The reducers already had a local RNG but mistakenly did not use it when
sampling points.
Because the local RNG is not protected by a mutex, there is a slight
speedup as a result of this change:
benchmark old ns/op new ns/op delta
BenchmarkSampleIterator_1k-4 418 418 +0.00%
BenchmarkSampleIterator_100k-4 434 422 -2.76%
BenchmarkSampleIterator_1M-4 449 439 -2.23%
benchmark old allocs new allocs delta
BenchmarkSampleIterator_1k-4 3 3 +0.00%
BenchmarkSampleIterator_100k-4 3 3 +0.00%
BenchmarkSampleIterator_1M-4 3 3 +0.00%
benchmark old bytes new bytes delta
BenchmarkSampleIterator_1k-4 304 304 +0.00%
BenchmarkSampleIterator_100k-4 304 304 +0.00%
BenchmarkSampleIterator_1M-4 304 304 +0.00%
The speedup would presumably increase when multiple sample iterators are
used concurrently.
First Pass at implementing sample
Add sample iterators for all types
Remove size from sample struct
Fix off by one error when generating random number
Add benchmarks for sample iterator
Add test and associated fixes for off by one error
Add test for sample function
Remove NumericLiteral from sample function call
Make clear that the counter is incr w/ each call
Rename IsRandom to AllSamplesSeen
Add a rng for each reducer that is created
The default rng that comes with math/rand has a global lock. To avoid
having to worry about any contention on the lock, each reducer now has
its own time seeded rng.
Add sample function to changelog
This change moves tracking of next timestamp and values to simple
slices, as performance measurement showed that Peek() on TagSet cursors
was a huge performance drain. There is much more that can be done here,
but with this in place query performance has been restored to 0.9.1
levels.
This change also uses -1 to indicate that no value is available for a
given timestamp.
If the MapMean did not have any values in the iterator, it would return
and empty meanMapOutput(). ReduceMean would in turn divider the results
by an unitialized float64 producing a NaN. NaN is not serializable to JSON
by default.
Mark Rushakoff
Michael Desa
Nathaniel Cook
Daniel Morsing
Cory LaNou
Philip O'Toole
Philip O'Toole
Ben Johnson
Levi Cook
Jason Wilder
ben hockey