Commit Graph

11 Commits (a59b7ac7f863e2fdb1b05596f94a8889abeeb815)

Author SHA1 Message Date
beorn7 ff08f0b6fe storage: ensure timestamp monotonicity within series.
Fixes https://github.com/prometheus/prometheus/issues/481

While doing so, clean up and fix a few other things:

- Fix `go vet` warnings (@fabxc to blame ;).

- Fix a racey problem with unarchiving: Whenever we unarchive a
  series, we essentially want to do something with it. However, until
  we have done something with it, it appears like a series that is
  ready to be archived or even purged. So e.g. it would be ignored
  during checkpointing. With this fix, we always load the chunkDescs
  upon unarchiving. This is wasteful if we only want to add a new
  sample to an archived time series, but the (presumably more common)
  case where we access an archived time series in a query doesn't
  become more expensive.

- The change above streamlined the getOrCreateSeries ond
  newMemorySeries flow. Also, the modTime is now always set correctly.

- Fix the leveldb-backed implementation of KeyValueStore.Delete. It
  had the wrong behavior of still returning true, nil if a
  non-existing key has been passed in.
2015-07-15 18:56:53 +02:00
Julius Volz acbc2b8cb6 storage: Fix float->uint conversions on some compilers.
See https://github.com/prometheus/prometheus/issues/887, which will at
least be partially fixed by this.

From the spec https://golang.org/ref/spec#Conversions:

"In all non-constant conversions involving floating-point or complex
values, if the result type cannot represent the value the conversion
succeeds but the result value is implementation-dependent."

This ended up setting the converted values to 0 on Debian's Go 1.4.2
compiler, at least on 32-bit Debians.
2015-07-13 11:19:11 +02:00
beorn7 3b9c421a69 Weed out all the [Gg]et* method names.
The only exception is getNumChunksToPersist to avoid naming the struct
member numChunksToPersist in a weird way.
2015-05-20 19:13:06 +02:00
beorn7 81b190bf45 Remove locking from series iterator. Cache chunk iterators. 2015-05-20 16:19:34 +02:00
beorn7 cd5574bf8a Make chunk and series iterators more efficient. 2015-05-20 16:19:34 +02:00
beorn7 b02d900e61 Improve chunk and chunkDesc loading.
Also, clean up some things in the code (especially introduction of the
chunkLenWithHeader constant to avoid the same expression all over the place).

Benchmark results:

BEFORE
BenchmarkLoadChunksSequentially     5000            283580 ns/op          152143 B/op        312 allocs/op
BenchmarkLoadChunksRandomly        20000             82936 ns/op           39310 B/op         99 allocs/op
BenchmarkLoadChunkDescs            10000            110833 ns/op           15092 B/op        345 allocs/op

AFTER
BenchmarkLoadChunksSequentially    10000            146785 ns/op          152285 B/op        315 allocs/op
BenchmarkLoadChunksRandomly        20000             67598 ns/op           39438 B/op        103 allocs/op
BenchmarkLoadChunkDescs            20000             99631 ns/op           12636 B/op        192 allocs/op

Note that everything is obviously loaded from the page cache (as the
benchmark runs thousands of times with very small series files). In a
real-world scenario, I expect a larger impact, as the disk operations
will more often actually hit the disk. To load ~50 sequential chunks,
this reduces the iops from 100 seeks and 100 reads to 1 seek and 1
read.
2015-04-13 21:06:04 +02:00
beorn7 5bea942d8e Improve various things around chunk encoding.
A number of mostly minor things:

- Rename chunk type -> chunk encoding.

- After all, do not carry around the chunk encoding to all parts of
  the system, but just have one place where the encoding for new
  chunks is set based on the flag. The new approach has caveats as
  well, but the polution of so many method signatures is worse.

- Use the default chunk encoding for new chunks of existing
  series. (Previously, only new _series_ would get chunks with the
  default encoding.)

- Use an enum for chunk encoding. (But keep the version number for the
  flag, for reasons discussed previously.)

- Add encoding() to the chunk interface (so that a chunk knows its own
  encoding - no need to have that in a different top-level function).

- Got rid of newFollowUpChunk (which would keep the existing encoding
  for all chunks of a time series). Now only use newChunk(), which
  will create a chunk encoding according to the flag.

- Simplified transcodeAndAdd.

- Reordered methods of deltaEncodedChunk and doubleDeltaEncoded chunk
  to match the order in the chunk interface.

- Only transcode if the chunk is not yet half full. If more than half
  full, add a new chunk instead.
2015-03-14 19:03:20 +01:00
beorn7 853f971540 Actually use double-delta encoding for transcoding. :-o 2015-03-11 16:52:58 +01:00
beorn7 23ba8a5516 Make floats exact again.
This should do the right thing for the old delta chunks, too.
2015-03-06 17:03:56 +01:00
beorn7 a8d4f8af9a Improve minor things after review.
The problem of float precision will be addressed in the next commit.
2015-03-06 12:53:00 +01:00
beorn7 13fcf1ddbc Implement double-delta encoded chunks. 2015-03-05 20:33:26 +01:00