diff options
| -rw-r--r-- | doc/src/sgml/ref/pgbench.sgml | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml index ab252d9fc74..5ca9de63fa3 100644 --- a/doc/src/sgml/ref/pgbench.sgml +++ b/doc/src/sgml/ref/pgbench.sgml @@ -1188,10 +1188,8 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d <variablelist> <varlistentry id="pgbench-metacommand-gset"> - <term> - <literal>\gset [<replaceable>prefix</replaceable>]</literal> - <literal>\aset [<replaceable>prefix</replaceable>]</literal> - </term> + <term><literal>\gset [<replaceable>prefix</replaceable>]</literal></term> + <term><literal>\aset [<replaceable>prefix</replaceable>]</literal></term> <listitem> <para> @@ -1203,16 +1201,17 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d 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. + if provided. If the query returns zero or multiple rows, an error is raised. </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. + if provided. If a query returns no rows, no assignment is made. + This can be detected by initializing the variable beforehand with + a value the query cannot return, then checking whether it changes. + If a query returns more than one row, the last values is kept. </para> <para> |