Method Close

tsdb/head.go:1871–1900

Close flushes the WAL and closes the head. It also takes a snapshot of in-memory chunks if enabled.

()

// Close flushes the WAL and closes the head.
// It also takes a snapshot of in-memory chunks if enabled.
func (h *Head) Close() error {
	h.closedMtx.Lock()
	defer h.closedMtx.Unlock()
	h.closed = true

	// Stop the background series_state.json writer.
	if h.opts.EnableFastStartup && h.seriesStateQuit != nil {
		close(h.seriesStateQuit)
		h.seriesStateWg.Wait()
		h.seriesStateQuit = nil
		// Flush the final clean state.
		h.writeSeriesState(true)
	}

	// mmap all but last chunk in case we're performing snapshot since that only
	// takes samples from most recent head chunk.
	h.mmapHeadChunks()

	errs := h.chunkDiskMapper.Close()
	if h.wal != nil {
		errs = errors.Join(errs, h.wal.Close())
	}
	if h.wbl != nil {
		errs = errors.Join(errs, h.wbl.Close())
	}
	if errs == nil && h.opts.EnableMemorySnapshotOnShutdown {
		errs = errors.Join(errs, h.performChunkSnapshot())
	}
	return errs
}

// String returns an human readable representation of the TSDB head. It's important to
// keep this function in order to avoid the struct dump when the head is stringified in