How to check content of prepared statement in pg_stat_activity.query field

Question

Currently, I'm checking long running query in PostgreSQL.

To check this, I queried the command below:

SELECT pid, waiting, query_start, substr(query, 0, 50)
FROM pg_stat_activity
ORDER BY query_start
LIMIT 30;

And I get:

  pid  | waiting |          query_start          |                              substr
-------+---------+-------------------------------+------------------------------------------------------------------
 26797 | f       | 2015-07-06 12:44:04.418403+00 | SELECT * FROM "projects" WHERE "projects"."id" = $1 LIMIT 1
 ...

To analyse this long running query, I want to check the content of $1 of this prepared statement.

Are there any way to get this?

Answer 1

You will not get this info from pg_stat_activity, but you may get the full query from slow query log.