Investigate and document goleveldb configs to identify potential improvements

[p0mvn]

Background

We would like to investigate and document all potential improvements from goleveldb configurations and design.

goleveldb settings we use are mainly in:

• https://github.com/tendermint/tm-db/blob/master/goleveldb_batch.go
• https://github.com/tendermint/tm-db/blob/master/goleveldb.go

options for levelDB / the defaults:

• https://github.com/syndtr/goleveldb/blob/master/leveldb/opt/options.go#L24

ETH’s levelDB: v
-https://github.com/ethereum/go-ethereum/blob/4d086430bd8c0b9549fde5259f74f6df6c96df65/ethdb/leveldb/leveldb.go

Acceptance Criteria

• Does it make sense to turn off seek compaction?
• Should we override other defaults in the goleveldb config?
• Set up goleveldb telemetry and analyze the results
• Any other potential optimizations?

[p0mvn]

Potential Optimization 1

Status: Not pursuing

While looking into go-ethereum, I noticed that they recently implemented a pre-allocated batch buffer.

Apparently, level db is very inefficient when growing the batch buffer at once. It is better to pre-allocate the buffer.

Since we commit a bunch of data at once in SaveVersion , I thought that this would be a good optimization.

However, after creating a relevant PR #29 , I observed that the overhead from pre-calculating batch size outweighs the costs. The results are documented here: #31

[p0mvn]

Potential Optimization 2

Status: Not pursuing

In ethereum/go-ethereum#15115, go-ethereum introduces batches that are committed in sizes of 100Kb. According to their benchmarks, this has been proven to be the most optimal for compaction.

To implement this on our side, we would have to significantly redesign IAVL because introducing a similar change would currently break the commit atomicity

[p0mvn]

Potential Optimization 3 - Seek compaction

Status: In progress
There are multiple reports that turning off seek compaction improves the compaction process:

• How seek compaction works? google/leveldb#857
• database: disable seek compaction for LevelDB klaytn/klaytn#715
• ethdb/leveldb: disable seek compaction ethereum/go-ethereum#20130

We should try implementing something similar and benchmark the results.

[p0mvn]

Potential Optimization 4

Status: TBD

To look into this fork and see if we can adopt anything:
https://github.com/line/tm-db/commits/main