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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2019-01-26 14:15:42 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2019-01-26 14:15:42 -0500 |
| commit | 6d3ede5f1c654f923b2767b0b0c3b09569adaa18 (patch) | |
| tree | 6407383b0ce5afe73494ba06be268782cf27f55a /doc/src | |
| parent | 1e4730c639acb967b8e40e6f33e81ebe1721ea5f (diff) | |
| download | postgresql-6d3ede5f1c654f923b2767b0b0c3b09569adaa18.tar.gz postgresql-6d3ede5f1c654f923b2767b0b0c3b09569adaa18.zip | |
Fix psql's "\g target" meta-command to work with COPY TO STDOUT.
Previously, \g would successfully execute the COPY command, but
the target specification if any was ignored, so that the data was
always dumped to the regular query output target. This seems like
a clear bug, so let's not just fix it but back-patch it.
While at it, adjust the documentation for \copy to recommend
"COPY ... TO STDOUT \g foo" as a plausible alternative.
Back-patch to 9.5. The problem exists much further back, but the
code associated with \g was refactored enough in 9.5 that we'd
need a significantly different patch for 9.4, and it doesn't
seem worth the trouble.
Daniel Vérité, reviewed by Fabien Coelho
Discussion: https://postgr.es/m/15dadc39-e050-4d46-956b-dcc4ed098753@manitou-mail.org
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/psql-ref.sgml | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml index 6c76cf2f001..d7539ae7439 100644 --- a/doc/src/sgml/ref/psql-ref.sgml +++ b/doc/src/sgml/ref/psql-ref.sgml @@ -1037,10 +1037,24 @@ testdb=> <tip> <para> - This operation is not as efficient as the <acronym>SQL</acronym> - <command>COPY</command> command because all data must pass - through the client/server connection. For large - amounts of data the <acronym>SQL</acronym> command might be preferable. + Another way to obtain the same result as <literal>\copy + ... to</literal> is to use the <acronym>SQL</acronym> <literal>COPY + ... TO STDOUT</literal> command and terminate it + with <literal>\g <replaceable>filename</replaceable></literal> + or <literal>\g |<replaceable>program</replaceable></literal>. + Unlike <literal>\copy</literal>, this method allows the command to + span multiple lines; also, variable interpolation and backquote + expansion can be used. + </para> + </tip> + + <tip> + <para> + These operations are not as efficient as the <acronym>SQL</acronym> + <command>COPY</command> command with a file or program data source or + destination, because all data must pass through the client/server + connection. For large amounts of data the <acronym>SQL</acronym> + command might be preferable. </para> </tip> |