github/prometheus - prometheus - https://git.xinac.net

Author	SHA1	Message	Date
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.	10 years ago
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.	10 years ago
beorn7	853f971540	Actually use double-delta encoding for transcoding. :-o	10 years ago
beorn7	23ba8a5516	Make floats exact again. This should do the right thing for the old delta chunks, too.	10 years ago
beorn7	a8d4f8af9a	Improve minor things after review. The problem of float precision will be addressed in the next commit.	10 years ago
beorn7	13fcf1ddbc	Implement double-delta encoded chunks.	10 years ago