[SERVER-9924] writing to a sharded collection vs an unsharded collection shows a 50-60% throughput drop off Created: 13/Jun/13 Updated: 21/Jun/13 Resolved: 20/Jun/13 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | 2.4.3 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Critical - P2 |
| Reporter: | Edouard Servan-Schreiber | Assignee: | Osmar Olivo |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Operating System: | ALL |
| Participants: |
| Description |
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when doing inserts with a single thread to an unsharded collection in a cluster of 4 shards, we observed a throughput of ~4k inserts/sec. The sharded collection was well balanced and the throughput was well balanced across all shards (~400 inserts/sec/shard). This was done on a single machine with an SSD, 4 mongod's running as a sharded cluster with single replica shards. What could explain such a performance drop off? |
| Comments |
| Comment by Osmar Olivo [ 21/Jun/13 ] |
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The test scripts were not written by 10gen initially and thus cannot be posted publicly by us. The negative results were a product of human error. Thanks. |
| Comment by vinay pothnis [ 20/Jun/13 ] |
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Hi there, Could you please post the test script and elaborate on the error in the test? Thanks! |
| Comment by Edouard Servan-Schreiber [ 20/Jun/13 ] |
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Full tests observe only a 10% slowdown between a manual sharding approach (direct loading into mongod's) and sharded approach leveraging mongos. Product works as designed. |
| Comment by Edouard Servan-Schreiber [ 13/Jun/13 ] |
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any news on this? |