L1 arrow compaction

[thorfour]

It may be useful to have the option to compact L0 arrow records into L1 arrow records instead of Parquet.

[thorfour]

This may only be worth pursuing once the REE support changes are in FrostDB as well as the record sorting implementation apache/arrow#34719 is completed

[asubiotto]

Agreed. I think moving to arrow-only in-mem would be the last step in this quarter.

[gernest]

I am thinking about this, I was wondering if this is the same as arrowutils.MergeRecords(arrow_parts...) |> arrowutils.SortRecord |> parts.NewArrowPart ?

[asubiotto]

Yes, although given the arrow parts should be merged on input, there probably isn't a need for the downstream sort. I'd also be interested in getting some L0 to L1 stats on how much memory we reduce through arrow compaction vs parquet compaction.

[gernest]

@asubiotto can you expand a bit about memory expectation between arrow/parquet compaction ?

I was always under the impression parquet+compression gives better memory saving than arrow.

[asubiotto]

Yes, this is why I'd be interested in getting some numbers so we are informed about the tradeoffs. Intuitively, dictionary encoding should go a long way. We've also been thinking about experimenting with run end encoding in arrow.

[github-actions]

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[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.