Hi Harshit, Just some thoughts:
Are you running on fast storage (pd-ssd on GCP)? What is the reason for having 65 shards with only 10-nodes and RF=1, having that many shards is creates overhead. RamBuffer of 200MB seems to small for large batches. Cheers, Renato > On 7 Aug 2026, at 12:29, Harshit Sharma <[email protected]> > wrote: > > Hii all > > We're looking for advice on reducing the time our indexing client waits for > Solr to acknowledge update requests. > > Our indexing throughput is currently limited primarily by the time taken > for each batched update request to complete. Before changing client-side > concurrency or scaling the application, we'd like to understand whether any > Solr-side optimisations could reduce this acknowledgement latency. > Production Environment > > - > > SolrCloud 9.6.1 > - > > 10-node cluster on GCP Compute Engine > - > > Two collections: > - > > ~180M documents (250+ GB, 65 shards) > - > > ~70M documents (180+ GB, 65 shards) > - > > Mostly RF=1 > - > > Implicit routing > - > > SolrJ client sending batched update requests (3k-4k documents/request) > - > > Hard commit every *30 minutes* (openSearcher=false) > - > > Soft commit every *15 minutes* > - > > ramBufferSizeMB=*200* > - > > TieredMergePolicy > - > > Default ConcurrentMergeScheduler > - > > StandardDirectoryFactory (MMapDirectory) > > What we're observing > > From the client side, a blocking update request typically takes: > > - > > ~700 ms for batches of 3,000 documents > - > > ~1.5 s for batches of 4,000 documents > > Occasionally we see several-second outliers, but the median latency remains > consistent even during peak query traffic. > > We aim to reduce this latency to increase indexing throughput. > Questions > > 1. > > For batched update requests in SolrCloud, what typically contributes > most to the acknowledgement latency (request distribution, update > processing, tlog fsync, merges, etc.)? > > 2. > > Which Solr metrics would you recommend checking first to identify where > this time is being spent? > > 3. > > Are there any Solr configuration settings that commonly have a > significant impact on update acknowledgement latency (merge policy, merge > scheduler, indexing buffer, commit settings, update log configuration, > etc.)? > > 4. > > Has anyone run into similar indexing latency at this scale (60+ shards, > ~200M documents), and if so, what changes provided the biggest improvement? > > We'd appreciate any suggestions or best practices to reduce update request > latency and improve indexing throughput. Please let us know if any > additional configuration details or metrics would be helpful. > > > Thanks & Regards > > Harshit Sharma
