When using queries like 'select count(_seriesKey) from bigmeasurement`, we
should iterate over the tsi structures to serve the query instead of loading
all the series into memory up front.
Closes#20543
Since all tag sets are materialised to strings before this method
returns, a large number of allocations can be avoided by carefully
resuing buffers and containers.
This commit reduces allocations by about 75%, which can be very
significant for high cardinality workloads.
The benchmark results shown below are for a benchmark that asks for all
series keys matching `tag5=value0'.
name old time/op new time/op delta
Index_ConcurrentWriteQuery/inmem/queries_100000-8 5.66s ± 4% 5.70s ± 5% ~ (p=0.739 n=10+10)
Index_ConcurrentWriteQuery/tsi1/queries_100000-8 26.5s ± 8% 26.8s ±12% ~ (p=0.579 n=10+10)
IndexSet_TagSets/1M_series/inmem-8 11.9ms ±18% 10.4ms ± 2% -12.81% (p=0.000 n=10+10)
IndexSet_TagSets/1M_series/tsi1-8 23.4ms ± 5% 18.9ms ± 1% -19.07% (p=0.000 n=10+9)
name old alloc/op new alloc/op delta
Index_ConcurrentWriteQuery/inmem/queries_100000-8 2.50GB ± 0% 2.50GB ± 0% ~ (p=0.315 n=10+10)
Index_ConcurrentWriteQuery/tsi1/queries_100000-8 32.6GB ± 0% 32.6GB ± 0% ~ (p=0.247 n=10+10)
IndexSet_TagSets/1M_series/inmem-8 3.56MB ± 0% 3.56MB ± 0% ~ (all equal)
IndexSet_TagSets/1M_series/tsi1-8 12.7MB ± 0% 5.2MB ± 0% -59.02% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
Index_ConcurrentWriteQuery/inmem/queries_100000-8 24.0M ± 0% 24.0M ± 0% ~ (p=0.353 n=10+10)
Index_ConcurrentWriteQuery/tsi1/queries_100000-8 96.6M ± 0% 96.7M ± 0% ~ (p=0.579 n=10+10)
IndexSet_TagSets/1M_series/inmem-8 51.0 ± 0% 51.0 ± 0% ~ (all equal)
IndexSet_TagSets/1M_series/tsi1-8 80.4k ± 0% 20.4k ± 0% -74.65% (p=0.000 n=10+10)
Since partitions slice is not protected under a lock, setting it to
nil while closing causes a race if concurrent calls are accessing
the partitions slice elsewhere. Since partitions do handle
concurrency and Open resets the slice, just leave it as it after
closing.
The series file compaction previously did not snapshot the max
offset before compacting and would keep compacting until it reached
the end of segment file. This caused more entries than expected into
the RHH map and this map gets exponentially slower as it gets close
to full.
This commit ensures that the series file should work appropriately on
32-bit architecturs. It does this by reducing the maximum size of a
series file to 512MB on 32-bit systems, which should be fully
addressable.
It further updates tests so that the series file size can be reduced
further when running many tests in parallel on 32-bit architectures.
Sam Arnold
Edd Robinson
Jacob Marble
Grzegorz Pomykala
Ben Johnson
Jason Wilder