[ISSUE #10270] Make Pop RocksDB BlockCache size configurable via MessageStoreConfig

[lizhimins]

Add popRocksdbBlockCacheSize to MessageStoreConfig with a default of 256MB, replacing the hardcoded value in RocksDBOptionsFactory.createPopCFOptions(). This allows operators to tune Pop RocksDB memory usage based on container memory budgets.

Which Issue(s) This PR Fixes

• Fixes [Enhancement] Make Pop RocksDB BlockCache size configurable via MessageStoreConfig #10270

Brief Description

How Did You Test This Change?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 52.94118% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.90%. Comparing base (f04eafc) to head (ea67835).

Files with missing lines	Patch %	Lines
...ache/rocketmq/store/config/MessageStoreConfig.java	25.00%	6 Missing ⚠️
.../rocketmq/store/rocksdb/RocksDBOptionsFactory.java	0.00%	2 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10271      +/-   ##
=============================================
- Coverage      48.96%   48.90%   -0.06%     
+ Complexity     13461    13450      -11     
=============================================
  Files           1375     1375              
  Lines         100436   100448      +12     
  Branches       12971    12971              
=============================================
- Hits           49178    49127      -51     
- Misses         45266    45322      +56     
- Partials        5992     5999       +7     

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[qianye1001]

Thanks for making the Pop RocksDB BlockCache size configurable — this is a good step toward better memory tuning in container environments.

One thing worth considering: blockCacheSize is only part of the memory footprint. In createPopCFOptions(), writeBufferSize (128 MB) and maxWriteBufferNumber (4) are still hardcoded, which means the memtable alone can consume up to 512 MB. For memory-constrained containers, this is just as significant as the block cache.

It would be great to also expose writeBufferSize and maxWriteBufferNumber (and possibly minWriteBufferNumberToMerge) as configurable fields in MessageStoreConfig, so operators can holistically tune the Pop RocksDB memory budget. Otherwise, someone who carefully tunes the block cache down may still be surprised by the fixed memtable overhead.

Happy to discuss further if needed.

[qianye1001]

LGTM, thanks for the quick update!

[lollipopjin]

LGTM