database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-03 15:22:11 +03:00
Code Activity

Add convenience functions pg_sleep_for and pg_sleep_until.

Browse Source 
Vik Fearing, reviewed by Pavel Stehule and myself
This commit is contained in:
Robert Haas
2014-01-30 15:45:14 -05:00
parent 043f6ff05d
commit 760c770ff6
5 changed files with 23 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
doc/src/sgml/func.sgml
View File

@@ -7664,20 +7664,28 @@ SELECT TIMESTAMP 'now'; -- incorrect for use with DEFAULT
</indexterm>
<para>
The following function is available to delay execution of the server
The following functions are available to delay execution of the server
process:
<synopsis>
pg_sleep(<replaceable>seconds</replaceable>)
pg_sleep_for(<type>interval</>)
pg_sleep_until(<type>timestamp with time zone</>)
</synopsis>
<function>pg_sleep</function> makes the current session's process
sleep until <replaceable>seconds</replaceable> seconds have
elapsed. <replaceable>seconds</replaceable> is a value of type
<type>double precision</>, so fractional-second delays can be specified.
<function>pg_sleep_for</function> is a convenience function for larger
sleep times specified as an <type>interval</>.
<function>pg_sleep_until</function> is a convenience function for when
a specific wake-up time is desired.
For example:
<programlisting>
SELECT pg_sleep(1.5);
SELECT pg_sleep_for('5 minutes');
SELECT pg_sleep_until('tomorrow 03:00');
</programlisting>
</para>
@@ -7686,15 +7694,17 @@ SELECT pg_sleep(1.5);
The effective resolution of the sleep interval is platform-specific;
0.01 seconds is a common value. The sleep delay will be at least as long
as specified. It might be longer depending on factors such as server load.
In particular, <function>pg_sleep_until</function> is not guaranteed to
wake up exactly at the specified time, but it will not wake up any earlier.
</para>
</note>
<warning>
<para>
Make sure that your session does not hold more locks than necessary
when calling <function>pg_sleep</function>. Otherwise other sessions
might have to wait for your sleeping process, slowing down the entire
system.
when calling <function>pg_sleep</function> or its variants. Otherwise
other sessions might have to wait for your sleeping process, slowing down
the entire system.
</para>
</warning>
</sect2>