diff options
| author | Daniel Gustafsson <dgustafsson@postgresql.org> | 2023-08-29 11:30:11 +0200 |
|---|---|---|
| committer | Daniel Gustafsson <dgustafsson@postgresql.org> | 2023-08-29 11:30:11 +0200 |
| commit | f347ec76e2a227e5c5b5065cce7adad16d58d209 (patch) | |
| tree | 0d03e7a4caa335a0b9ae014299ccabbac8486c3f /src/bin/psql/t/001_basic.pl | |
| parent | 95fff2abee66c16ca3609b3c1638cbd553730a90 (diff) | |
Allow \watch queries to stop on minimum rows returned
When running a repeat query with \watch in psql, it can be
helpful to be able to stop the watch process when the query
no longer returns the expected amount of rows. An example
would be to watch for the presence of a certain event in
pg_stat_activity and stopping when the event is no longer
present, or to watch an index creation and stop when the
index is created.
This adds a min_rows=MIN parameter to \watch which can be
set to a non-negative integer, and the watch query will
stop executing when it returns less than MIN rows.
Author: Greg Sabino Mullane <htamfids@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CAKAnmmKStATuddYxP71L+p0DHtp9Rvjze3XRoy0Dyw67VQ45UA@mail.gmail.com
Diffstat (limited to 'src/bin/psql/t/001_basic.pl')
| -rw-r--r-- | src/bin/psql/t/001_basic.pl | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/src/bin/psql/t/001_basic.pl b/src/bin/psql/t/001_basic.pl index 9ac27db2120..5398a1dbf3d 100644 --- a/src/bin/psql/t/001_basic.pl +++ b/src/bin/psql/t/001_basic.pl @@ -355,6 +355,29 @@ psql_like( psql_like($node, sprintf('SELECT 1 \watch c=3 i=%g', 0.01), qr/1\n1\n1/, '\watch with 3 iterations'); +# Check \watch minimum row count +psql_fails_like( + $node, + 'SELECT 3 \watch m=x', + qr/incorrect minimum row count/, + '\watch, invalid minimum row setting'); + +psql_fails_like( + $node, + 'SELECT 3 \watch m=1 min_rows=2', + qr/minimum row count specified more than once/, + '\watch, minimum rows is specified more than once'); + +psql_like( + $node, + q{with x as ( + select now()-backend_start AS howlong + from pg_stat_activity + where pid = pg_backend_pid() + ) select 123 from x where howlong < '2 seconds' \watch i=0.5 m=2}, + qr/^123$/, + '\watch, 2 minimum rows'); + # Check \watch errors psql_fails_like( $node, |