Flushing buffers and doing a pwrite per posting is expensive
time wise, so go back to the old way for those. This doubles
our memory usage, but that's still small as it's only
~8 bytes per time series in the index. This is 30-40% faster.
benchmark old ns/op new ns/op delta
BenchmarkCompactionFromHead/labelnames=1,labelvalues=100000-4 1101429174 724362123 -34.23%
BenchmarkCompactionFromHead/labelnames=10,labelvalues=10000-4 1074466374 720977022 -32.90%
BenchmarkCompactionFromHead/labelnames=100,labelvalues=1000-4 1166510282 677702636 -41.90%
BenchmarkCompactionFromHead/labelnames=1000,labelvalues=100-4 1075013071 696855960 -35.18%
BenchmarkCompactionFromHead/labelnames=10000,labelvalues=10-4 1231673790 829328610 -32.67%
benchmark old allocs new allocs delta
BenchmarkCompactionFromHead/labelnames=1,labelvalues=100000-4 832571 731435 -12.15%
BenchmarkCompactionFromHead/labelnames=10,labelvalues=10000-4 894875 793823 -11.29%
BenchmarkCompactionFromHead/labelnames=100,labelvalues=1000-4 912931 811804 -11.08%
BenchmarkCompactionFromHead/labelnames=1000,labelvalues=100-4 933511 832366 -10.83%
BenchmarkCompactionFromHead/labelnames=10000,labelvalues=10-4 1022791 921554 -9.90%
benchmark old bytes new bytes delta
BenchmarkCompactionFromHead/labelnames=1,labelvalues=100000-4 129063496 126472364 -2.01%
BenchmarkCompactionFromHead/labelnames=10,labelvalues=10000-4 124154888 122300764 -1.49%
BenchmarkCompactionFromHead/labelnames=100,labelvalues=1000-4 128790648 126394856 -1.86%
BenchmarkCompactionFromHead/labelnames=1000,labelvalues=100-4 120570696 118946548 -1.35%
BenchmarkCompactionFromHead/labelnames=10000,labelvalues=10-4 138754288 136317432 -1.76%
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
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