* [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>
