thanos-io/thanos · error

sync

Error message

sync

What it means

Wraps sy.SyncMetas during the compactor's initial metadata sync: downloading/refreshing block metadata from object storage failed (bucket auth, network, corrupt meta.json). The compaction loop cannot plan without a consistent view of the bucket's blocks.

Solutions

1. Check object store connectivity and permissions
2. Inspect wrapped fetcher errors for failing blocks
3. Retry after transient failures

When it happens

Trigger: Thrown at pkg/compact/compact.go:1568 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/6b6532dc5f118cca. Report an issue: GitHub.

Appendix: source

Thrown at pkg/compact/compact.go:1568

							metadata.OutOfOrderChunksNoCompactReason,
							"OutofOrderChunk: marking block with out-of-order series/chunks to as no compact to unblock compaction", g.blocksMarkedForNoCompact); err == nil {
							mtx.Lock()
							finishedAllGroups = false
							mtx.Unlock()
							continue
						}
					}
					errChan <- errors.Wrapf(err, "group %s", g.Key())
					return
				}
			})
		}

		// Blocks that were compacted are garbage collected after each Compaction.
		// However if compactor crashes we need to resolve those on startup.
		level.Info(c.logger).Log("msg", "start initial sync of metas")
		if err := c.sy.SyncMetas(ctx); err != nil {
			return errors.Wrap(err, "sync")
		}

		var ignoreBlocks map[ulid.ULID]struct{}
		if c.blocksCleaner != nil {
			deletedBlocks, err := c.blocksCleaner.DeleteMarkedBlocks(ctx)
			if err != nil {
				return errors.Wrap(err, "cleaning marked blocks")
			}
			ignoreBlocks = deletedBlocks
		}

		level.Info(c.logger).Log("msg", "start of initial garbage collection")
		if err := c.sy.GarbageCollect(ctx, ignoreBlocks); err != nil {
			return errors.Wrap(err, "garbage")
		}

		groups, err := c.grouper.Groups(c.sy.Metas())
		if err != nil {

View on GitHub (pinned to 35b8b99117)