Symbol tables with fewer than 128 entries, so everything can be
represented as a single byte, are not realistic.
Stuff the symbol table with fake entries before adding the real ones.
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>
When the label name is empty, which can happen now with quoted label
name, it should be quoted when printed as a string again.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Converted string to standarized form
* Added golang.org/x/text in Go dependencies
* Added test cases for FastRegexMatcher
* Added benchmark for toNormalizedLower
Signed-off-by: RA <ranveeravhad777@gmail.com>
This replaces the custom `moreThanOneRune` function with the standard
`utf8.DecodeRuneInString(s)` that can be used to figure out the size of
the first rune.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
This adds some more test cases for unicode values, and also a benchmark
for zeroOrOneCharacterStringMatcher.Matches()
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
When the label name of a matcher contains non-standard characters, like
a dot, or starts with a digit, it should be quoted.
If it's not quoted, then `VectorSelector.String()` isn't a valid PromQL.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
When `zeroOrOneCharacterStringMatcher` wach checking the input string,
it assumed that if there are more than one bytes, then there are more
than one runes, but that's not necessarily true.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
The strings produced by these tests can run to thousands of characters,
which makes test logs difficult to read.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Restrict the capacity of first argument to `append()` to force an allocation.
This is for the slice implementation only.
Signed-off-by: Domantas Jadenkus <djadenkus@gmail.com>
I was bored on a train and I spent some amount of time trying to scratch
some nanoseconds off the Labels.Compare when running with stringlabels.
I would be ashamed to admit the real amount of time I spent on it.
The worst thing is, I can't really explain why this is performing so
much better, and someone should re-run the benchmarks on their machine
to confirm that it's not something related to general relativity because
the train is moving. I also added some extra real-life benchmark cases
with longer labelsets (these aren't the longest we have in production,
but kubernetes labelsets are fairly common in Prometheus so I thought it
would be nice to have them).
My benchmarks show this diff:
goos: darwin
goarch: arm64
pkg: github.com/prometheus/prometheus/model/labels
│ old │ new │
│ sec/op │ sec/op vs base │
Labels_Compare/equal 5.898n ± 0% 5.875n ± 1% -0.40% (p=0.037 n=10)
Labels_Compare/not_equal 11.78n ± 2% 11.01n ± 1% -6.54% (p=0.000 n=10)
Labels_Compare/different_sizes 4.959n ± 1% 4.906n ± 2% -1.05% (p=0.050 n=10)
Labels_Compare/lots 21.32n ± 0% 17.54n ± 5% -17.75% (p=0.000 n=10)
Labels_Compare/real_long_equal 15.06n ± 1% 14.92n ± 0% -0.93% (p=0.000 n=10)
Labels_Compare/real_long_different_end 25.20n ± 0% 24.43n ± 0% -3.04% (p=0.000 n=10)
geomean 11.86n 11.25n -5.16%
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
Use a stack buffer to reduce memory allocations.
`Write(AppendQuote(AvailableBuffer` does not allocate or copy when
the buffer has sufficient space.
Also add a benchmark, with some refactoring.
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>
The current implementation of `InternStrings` will only save memory
when the whole set of labels is identical to one already seen, and this
cannot happen in the one place it is called from in Prometheus,
remote-write, which already detects identical series.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This PR is a reference implementation of the proposal described in #10420.
In addition to what described in #10420, in this PR I've introduced labels.StableHash(). The idea is to offer an hashing function which doesn't change over time, and that's used by query sharding in order to get a stable behaviour over time. The implementation of labels.StableHash() is the hashing function used by Prometheus before stringlabels, and what's used by Grafana Mimir for query sharding (because built before stringlabels was a thing).
Follow up work
As mentioned in #10420, if this PR is accepted I'm also open to upload another foundamental piece used by Grafana Mimir query sharding to accelerate the query execution: an optional, configurable and fast in-memory cache for the series hashes.
Signed-off-by: Marco Pracucci <marco@pracucci.com>
This function is called very frequently when executing PromQL functions,
and we can do it much more efficiently inside Labels.
In the common case that `__name__` comes first in the labels, we simply
re-point to start at the next label, which is nearly free.
`DropMetricName` is now so cheap I removed the cache - benchmarks show
everything still goes faster.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This reduces bulk and should avoid issues if a fix is made in one file
and not the other.
A few methods now call `Range()` instead of `range`, but nothing
performance-sensitive.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Labels: reduce allocations when creating from TSDB
When reading the WAL, by passing references into the buffer we can avoid
copying strings under `-tags stringlabels`.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
