher memory + use. Long-distance mode is supported only for + <literal>zstd</literal>. + </para> + + <para> The <literal>workers</literal> keyword sets the number of threads that should be used for parallel compression. Parallel compression is supported only for <literal>zstd</literal>. diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml index db3ad9cd5eb..79d3e657c32 100644 --- a/doc/src/sgml/ref/pg_basebackup.sgml +++ b/doc/src/sgml/ref/pg_basebackup.sgml @@ -424,8 +424,8 @@ PostgreSQL documentation level. Otherwise, it should be a comma-separated list of items, each of the form <literal>keyword</literal> or <literal>keyword=value</literal>. - Currently, the supported keywords are <literal>level</literal> - and <literal>workers</literal>. + Currently, the supported keywords are <literal>level</literal>, + <literal>long</literal>, and <literal>workers</literal>. The detail string cannot be used when the compression method is specified as a plain integer. </para> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 8de38e0fd0d..e81e35c13b3 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -681,6 +681,8 @@ PostgreSQL documentation as though it had been fed through <application>gzip</application>, <application>lz4</application>, or <application>zstd</application>; but the default is not to compress. + With zstd compression, <literal>long</literal> mode may improve the + compression ratio, at the cost of increased memory use. </para> <para> The tar archive format currently does not support compression at all. |