This commit adds a tsm1 function for encoding a batch of floats into a
buffer. Further, it replaces the `bitstream` library used in the
existing encoders (and all the current decoders) with inlined bit
expressions within the encoder, significantly reducing the function call
overhead for larger batches.
The following benchmarks compare the performance of the existing
iterator based encoders, and the new batch oriented encoders. They look
at a sequential input slice and a randomly generated input slice.
name old time/op new time/op delta
EncodeFloats/10_seq 1.14µs ± 3% 0.24µs ± 3% -78.94% (p=0.000 n=10+10)
EncodeFloats/10_ran 1.69µs ± 2% 0.21µs ± 3% -87.43% (p=0.000 n=10+10)
EncodeFloats/100_seq 7.07µs ± 1% 1.72µs ± 1% -75.62% (p=0.000 n=7+9)
EncodeFloats/100_ran 15.8µs ± 4% 1.8µs ± 1% -88.60% (p=0.000 n=10+9)
EncodeFloats/1000_seq 50.2µs ± 3% 16.2µs ± 2% -67.66% (p=0.000 n=10+10)
EncodeFloats/1000_ran 174µs ± 2% 16µs ± 2% -90.77% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
EncodeFloats/10_seq 0.00B 0.00B ~ (all equal)
EncodeFloats/10_ran 0.00B 0.00B ~ (all equal)
EncodeFloats/100_seq 0.00B 0.00B ~ (all equal)
EncodeFloats/100_ran 0.00B 0.00B ~ (all equal)
EncodeFloats/1000_seq 0.00B 0.00B ~ (all equal)
EncodeFloats/1000_ran 0.00B 0.00B ~ (all equal)
name old allocs/op new allocs/op delta
EncodeFloats/10_seq 0.00 0.00 ~ (all equal)
EncodeFloats/10_ran 0.00 0.00 ~ (all equal)
EncodeFloats/100_seq 0.00 0.00 ~ (all equal)
EncodeFloats/100_ran 0.00 0.00 ~ (all equal)
EncodeFloats/1000_seq 0.00 0.00 ~ (all equal)
EncodeFloats/1000_ran 0.00 0.00 ~ (all equal)
This commit makes a number of performance improvements to
reduce allocations during query execution. Several objects
and buffers are now reused across the components to avoid
allocations.
Previously a simple `count(value)` query across 1M points
would require 26,000+ allocations. After the changes in
this commit that number has been reduced to 88.
The current go compiler at the tip of the go master (1d5001af) has a modified implementation of
testing.quick.Check that now generates nil slices as test data. (See: https://gophers.slack.com/archives/general/p14567053570110). The existing tests expect round tripping to work in this case
but it does not. So, in these cases we change the expectation to reflect actual behaviour.
This needs to be checked for reasonableness.
If similar float values were encoded, the number of leading bits would
overflow the 5 available bits to store them (e.g. store 33 in 5 bits). When
decoding, the values after the overflowed value would spike to very large and
small values.
To prevent the overflow, we clamp the value to 31 which is the maximum
number of leading zero bits we can encoded.
Fixes#4357
Will make it less error-prone to add new encodings int the future
since each encoder has it's set of constants. There are some placeholder
contants for uncompressed encodings which are not in all encoder currently.
Edd Robinson
Stuart Carnie
Jason Wilder
Mark Rushakoff
Ben Johnson
Jon Seymour
Paul Dix