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| author | Michael Paquier <michael@paquier.xyz> | 2020-04-03 11:45:15 +0900 |
|---|---|---|
| committer | Michael Paquier <michael@paquier.xyz> | 2020-04-03 11:45:15 +0900 |
| commit | 9d8ef98800bd291de145fb1be41f0868546e02ab (patch) | |
| tree | 4862d78e2ae452c690f2bf4ccbe74a4bf547677f /doc/src | |
| parent | ed7a5095716ee498ecc406e1b8d5ab92c7662d10 (diff) | |
| download | postgresql-9d8ef98800bd291de145fb1be41f0868546e02ab.tar.gz postgresql-9d8ef98800bd291de145fb1be41f0868546e02ab.zip | |
Add support for \aset in pgbench
This option is similar to \gset, except that it is able to store all
results from combined SQL queries into separate variables. If a query
returns multiple rows, the last result is stored and if a query returns
no rows, nothing is stored.
While on it, add a TAP test for \gset to check for a failure when a
query returns multiple rows.
Author: Fabien Coelho
Reviewed-by: Ibrar Ahmed, Michael Paquier
Discussion: https://postgr.es/m/alpine.DEB.2.21.1904081914200.2529@lancre
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/pgbench.sgml | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml index 41b3880c91f..58a2aa3bf20 100644 --- a/doc/src/sgml/ref/pgbench.sgml +++ b/doc/src/sgml/ref/pgbench.sgml @@ -1057,18 +1057,29 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d <varlistentry id='pgbench-metacommand-gset'> <term> <literal>\gset [<replaceable>prefix</replaceable>]</literal> + <literal>\aset [<replaceable>prefix</replaceable>]</literal> </term> <listitem> <para> - This command may be used to end SQL queries, taking the place of the + These commands may be used to end SQL queries, taking the place of the terminating semicolon (<literal>;</literal>). </para> <para> - When this command is used, the preceding SQL query is expected to - return one row, the columns of which are stored into variables named after - column names, and prefixed with <replaceable>prefix</replaceable> if provided. + When the <literal>\gset</literal> command is used, the preceding SQL query is + expected to return one row, the columns of which are stored into variables + named after column names, and prefixed with <replaceable>prefix</replaceable> + if provided. + </para> + + <para> + When the <literal>\aset</literal> command is used, all combined SQL queries + (separated by <literal>\;</literal>) have their columns stored into variables + named after column names, and prefixed with <replaceable>prefix</replaceable> + if provided. If a query returns no row, no assignment is made and the variable + can be tested for existence to detect this. If a query returns more than one + row, the last value is kept. </para> <para> @@ -1077,6 +1088,8 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d <replaceable>p_two</replaceable> and <replaceable>p_three</replaceable> with integers from the third query. The result of the second query is discarded. + The result of the two last combined queries are stored in variables + <replaceable>four</replaceable> and <replaceable>five</replaceable>. <programlisting> UPDATE pgbench_accounts SET abalance = abalance + :delta @@ -1085,6 +1098,7 @@ UPDATE pgbench_accounts -- compound of two queries SELECT 1 \; SELECT 2 AS two, 3 AS three \gset p_ +SELECT 4 AS four \; SELECT 5 AS five \aset </programlisting> </para> </listitem> |