thanos-io/thanos · error

rewrite block

Error message

rewrite block

What it means

The rewrite step inside block Repair failed while copying series/chunks into the new block (via rewrite with the ignore function). Indicates corrupt source index/chunks or an error from the chunk iterator; the partially written result is discarded.

Solutions

1. Inspect the underlying rewrite error for the failing series
2. Verify source block integrity
3. Re-download the block and retry repair

When it happens

Trigger: Thrown at pkg/block/index.go:472 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/67da7af5749688db. Report an issue: GitHub.

Appendix: source

Thrown at pkg/block/index.go:472

		return resid, errors.Wrap(err, "open chunk writer")
	}
	defer runutil.CloseWithErrCapture(&err, chunkw, "repair chunk writer")

	indexw, err := index.NewWriter(context.TODO(), filepath.Join(resdir, IndexFilename))
	if err != nil {
		return resid, errors.Wrap(err, "open index writer")
	}
	defer runutil.CloseWithErrCapture(&err, indexw, "repair index writer")

	// TODO(fabxc): adapt so we properly handle the version once we update to an upstream
	// that has multiple.
	resmeta := *meta
	resmeta.ULID = resid
	resmeta.Stats = tsdb.BlockStats{} // Reset stats.
	resmeta.Thanos.Source = source    // Update source.

	if err := rewrite(ctx, logger, indexr, chunkr, indexw, chunkw, &resmeta, ignoreChkFns); err != nil {
		return resid, errors.Wrap(err, "rewrite block")
	}
	resmeta.Thanos.SegmentFiles = GetSegmentFiles(resdir)
	if err := resmeta.WriteToDir(logger, resdir); err != nil {
		return resid, err
	}
	// TSDB may rewrite metadata in bdir.
	// TODO: This is not needed in newer TSDB code. See https://github.com/prometheus/tsdb/pull/637.
	if err := meta.WriteToDir(logger, bdir); err != nil {
		return resid, err
	}
	return resid, nil
}

var castagnoli = crc32.MakeTable(crc32.Castagnoli)

func IgnoreCompleteOutsideChunk(mint, maxt int64, _, curr *chunks.Meta) (bool, error) {
	if curr.MinTime > maxt || curr.MaxTime < mint {
		// "Complete" outsider. Ignore.

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