deepakpanda93 commented on issue #11273:
URL: https://github.com/apache/hudi/issues/11273#issuecomment-4851161429

   Hello @SuneethaYamani 
   
   As @ad1happy2go noted, the "compaction" you see on a COPY_ON_WRITE table is 
the metadata table compacting — the MDT is always Merge-On-Read internally, so 
it schedules compaction independent of your data table's type. That part is by 
design.
   
   On the slow MDT compaction (~5h with RECORD_INDEX):
   
   - It's governed by hoodie.metadata.compact.max.delta.commits (default 10). 
You can't disable MDT compaction while keeping the metadata table — compaction 
is what keeps the MDT log files bounded and reads fast. Setting it very high 
(e.g. 365) avoids the periodic cost but lets MDT log files grow, which then 
slows MDT reads, so it's not a good long-term setting.
   - Since RLI (hoodie.index.type=RECORD_INDEX) requires the metadata table, 
disabling the MDT isn't an option if you want RLI.
   - Recent 1.x releases include significant MDT / record-index performance 
improvements (e.g. HUDI-6200 [#8684](https://github.com/apache/hudi/pull/8684) 
for larger indexes). Please retest MDT compaction time on a recent 1.1.x 
release with default compact.max.delta.commits.
   
   If MDT compaction is still an unacceptable bottleneck on 1.x, please share 
the MDT compaction metrics (record_index size, delta-commit count, executor 
resources) and we'll dig into the performance. Thanks!


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