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13 commits

Author SHA1 Message Date
Julius Volz e8d963d630 Remove some dead code.
Change-Id: Ie148b506eb6037a0f44d976a2b53e4bf7e64e212
2014-02-27 19:48:55 +01:00
Julius Volz 740d448983 Use custom timestamp type for sample timestamps and related code.
So far we've been using Go's native time.Time for anything related to sample
timestamps. Since the range of time.Time is much bigger than what we need, this
has created two problems:

- there could be time.Time values which were out of the range/precision of the
  time type that we persist to disk, therefore causing incorrectly ordered keys.
  One bug caused by this was:

  https://github.com/prometheus/prometheus/issues/367

  It would be good to use a timestamp type that's more closely aligned with
  what the underlying storage supports.

- sizeof(time.Time) is 192, while Prometheus should be ok with a single 64-bit
  Unix timestamp (possibly even a 32-bit one). Since we store samples in large
  numbers, this seriously affects memory usage. Furthermore, copying/working
  with the data will be faster if it's smaller.

*MEMORY USAGE RESULTS*
Initial memory usage comparisons for a running Prometheus with 1 timeseries and
100,000 samples show roughly a 13% decrease in total (VIRT) memory usage. In my
tests, this advantage for some reason decreased a bit the more samples the
timeseries had (to 5-7% for millions of samples). This I can't fully explain,
but perhaps garbage collection issues were involved.

*WHEN TO USE THE NEW TIMESTAMP TYPE*
The new clientmodel.Timestamp type should be used whenever time
calculations are either directly or indirectly related to sample
timestamps.

For example:
- the timestamp of a sample itself
- all kinds of watermarks
- anything that may become or is compared to a sample timestamp (like the timestamp
  passed into Target.Scrape()).

When to still use time.Time:
- for measuring durations/times not related to sample timestamps, like duration
  telemetry exporting, timers that indicate how frequently to execute some
  action, etc.

*NOTE ON OPERATOR OPTIMIZATION TESTS*
We don't use operator optimization code anymore, but it still lives in
the code as dead code. It still has tests, but I couldn't get all of them to
pass with the new timestamp format. I commented out the failing cases for now,
but we should probably remove the dead code soon. I just didn't want to do that
in the same change as this.

Change-Id: I821787414b0debe85c9fffaeb57abd453727af0f
2013-12-03 09:11:28 +01:00
Matt T. Proud 8f4c7ece92 Destroy naked returns in half of corpus.
The use of naked return values is frowned upon.  This is the first
of two bulk updates to remove them.
2013-05-16 10:53:25 +03:00
Matt T. Proud 4e0c932a4f Simplify Encoder's encoding signature.
The reality is that if we ever try to encode a Protocol Buffer and it
fails, it's likely that such an error is ultimately not a runtime error
and should be fixed forthwith.  Thusly, we should rename
``Encoder.Encode`` to ``Encoder.MustEncode`` and drop the error return
value.
2013-05-16 00:54:18 +03:00
Matt T. Proud e86f4d9dfd Convert time readers to represent time in UTC.
Go's time.Time represents time as UTC in its fundamental data type.
That said, when using ``time.Unix(...)``, it sets the zone for the
time representation to the local.  Unfortunately with diagnosis and
our tests, it is a PITA to jump between various zones, even though
the serialized version remains the same.

To keep things easy, all places where times are generated or read
are converted into UTC.  These conversions are cheap, for
``Time.In`` merely changes a pointer reference in the struct,
nothing more.  This enables me to diagnose test failures with fixture
data very easily.
2013-04-24 12:19:41 +02:00
Matt T. Proud c3e3460ca6 Spin up curator run in the tests.
After this commit, we'll need to add validations that it does the
desired work, which we presently know that it doesn't.  Given the
changes I made with a plethora of renamings, I want to commit this
now before it gets even larger.
2013-04-05 13:55:11 +02:00
Matt T. Proud f39b9c3c8e Checkpoint. 2013-03-21 18:06:51 +01:00
Matt T. Proud 13ae29b304 Initial in-memory arena implementation.
It is unbounded, and nothing uses it except for a gating flag in main.
2013-02-18 09:38:14 -06:00
Julius Volz d67e4b9131 Address outstanding comments from PR/47 and other cleanups. 2013-02-07 11:38:01 +01:00
Matt T. Proud 44f8802ae7 Add Apache License 2.0 boilerplate. 2012-11-26 20:11:34 +01:00
Matt T. Proud 2bbdaa5790 Initial directory re-arrangement for storage. 2012-11-26 19:56:51 +01:00
Matt T. Proud 720442d3d3 Use index singleton and relocate encoder package. 2012-11-25 16:07:05 +01:00
Matt T. Proud 6072143505 Initial commit of external resources. 2012-11-24 12:33:34 +01:00