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Improve tracing

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Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
This commit is contained in:
Arve Knudsen 2023-10-30 14:30:12 +01:00
parent 25e2c05a47
commit 2aabf7cc2c
1 changed files with 8 additions and 13 deletions
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21
tsdb/postings_for_matchers_cache.go
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@ -77,12 +77,7 @@ type PostingsForMatchersCache struct {
}
func (c *PostingsForMatchersCache) PostingsForMatchers(ctx context.Context, ix IndexPostingsReader, concurrent bool, ms ...*labels.Matcher) (index.Postings, error) {
var matcherStrs []string
for _, m := range ms {
matcherStrs = append(matcherStrs, m.String())
}
ctx, span := otel.Tracer("").Start(ctx, "PostingsForMatchersCache.PostingsForMatchers", trace.WithAttributes(
attribute.StringSlice("matchers", matcherStrs),
attribute.Bool("concurrent", concurrent),
attribute.Bool("force", c.force),
))
@ -94,6 +89,8 @@ func (c *PostingsForMatchersCache) PostingsForMatchers(ctx context.Context, ix I
span.RecordError(err)
return p, err
}
span.AddEvent("using cache")
c.expire()
p, err := c.postingsForMatchersPromise(ctx, ix, ms)(ctx)
span.RecordError(err)
@ -138,26 +135,24 @@ func (p *postingsForMatcherPromise) result(ctx context.Context) (index.Postings,
}
func (c *PostingsForMatchersCache) postingsForMatchersPromise(ctx context.Context, ix IndexPostingsReader, ms []*labels.Matcher) func(context.Context) (index.Postings, error) {
ctx, span := otel.Tracer("").Start(ctx, "PostingsForMatchersCache.postingsForMatchersPromise")
key := matchersKey(ms)
ctx, span := otel.Tracer("").Start(ctx, "PostingsForMatchersCache.postingsForMatchersPromise", trace.WithAttributes(
attribute.String("cache_key", key),
))
defer span.End()
promise := new(postingsForMatcherPromise)
promise.done = make(chan struct{})
key := matchersKey(ms)
oldPromise, loaded := c.calls.LoadOrStore(key, promise)
if loaded {
// promise was not stored, we return a previously stored promise, that's possibly being fulfilled in another goroutine
span.AddEvent("using cached postingsForMatchers promise", trace.WithAttributes(
attribute.String("key", key),
))
span.AddEvent("using cached postingsForMatchers promise")
close(promise.done)
return oldPromise.(*postingsForMatcherPromise).result
}
span.AddEvent("no postingsForMatchers promise in cache, executing query", trace.WithAttributes(
attribute.String("key", key)),
)
span.AddEvent("no postingsForMatchers promise in cache, executing query")
// promise was stored, close its channel after fulfilment
defer close(promise.done)