When a large Prometheus starts up fresh it can take many minutes
to warmup and clear out the index queue. A larger queue means less
blocking, bigger batches and cuts down startup time by ~50%.
This adds a position mapper that takes series from a head block
in the order they were appended and creates a mapping representing
them in order of their label sets.
Write-repair of the postings list would cause very expensive writing.
Hence, we keep them as they are and only apply the postition mapping
at the very end, after a postings list has been sufficienctly reduced
through intersections etc.
This initializes the chunkDesc's last timestamp to the minimum
value so initial samples with a timestamp of 0 (e.g. in tests)
are not accidentally dropped.
The relative links don't work in other pages that render the README (for example https://hub.docker.com/r/prom/prometheus/). As they are (hopefully) not due to change any time soon, I think using absolute links is better.
This adds a basic compactor that will merge two persisted blocks into
one. It simply fully rewrites the index and concatenates the chunk
lists.
It just writes into the current working dir and doesn't properly handle
which blocks to compact for now.
This changes the IndexReader API to expose plain labels
and chunk meta information instead of a Series interface.
Dropping of irrelevant chunks is moved into the querier.
A LabelIndices method is added to query for existing label
value indices.
Right now the /alerts page of Prometheus sorts alerts by severity
(firing, pending, inactive). Once multiple alerts have the same
severity, their order seems to correlate to how they are placed in the
configuration files, but not always. Looking at the code, we make use of
sort.Sort(), which is documented not to provide a stable sort. The
Less() function also only takes the alert state into account.
This change extends the Less() function to provide a lexicographic order
on both the alert state and the name. This means I can finally find the
alerts I'm looking for without using my browser's search feature.