perf(l1): revert optimistic transactions in rocksdb and remove the explicit configured cache

[rodrigo-o]

Motivation

This PR reduces memory by 40~50%

Description

This PR sits is basically #4839 but instead of starting from #4821 it starts from main, and after different testing scenarios we came up with this cut in memory:

• reverts fix(l1): use transactional database with RocksDB #4599
• removes the rocksdb cache explicit setup

The caveat is that it appears to be 50% slower, we need to make specific measures to validate the results seen in #4839 (no longer the case, see #4853 (comment))

[github-actions]

Lines of code report

Total lines added: 0
Total lines removed: 12
Total lines changed: 12

Detailed view

+-------------------------------------------+-------+------+
| File                                      | Lines | Diff |
+-------------------------------------------+-------+------+
| ethrex/crates/storage/store_db/rocksdb.rs | 1238  | -12  |
+-------------------------------------------+-------+------+

[rodrigo-o]

Here we have some initial measurements for backing the 40~50% of memory reduction mentioned in this PR. We are right now testing it again without storage_chunk: #4839 (comment). Here is an initial measurement for the first ~3hours in mainnet:

Node Memory (RSS) & Host memory in mages

Main	This PR
Mean: ~16GB & Max: ~22GB	Mean: ~8GB & Max: ~15GB

[Copilot]

Pull Request Overview

This PR reverts optimistic transactions in RocksDB and removes explicit cache configurations to reduce memory usage by 40-50%. The changes replace OptimisticTransactionDB with standard DBWithThreadMode and remove cache-related options from RocksDB configuration.

• Replace OptimisticTransactionDB with DBWithThreadMode across all RocksDB implementations
• Remove explicit cache setup and cache-related block options to reduce memory footprint
• Update batch operations to use standard WriteBatch instead of WriteBatchWithTransaction

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
crates/storage/trie_db/rocksdb_locked.rs	Updated type signatures to use DBWithThreadMode instead of OptimisticTransactionDB
crates/storage/trie_db/rocksdb.rs	Replaced optimistic transaction DB with standard DB and updated batch operations
crates/storage/store_db/rocksdb.rs	Removed cache configuration and replaced optimistic transactions with standard DB operations
CHANGELOG.md	Added entry documenting the memory optimization changes

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[github-actions]

Benchmark Block Execution Results Comparison Against Main

Command	Mean [s]	Min [s]	Max [s]	Relative
base	89.080 ± 0.128	88.787	89.230	1.00
head	89.139 ± 0.167	88.860	89.322	1.00 ± 0.00

[rodrigo-o]

We are going to make this changes behind a low-memory flag to avoid the snap sync time regression when we prefer a quicker syncing.

After pathbased, this PR doesn't reduce performance as measured before. Right now snapsync takes the same time with and without optimistic transactions.