doc: add example of using pg_dump with GNU split and gzip

This is only possible with GNU split, not other versions like BSD split.

Reported-by: [email protected]
Discussion: https://postgr.es/m/162653459215.701.6323855956817776386@wrigleys.postgresql.org

Backpatch-through: 9.6

diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml
index 8c9186d277fd62efdab1f3ad2f249fc8e8f7fdea..cba32b6eb3e521f702e5304ef4f489b77ff4114b 100644 (file)
--- a/doc/src/sgml/backup.sgml
+++ b/doc/src/sgml/backup.sgml
@@ -273,10 +273,10 @@ cat filename.gz | gunzip | psql 
      The split command
      allows you to split the output into smaller files that are
      acceptable in size to the underlying file system. For example, to
-     make chunks of 1 megabyte:
+     make 2 gigabyte chunks:
 
 
-pg_dump dbname | split -b 1m - filename
+pg_dump dbname | split -b 2G - filename
 
 
      Reload with:
@@ -284,6 +284,15 @@ pg_dump dbname | split -b 1m - 
 
 cat filename* | psql dbname
 
+
+     If using GNU split, it is possible to
+     use it and gzip together:
+
+
+pg_dump dbname | split -b 2G --filter='gzip > $FILE.gz'
+
+
+     It can be restored using zcat.