* fix: Fix slicelabels corruption when used with proto decoding
Alternative to https://github.com/prometheus/prometheus/pull/16957/
Signed-off-by: bwplotka <bwplotka@gmail.com>
* addressed comments
Signed-off-by: bwplotka <bwplotka@gmail.com>
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Signed-off-by: bwplotka <bwplotka@gmail.com>
Add `ByteSize()` method to different labels implementations.
One of the use case so that we can track the memory used by Labels.
Signed-off-by: Jon Kartago Lamida <me@lamida.net>
Instead of using varint to encode the size of each label, use a single
byte for size 0-254, or a flag value of 255 followed by the size in
3 bytes little-endian.
This reduces the amount of code, and also the number of branches in
commonly-executed code, so it runs faster.
The maximum allowed label name or value length is now 2^24 or 16MB.
Memory used by labels changes as follows:
* Labels from 0 to 127 bytes length: same
* From 128 to 254: 1 byte less
* From 255 to 16383: 2 bytes more
* From 16384 to 2MB: 1 byte more
* From 2MB to 16MB: same
Labels: panic on string too long.
Slightly more user-friendly than encoding bad data and finding out when
we decode.
Clarify that Labels.Bytes() encoding can change
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Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* [ENHANCEMENT] TSDB: Improve calculation of space used by labels
The labels for each series in the Head take up some some space in the
Postings index, but far more space in the `memSeries` structure.
Instead of having the Postings index calculate this overhead, which is
a layering violation, have the caller pass in a function to do it.
Provide three implementations of this function for the three Labels
versions.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Since `seps` is a variable, `seps[0]` has to be bounds-checked every
time. Replacing with a constant everywhere it is used skips this
overhead.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Inline (by copy-paste) the fast path of `decodeVarint` in various
places where it gets called a lot.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
The individual strings for label names and values are held in a table,
and each Labels value is a run of varint-encoded indexes into that table.
When creating new labels, a sync.Mutex is locked around reads and writes.
When reading labels, there is no locking because the table of strings
used by those labels is immutable.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
