Compaction backed off XXX times

Users Dgraph
1

To reclaim space (because of this bug: Vlog files use lots of disk space: Add option to set LSMOnly option when opening p dir - #14 by llooper-dev) I’m currently exporting and importing the database. While exporting the following messages appeared in the alpha log:

I0119 20:17:11.119995       1 log.go:34] Export Sending batch of size: 120 MB.
I0119 20:17:13.887918       1 log.go:34] Compaction backed off 194000 times
I0119 20:17:13.898207       1 log.go:34] Compaction backed off 194000 times
I0119 20:17:13.974832       1 log.go:34] Compaction backed off 194000 times
I0119 20:17:14.019617       1 log.go:34] Compaction backed off 194000 times
I0119 20:17:22.145165       1 log.go:34] Export Sending batch of size: 121 MB.
I0119 20:17:25.625353       1 log.go:34] Block cache metrics: hit: 287293 miss: 23915702 keys-added: 14080106 keys-updated: 7167 keys-evicted: 484997 cost-added: 61428296492 cost-evicted: 2104063211 sets-dropped: 0 sets-rejected: 9827686 gets-dropped: 3264 gets-kept: 23679872 gets-total: 24202995 hit-ratio: 0.01
I0119 20:17:33.888656       1 log.go:34] Export Time elapsed: 02h58m25s, bytes sent: 105 GiB, speed: 10 MiB/sec, jemalloc: 52 GiB
I0119 20:17:34.086876       1 log.go:34] Export Sending batch of size: 119 MB.
I0119 20:17:45.897312       1 log.go:34] Export Sending batch of size: 121 MB.
I0119 20:17:56.490773       1 log.go:34] Export Time elapsed: 02h58m47s, bytes sent: 105 GiB, speed: 10 MiB/sec, jemalloc: 52 GiB
I0119 20:17:56.692415       1 log.go:34] Export Sending batch of size: 120 MB.
I0119 20:18:03.887674       1 log.go:34] Compaction backed off 195000 times
I0119 20:18:03.898254       1 log.go:34] Compaction backed off 195000 times
I0119 20:18:03.974935       1 log.go:34] Compaction backed off 195000 times

I have not seen messages starting with “Compacting backed off” and “Block cache metrics” before. Are these error messages?

The export finished successfully:

647G    ./p
2.4M    ./zw
4.0K    ./t
12G     ./export/dgraph.r640005.u0119.1719
12G     ./export
188M    ./w
2

Nope, errors are explicit. And in general, you should pay attention to panics. The other logs are good/rich information about the cluster and might help in investigations.

Also, you might see new types of logs in the future. Cuz it is a good practice to throw logs.