How do I get the SQL statement in a trigger?

Hi

2018-05-10 12:23 GMT+02:00 a <372660931@qq.com>:

Hi I would like to write a trigger that recorded every sql statement under
the effected entry. So if it is possible to retrieve the sql statement
within a trigger??

You can read a tom command from pg_stat_activity table

 postgres=# select query from pg_stat_activity where pid = pg_backend_pid();
+------------------------------------------------------------------+
|                              query                               |
+------------------------------------------------------------------+
| select query from pg_stat_activity where pid = pg_backend_pid(); |
+------------------------------------------------------------------+
(1 row)

But this information is available only for top level query.

Regards

Pavel

Thanks a lot, would you please be so kind to tell me more about what is top level query??

------------------ Original message ------------------
From: "Pavel Stehule";
Sendtime: Thursday, May 10, 2018 6:38 PM
To: "a"<372660931@qq.com>;
Cc: "pgsql-general";
Subject: Re: How do I get the SQL statement in a trigger?

Hi

2018-05-10 12:23 GMT+02:00 a <372660931@qq.com>:
Hi I would like to write a trigger that recorded every sql statement under the effected entry. So if it is possible to retrieve the sql statement within a trigger??

You can read a tom command from pg_stat_activity table

 postgres=# select query from pg_stat_activity where pid = pg_backend_pid();
+------------------------------------------------------------------+
|                              query                               |
+------------------------------------------------------------------+
| select query from pg_stat_activity where pid = pg_backend_pid(); |
+------------------------------------------------------------------+
(1 row)

But this information is available only for top level query.

Regards

Pavel

2018-05-10 12:42 GMT+02:00 a <372660931@qq.com>:

Thanks a lot, would you please be so kind to tell me more about what is top
level query??

for example - if you run some queries from PLpgSQL functions (triggers),
then these queries are not top queries.

Regards

Pavel

Querying over pg_stat_activity with clauses in a trigger can be quite
expensive if your write transaction rate is high.

You may want to look into the current_query() function documented at
https://www.postgresql.org/docs/current/static/functions-info.html

On 10/05/18 11:44, Pavel Stehule wrote:

2018-05-10 12:42 GMT+02:00 a <372660931@qq.com <mailto:372660931@qq.com>>:

Thanks a lot, would you please be so kind to tell me more about what
is top level query??

for example - if you run some queries from PLpgSQL functions (triggers),
then these queries are not top queries.

Regards

Pavel

------------------ Original message ------------------
*From:* "Pavel Stehule"__;
*Sendtime:* Thursday, May 10, 2018 6:38 PM
*To:* "a"<372660931@qq.com <mailto:372660931@qq.com>>;
*Cc:* "pgsql-general"__;
*Subject:* Re: How do I get the SQL statement in a trigger?

Hi

2018-05-10 12:23 GMT+02:00 a <372660931@qq.com
<mailto:372660931@qq.com>>:

Hi I would like to write a trigger that recorded every sql
statement under the effected entry. So if it is possible to
retrieve the sql statement within a trigger??

You can read a tom command from pg_stat_activity table

 postgres=# select query from pg_stat_activity where pid =
pg_backend_pid();
+------------------------------------------------------------------+
|                              query       |
+------------------------------------------------------------------+
| select query from pg_stat_activity where pid = pg_backend_pid(); |
+------------------------------------------------------------------+
(1 row)

But this information is available only for top level query.

Regards

Pavel

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Regards

Fabio Ugo Venchiarutti
Data Services Department
Ocado Technology

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2018-05-10 12:50 GMT+02:00 Fabio Ugo Venchiarutti <f.venchiarutti@ocado.com>
:

Querying over pg_stat_activity with clauses in a trigger can be quite
expensive if your write transaction rate is high.

You may want to look into the current_query() function documented at
https://www.postgresql.org/docs/current/static/functions-info.html

sure - it is better - forgot it

Regards

Pavel