This is another corner-case that was previously never exercised
because the rewriting of a series file was never prevented by the
shrink ratio.
Scenario: There is an existing series on disk, which is archived. If a
new sample comes in for that file, a new chunk in memory is created,
and the chunkDescsOffset is set to -1. If series maintenance happens
before the series has at least one chunk to persist _and_ an
insufficient chunks on disk is old enough for purging (so that the
shrink ratio kicks in), dropAndPersistChunks would return 0, but it
should return the chunk length of the series file.
Also, in that code path, set chunkDescsOffset to 0 rather than -1 in
case of "dropped more chunks from persistence than from memory" so
that no other weird things happen before the series is quarantined for
good.
The fuzzy library didn't try to find a "best match", but settled on the
first fuzzy match that exists. This patch includes a modified version of
the fuzzy library, which recursivley tries on the rest of the search
string to find a better match. If found, returns that one.
Another small modification is that if a pattern fully matches, it
skips the lookup entirley and returns the highest score possible for
that match.
For some of the queries, the fuzzy lookup was not filtering properly.
The problem is due to the "replace" beind made on the query itself. It
accidently removes only the first underscore. This patch changes it so
that it removes all of the whitespaces, letting the fuzzy algorithm do
its magic, also fixing this problem.
Originally, the underscore were replaced by a space for this specific
reason, to let the user type a space and have the lookup treat it as the
word break.
Fixes#2380
The append call may reuse cds, and thus change its len.
(In practice, this wouldn't happen as cds should have len==cap.
Still, the previous order of lines was problematic.)
This is an initial (and hacky) first pass on allowing
appending to multiple blocks simultaniously to avoid
dropping samples right after cutting a new head block.
It's also required for cases like the PGW, where a scrape may
contain varying timestamps.
