database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-02 04:21:28 +03:00
Code Activity

Add support for piping COPY to/from an external program.

Browse Source 
This includes backend "COPY TO/FROM PROGRAM '...'" syntax, and corresponding
psql \copy syntax. Like with reading/writing files, the backend version is
superuser-only, and in the psql version, the program is run in the client.

In the passing, the psql \copy STDIN/STDOUT syntax is subtly changed: if you
the stdin/stdout is quoted, it's now interpreted as a filename. For example,
"\copy foo from 'stdin'" now reads from a file called 'stdin', not from
standard input. Before this, there was no way to specify a filename called
stdin, stdout, pstdin or pstdout.

This creates a new function in pgport, wait_result_to_str(), which can
be used to convert the exit status of a process, as returned by wait(3),
to a human-readable string.

Etsuro Fujita, reviewed by Amit Kapila.
This commit is contained in:
Heikki Linnakangas
2013-02-27 18:17:21 +02:00
parent 73dc003bee
commit 3d009e45bd
21 changed files with 584 additions and 152 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
doc/src/sgml/ref/psql-ref.sgml
View File

@@ -830,7 +830,7 @@ testdb=>
<varlistentry id="APP-PSQL-meta-commands-copy">
<term><literal>\copy { <replaceable class="parameter">table</replaceable> [ ( <replaceable class="parameter">column_list</replaceable> ) ] | ( <replaceable class="parameter">query</replaceable> ) }
{ <literal>from</literal> | <literal>to</literal> }
{ <replaceable class="parameter">filename</replaceable> | stdin | stdout | pstdin | pstdout }
{ <replaceable class="parameter">'filename'</replaceable> | program <replaceable class="parameter">'command'</replaceable> | stdin | stdout | pstdin | pstdout }
[ [ with ] ( <replaceable class="parameter">option</replaceable> [, ...] ) ]</literal></term>
<listitem>
@@ -847,16 +847,14 @@ testdb=&gt;
</para>
<para>
The syntax of the command is similar to that of the
<acronym>SQL</acronym> <xref linkend="sql-copy">
command, and
<replaceable class="parameter">option</replaceable>
must indicate one of the options of the
<acronym>SQL</acronym> <xref linkend="sql-copy"> command.
Note that, because of this,
special parsing rules apply to the <command>\copy</command>
command. In particular, the variable substitution rules and
backslash escapes do not apply.
When <literal>program</> is specified,
<replaceable class="parameter">command</replaceable> is
executed by <application>psql</application> and the data from
or to <replaceable class="parameter">command</replaceable> is
routed between the server and the client.
This means that the execution privileges are those of
the local user, not the server, and no SQL superuser
privileges are required.
</para>
<para><literal>\copy ... from stdin | to stdout</literal>
@@ -870,6 +868,19 @@ testdb=&gt;
for populating tables in-line within a SQL script file.
</para>
<para>
The syntax of the command is similar to that of the
<acronym>SQL</acronym> <xref linkend="sql-copy">
command, and
<replaceable class="parameter">option</replaceable>
must indicate one of the options of the
<acronym>SQL</acronym> <xref linkend="sql-copy"> command.
Note that, because of this,
special parsing rules apply to the <command>\copy</command>
command. In particular, the variable substitution rules and
backslash escapes do not apply.
</para>
<tip>
<para>
This operation is not as efficient as the <acronym>SQL</acronym>