Skip collecting wal if db is aurora

[caflamand]

Hello!

I'm was trying to run pgmetrics from linux to get metrics for our AWS RDS Aurora Cluster (14.4), but I was getting the following fatal error when trying to do so.

pgmetrics: pg_stat_wal query failed: pq: Function pg_stat_get_wal() is currently not supported for Aurora

Aurora not supporting wal metrics seems to be a known issue for pgmetrics, see below:

pgmetrics/collector/collect.go

Lines 854 to 860 in 35516b5

	func (c *collector) getWalReceiverv96() {
	// skip if Aurora, because the function errors out with:
	// "Function pg_stat_get_wal_receiver() is currently not supported in Aurora"
	if c.isAWSAurora() {
	return
	}

After some investigation, I found that the error was being raised by the getWal() function, which is missing the c.isAWSAurora() check.

pgmetrics/collector/collect.go

Lines 2417 to 2436 in 35516b5

	func (c *collector) getWAL() {
	ctx, cancel := context.WithTimeout(context.Background(), c.timeout)
	defer cancel()
	// pg_stat_wal has only 1 row
	q := `SELECT wal_records, wal_fpi, wal_bytes, wal_buffers_full, wal_write,
	wal_sync, wal_write_time, wal_sync_time,
	COALESCE(EXTRACT(EPOCH FROM stats_reset)::bigint, 0)
	FROM pg_stat_wal
	LIMIT 1`
	var w pgmetrics.WAL
	err := c.db.QueryRowContext(ctx, q).Scan(&w.Records, &w.FPI, &w.Bytes,
	&w.BuffersFull, &w.Write, &w.Sync, &w.WriteTime, &w.SyncTime,
	&w.StatsReset)
	if err != nil {
	log.Fatalf("pg_stat_wal query failed: %v", err)
	}
	c.result.WAL = &w
	}

I recompiled locally with the check and it fixed my issue.

The call to the getWal() function has been introduced more than a year ago. I couldn't find any related issues in the repo, am I the first one to have this issue?

[mdevan]

Thanks for the report and fix. We'll merge/provide a fix in the upcoming release (likely next week).

[mdevan]

Available in release v1.14.0.

(Note: Also use latest pgdash CLI v1.10.0 to send to pgDash server.)