Improve Structural Operators Perf

[joe-elliott]

What this PR does:
The PR improves performance by using a standard sort/search procedure but that requires having both the LHS and RHS of the operator at the fetch layer (where it is aware of nested set implementation details). The cost is a very ungainly change to the span interface:

	SiblingOf([]Span, []Span, bool, bool, []Span) []Span
	DescendantOf([]Span, []Span, bool, bool, []Span) []Span
	ChildOf([]Span, []Span, bool, bool, []Span) []Span

These methods no longer operate on the span itself which is strange. However, there is no other clean places to place it that can be easily accessed deep in the engine where the evaluations occur.

Other fixes:

• Fixed an issue where {} !~ {} would not find the root span. The way the fix is implemented multiple root spans will be considered siblings using a query like {} ~ {}
• Fixed the bridge iterator sort to use the correct definition level

Benchmarks to follow.

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[joe-elliott]

Benchmarks show significant improvements on the worst case and even performance in the normal case.

Queries

{"sibling", "{ resource.service.name = `loki-querier` } ~ { resource.service.name = `loki-querier` }"},
{"desc", "{ resource.service.name = `loki-querier` } >> { resource.service.name = `loki-querier` }"},
{"child", "{ resource.service.name = `loki-querier` } > { resource.service.name = `loki-querier` }"},

name                           old time/op    new time/op    delta
BackendBlockTraceQL/sibling-8     956ms ± 6%     841ms ± 2%  -12.05%  (p=0.008 n=5+5)
BackendBlockTraceQL/desc-8        1.04s ± 7%     1.08s ±12%     ~     (p=0.548 n=5+5)
BackendBlockTraceQL/child-8       1.06s ± 8%     1.12s ±10%     ~     (p=0.222 n=5+5)

name                           old speed      new speed      delta
BackendBlockTraceQL/sibling-8  14.9MB/s ± 6%  16.9MB/s ± 2%  +13.56%  (p=0.008 n=5+5)
BackendBlockTraceQL/desc-8     15.1MB/s ± 6%  14.6MB/s ±11%     ~     (p=0.548 n=5+5)
BackendBlockTraceQL/child-8    14.9MB/s ± 7%  14.1MB/s ±10%     ~     (p=0.222 n=5+5)

name                           old MB_io/op   new MB_io/op   delta
BackendBlockTraceQL/sibling-8      14.2 ± 0%      14.2 ± 0%     ~     (all equal)
BackendBlockTraceQL/desc-8         15.7 ± 0%      15.7 ± 0%     ~     (all equal)
BackendBlockTraceQL/child-8        15.7 ± 0%      15.7 ± 0%     ~     (all equal)

name                           old alloc/op   new alloc/op   delta
BackendBlockTraceQL/sibling-8    50.4MB ± 3%    48.0MB ±14%     ~     (p=0.286 n=4+5)
BackendBlockTraceQL/desc-8       44.5MB ± 5%    50.8MB ±18%  +14.18%  (p=0.016 n=5+5)
BackendBlockTraceQL/child-8      46.3MB ± 8%    43.8MB ± 0%     ~     (p=0.690 n=5+5)

name                           old allocs/op  new allocs/op  delta
BackendBlockTraceQL/sibling-8      109k ± 3%      109k ± 4%     ~     (p=0.905 n=4+5)
BackendBlockTraceQL/desc-8         107k ± 0%      111k ± 6%   +3.95%  (p=0.008 n=5+5)
BackendBlockTraceQL/child-8        106k ± 0%      107k ± 0%   +0.83%  (p=0.008 n=5+5)

Queries

{"sibling", "{ resource.service.name = `loki-querier` } ~ { name != `` }"},
{"desc", "{ resource.service.name = `loki-querier` } >> { name != `` }"},
{"child", "{ resource.service.name = `loki-querier` } > { name != `` }"},

name                           old time/op    new time/op     delta
BackendBlockTraceQL/sibling-8     1.82s ± 7%      1.48s ±16%  -18.61%  (p=0.016 n=5+5)
BackendBlockTraceQL/desc-8        1.84s ± 3%      1.68s ± 6%   -9.08%  (p=0.008 n=5+5)
BackendBlockTraceQL/child-8       1.88s ± 4%      1.58s ± 5%  -15.88%  (p=0.008 n=5+5)

name                           old speed      new speed       delta
BackendBlockTraceQL/sibling-8  8.47MB/s ± 7%  10.45MB/s ±15%  +23.35%  (p=0.016 n=5+5)
BackendBlockTraceQL/desc-8     12.2MB/s ± 3%   13.4MB/s ± 6%  +10.06%  (p=0.008 n=5+5)
BackendBlockTraceQL/child-8    11.9MB/s ± 4%   14.2MB/s ± 4%  +18.86%  (p=0.008 n=5+5)

name                           old MB_io/op   new MB_io/op    delta
BackendBlockTraceQL/sibling-8      15.4 ± 0%       15.4 ± 0%     ~     (all equal)
BackendBlockTraceQL/desc-8         22.4 ± 0%       22.4 ± 0%     ~     (all equal)
BackendBlockTraceQL/child-8        22.5 ± 0%       22.5 ± 0%     ~     (all equal)

name                           old alloc/op   new alloc/op    delta
BackendBlockTraceQL/sibling-8     267MB ±43%      218MB ±73%     ~     (p=0.381 n=5+5)
BackendBlockTraceQL/desc-8        153MB ± 1%      153MB ± 9%     ~     (p=0.730 n=4+5)
BackendBlockTraceQL/child-8       152MB ± 3%      150MB ± 3%     ~     (p=0.968 n=5+5)

name                           old allocs/op  new allocs/op   delta
BackendBlockTraceQL/sibling-8     3.41M ± 8%      3.30M ±10%     ~     (p=0.952 n=5+5)
BackendBlockTraceQL/desc-8        3.15M ± 0%      3.15M ± 0%   +0.03%  (p=0.008 n=5+5)
BackendBlockTraceQL/child-8       3.15M ± 0%      3.15M ± 0%   +0.03%  (p=0.008 n=5+5)

Queries
These queries don't even return on main. A single pass takes ~5 minutes. Results are for this branch only.

{"sibling", "{ name != `` } ~ { name != `` }"},
{"desc", "{ name != `` } >> { name != `` }"},
{"child", "{ name != `` } > { name != `` }"},

name                           time/op
BackendBlockTraceQL/sibling-8     1.86s ± 6%
BackendBlockTraceQL/desc-8        3.35s ± 4%
BackendBlockTraceQL/child-8       2.06s ± 3%

name                           speed
BackendBlockTraceQL/sibling-8  10.2MB/s ± 6%
BackendBlockTraceQL/desc-8     6.11MB/s ± 4%
BackendBlockTraceQL/child-8    10.0MB/s ± 3%

name                           MB_io/op
BackendBlockTraceQL/sibling-8      19.0 ± 0%
BackendBlockTraceQL/desc-8         20.5 ± 0%
BackendBlockTraceQL/child-8        20.5 ± 0%

name                           alloc/op
BackendBlockTraceQL/sibling-8    1.36GB ± 1%
BackendBlockTraceQL/desc-8       1.42GB ± 0%
BackendBlockTraceQL/child-8      1.43GB ± 1%

name                           allocs/op
BackendBlockTraceQL/sibling-8     6.13M ± 0%
BackendBlockTraceQL/desc-8        6.22M ± 0%
BackendBlockTraceQL/child-8       6.22M ± 0%

[mdisibio]

These queries don't even return on main

Does that mean the changelog entry should be new FEATURE? 😄

[mdisibio]

Great performance improvement 👍