Split DatabaseTableUpdate in deletes/inserts vecs

[Centril]

Description of Changes

• DatabaseTableUpdate is split into two separate vectors for deletes / inserts. This was helpful for performance as it meant we could avoid some temporary allocations.
• The temporary allocations of Vec<_>s inside eval_{all, lhs, rhs} are removed. Instead, we carry iterators as long as possible. This helped performance.
• Incr eval now results in two separate vectors for inserts and deletes, so that DatabaseTableUpdateCow mirrors DatabaseTableUpdate. These are only fused at the very moment we convert to bsatn/json. This did not affect performance, but should in theory do less work as well as being cleaner.

Performance

Benchmarking incr-select: Collecting 100 samples in estimated 5.0004 
incr-select             time:   [193.77 ns 196.76 ns 201.67 ns]
                        change: [-55.774% -55.392% -54.906%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 13 outliers among 100 measurements (13.00%)
  2 (2.00%) high mild
  11 (11.00%) high severe

Benchmarking incr-join: Collecting 100 samples in estimated 5.0049 s 
incr-join               time:   [1.8449 µs 1.8683 µs 1.8983 µs]
                        change: [-30.666% -30.236% -29.737%] (p = 0.00 < 0.05)
                        Performance has improved

Commit 3 should have no noticable perf impact and is mostly cleanup.

Relative to master, on i7-7700K, 64gb ram.

API and ABI breaking changes

None

Expected complexity level and risk

2

Testing

No changes in semantics.

[Centril]

@gefjon has already reviewed the contents of this but @joshua-spacetime probably also wants a look.

[bfops]

Bot test results

Conclusion: ✔️ Possibly some small improvements?

Commits tested

before:

commit cb9d493d46897ee84cc13eeb0fdd7e0063d747af (origin/bfops/perf-test-before)
Merge: af73b29b 0ad01b77
Author: Zeke Foppa <196249+bfops@users.noreply.github.com>
Date:   Mon Mar 25 14:47:25 2024 -0700

    [bfops/perf-test-before]: Merge remote-tracking branch 'origin/bfops/enable-tracy' into bfops/perf-test-before

commit af73b29b5f687c95863772936dafaeea94c5ceaa
Author: Tyler Cloutier <cloutiertyler@aol.com>
Date:   Thu Mar 21 21:19:31 2024 -0700

    Made me the codeowner of the traits.rs file for the datastore

after:

commit 64b692f174247c5a47a4c79472dbdbc9c35c192a (HEAD -> bfops/perf-test-after, origin/bfops/perf-test-after)
Merge: 3fb3e4b8 0ad01b77
Author: Zeke Foppa <196249+bfops@users.noreply.github.com>
Date:   Mon Mar 25 14:47:29 2024 -0700

    [bfops/perf-test-after]: Merge remote-tracking branch 'origin/bfops/enable-tracy' into bfops/perf-test-after

commit 3fb3e4b83703a0af857cf1880a99961fa9670404 (origin/centril/split-dbt)
Author: Mazdak Farrokhzad <twingoow@gmail.com>
Date:   Wed Mar 20 21:37:50 2024 +0100

    store deletes/inserts separately in eval_incr results; mostly cleanup

commit 1ae9f524b5f0fd12207af2e5fbea0d0c8797a4e8
Author: Mazdak Farrokhzad <twingoow@gmail.com>
Date:   Wed Mar 20 14:12:02 2024 +0100

    incr-join: avoid temp Vec<_> allocs

commit d082c00f7588a8bbaddfd8a76b9dee171dcad7cf
Author: Mazdak Farrokhzad <twingoow@gmail.com>
Date:   Wed Mar 20 23:01:06 2024 +0100

    split DatabaseTableUpdate in deletes/inserts vecs

commit 0fc5b2476f866013596b205ea3f18b1b5997397c (origin/centril/perf-eval-incr-ref)
Author: Mazdak Farrokhzad <twingoow@gmail.com>
Date:   Fri Mar 22 00:28:23 2024 +0100

    use MemTable less

call_reducer

call_reducer_with_tx

eval_incr

eval_updates

enemy_ai_agent_loop

npc_ai_agent_loop

[joshua-spacetime]

DatabaseTableUpdate is split into two separate vectors for deletes / inserts. This was helpful for performance as it meant we could avoid some temporary allocations.

Can you expand on this point? Which allocations does this allow us to get rid of and where?