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I'm supporting a new system that's going live next month. I'm trying to have PostgreSQL log any long-running (over 1 second) queries to the error log. I've set the following parameters:

log_duration: 1
log_min_duration_statement: 1000
log_statement: all

However, the DB seems to be writing all queries to the log; e.g.:

2025-11-20 15:49:42 UTC:100.126.191.233(49316):foo@bar:[63907]:LOG:  duration: 0.080 ms
2025-11-20 15:49:42 UTC:100.126.191.233(49316):foo@bar:[63907]:LOG:  duration: 0.096 ms
2025-11-20 15:49:42 UTC:100.126.191.233(49316):foo@bar:[63907]:LOG:  execute <unnamed>: UPDATE [...]
2025-11-20 15:49:42 UTC:100.126.191.233(49316):foo@bar:[63907]:DETAIL:  Parameters: $1 = [...]
2025-11-20 15:49:42 UTC:100.126.191.233(49316):foo@bar:[63907]:LOG:  duration: 0.467 ms
2025-11-20 15:49:42 UTC:100.126.169.109(36852):foo@bar:[63912]:LOG:  duration: 0.125 ms
2025-11-20 15:49:42 UTC:100.126.169.109(36852):foo@bar:[63912]:LOG:  execute S_112/C_144: SELECT [...]
2025-11-20 15:49:42 UTC:100.126.169.109(36852):foo@bar:[63912]:DETAIL:  Parameters: $1 = [...]
2025-11-20 15:49:42 UTC:100.126.169.109(36852):foo@bar:[63912]:LOG:  duration: 0.036 ms
2025-11-20 15:49:42 UTC:100.126.191.233(49316):foo@bar:[63907]:LOG:  duration: 0.008 ms
2025-11-20 15:49:42 UTC:100.126.191.233(49316):foo@bar:[63907]:LOG:  execute S_13: COMMIT

(all proprietary information has been redacted)

What am I doing wrong? This is Aurora PostgreSQL 17.5

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2 Answers 2

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OK, figured out the problem; apparently setting log_statement: all actually logs all statements, no matter the duration.

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You're seeing every query in the logs because of one parameter:

log_statement = all

This setting forces PostgreSQL to log every SQL statement, regardless of how long it takes. It overrides your log_min_duration_statement setting, so even statements that take less than a millisecond will still appear in the logs.

In addition, you have:

log_duration = 1

log_duration logs the duration for all statements. It doesn’t filter — it only controls whether durations are printed. So with these two settings combined, PostgreSQL logs:

every statement (log_statement = all)

plus the duration of every statement (log_duration = 1)

That's exactly why your logs are full of extremely fast queries like 0.008 ms.

If your goal is to log only queries that take longer than 1 second, you should disable log_statement and rely entirely on log_min_duration_statement:

log_statement = none log_min_duration_statement = 1000 # log only statements taking > 1 second log_duration = off # optional, removes duration for fast queries

On Aurora PostgreSQL, make these changes in the parameter group and reboot if required.

Once you remove log_statement = all, only the slow queries (those exceeding 1 second) will appear in the logs.

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