prometheus

The Prometheus monitoring system and time series database.

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Tree: ffb0ec2ca4

Bryan Boreham d166da7b59 tsdb: stop saving a copy of last 4 samples in memSeries (#11296 ) * TSDB chunks: remove race between writing and reading Because the data is stored as a bit-stream, the last byte in the stream could change if the stream is appended to after an Iterator is obtained. Copy the last byte when the Iterator is created, so we don't have to read it later. Clarify in comments that concurrent Iterator and Appender are allowed, but the chunk must not be modified while an Iterator is created. (This was already the case, in order to copy the bstream slice header.) * TSDB: stop saving last 4 samples in memSeries This extra copy of the last 4 samples was introduced to avoid a race condition between reading the last byte of the chunk and writing to it. But now we have fixed that by having `bstreamReader` copy the last byte, we don't need to copy the last 4 samples. This change saves 56 bytes per series, which is very worthwhile when you have millions or tens of millions of series. * TSDB: tidy up stopIterator re-use Previous changes have left this code duplicating some lines; pull them out to a separate function and tidy up. * TSDB head_test: stop checking when iterators are wrapped The behaviour has changed so chunk iterators are only wrapped when transaction isolation requires them to stop short of the end. This makes tests fail which are checking the type. Tests should check the observable behaviour, not the type. Signed-off-by: Bryan Boreham <bjboreham@gmail.com> Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com> Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>		2 years ago
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bstream.go	tsdb: stop saving a copy of last 4 samples in memSeries (#11296 )	2 years ago
bstream_test.go	…
chunk.go	Add out-of-order sample support to the TSDB (#11075 )	2 years ago
chunk_test.go	Reduce memory allocation in benchmarkIterator() (#5983 )	3 years ago
xor.go	tsdb: stop saving a copy of last 4 samples in memSeries (#11296 )	2 years ago