Error "WAL control functions cannot be executed during recovery" for pg_replication_slots

[dan-aksenov]

What did you do?
Simply running exporter 0.0.1-rev (built with go1.15.8)

What did you expect to see?
I expect no errors

What did you see instead? Under which circumstances?

ERROR:  recovery is in progress
HINT:  WAL control functions cannot be executed during recovery.
STATEMENT:
                                SELECT slot_name, database, active, pg_wal_lsn_diff(pg_current_wal_lsn(), restart_lsn)
                                FROM pg_replication_slots

Environment

• System information:

  insert output of uname -srm here
  Linux 5.4.0-66-generic x86_64

• postgres_exporter version:

  insert output of postgres_exporter --version here
  postgres_exporter 0.0.1-rev (built with go1.15.8)

• postgres_exporter flags:

/opt/postgres_exporter/postgres_exporter --web.listen-address=:9187 --log.level=warn --extend.query-path=/opt/postgres_exporter/queries.yaml

• PostgresSQL version:

  insert PostgreSQL version here
  11.8

• Logs:

insert logs relevant to the issue here

While looking here

postgres_exporter/cmd/postgres_exporter/postgres_exporter.go

Lines 431 to 443 in 134e908

	"pg_replication_slots": {
	{
	semver.MustParseRange(">=9.4.0 <10.0.0"),
	`
	SELECT slot_name, database, active, pg_xlog_location_diff(pg_current_xlog_location(), restart_lsn)
	FROM pg_replication_slots
	`,
	},
	{
	semver.MustParseRange(">=10.0.0"),
	`
	SELECT slot_name, database, active, pg_wal_lsn_diff(pg_current_wal_lsn(), restart_lsn)
	FROM pg_replication_slots

I see no pg_is_in_recovery check

[michael-todorovic]

Hello,
We identified the issue at my company with standby clusters and we're currently working on a fix ;) I was forking the repo to send the PR today or tomorrow

[maudrid]

Thanks, this fixed my issue also.

[lcaflc]

Hi all,

Any reason the fix is still not merged into upstream version ? We can workaround this error in monitoring system but this is not clean where this can be simply fixed in the exporter.

Thanks.

[mhbahmani]

Hi,

This issue is open since 2021! I was wondering when it gets fixed.
I encountered this issue on postgresql 14.

Thanks.