An design question was open for me in the beginning was whether to
serialize other types to disk, but Protocol Buffers quickly won out,
which allows us to drop support for other types. This is a good
start to cleaning up a lot of cruft in the storage stack and
can let us eventually decouple the various moving parts into
separate subsystems for easier reasoning.
This commit is not strictly required, but it is a start to making
the rest a lot more enjoyable to interact with.
This adds timers around several query-relevant code blocks. For now, the
query timer stats are only logged for queries initiated through the UI.
In other cases (rule evaluations), the stats are simply thrown away.
My hope is that this helps us understand where queries spend time,
especially in cases where they sometimes hang for unusual amounts of
time.
In order to help corroborate whether a Prometheus instance has
flapped until meta-monitoring is in-place, we ought to provide the
instance's start time in the console to aid in diagnostics.
This commit simplifies the way that compactions across a database's
keyspace occur due to reading the LevelDB internals. Secondarily it
introduces the database size estimation mechanisms.
Include database health and help interfaces.
Add database statistics; remove status goroutines.
This commit kills the use of Go routines to expose status throughout
the web components of Prometheus. It also dumps raw LevelDB status
on a separate /databases endpoint.
This commit introduces three background compactors, which compact
sparse samples together.
1. Older than five minutes is grouped together into chunks of 50 every 30
minutes.
2. Older than 60 minutes is grouped together into chunks of 250 every 50
minutes.
3. Older than one day is grouped together into chunks of 5000 every 70
minutes.
Unfortunately ``cp`` on Darwin regards some flags as positional and
requires them to be in a specific place. The new Protocol Buffer
descriptor bundling fails on Mac OS.
