compact: retry on sync metas error

CHANGELOG.md

@@ -23,6 +23,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#5801](https://github.com/thanos-io/thanos/pull/5801) Store: add a new limiter `--store.grpc.downloaded-bytes-limit` that limits the number of bytes downloaded in each Series/LabelNames/LabelValues call. Use `thanos_bucket_store_postings_size_bytes` for determining the limits.
 - [#5839](https://github.com/thanos-io/thanos/pull/5839) Receive: Add parameter `--tsdb.out-of-order.time-window` to set time window for experimental out-of-order samples ingestion. Disabled by default (set to 0s). Please note if you enable this option and you use compactor, make sure you set the `--enable-vertical-compaction` flag, otherwise you might risk compactor halt.
 - [#5836](https://github.com/thanos-io/thanos/pull/5836) Receive: Add hidden flag `tsdb.memory-snapshot-on-shutdown` to enable experimental TSDB feature to snapshot on shutdown. This is intended to speed up receiver restart.
+- [#5865](https://github.com/thanos-io/thanos/pull/5865) Compact: Retry on sync metas error.
 
 ### Changed
 

cmd/thanos/compact.go

@@ -576,6 +576,15 @@ func runCompact(
 				return runutil.Repeat(conf.progressCalculateInterval, ctx.Done(), func() error {
 
 					if err := sy.SyncMetas(ctx); err != nil {
+						// The RetryError signals that we hit an retriable error (transient error, no connection).
+						// You should alert on this being triggered too frequently.
+						if compact.IsRetryError(err) {
+							level.Error(logger).Log("msg", "retriable error", "err", err)
+							compactMetrics.retried.Inc()
+
+							return nil
+						}
+
 						return errors.Wrapf(err, "could not sync metas")
 					}