[SERVER-18926] Full text search extremely slow and uses a lot of memory under WiredTiger Created: 11/Jun/15 Updated: 08/Oct/16 Resolved: 17/Jun/15 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Text Search, WiredTiger |
| Affects Version/s: | 3.0.1, 3.0.4 |
| Fix Version/s: | 3.0.5 |
| Type: | Bug | Priority: | Critical - P2 |
| Reporter: | Bruce Lucas (Inactive) | Assignee: | David Storch |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
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| Backwards Compatibility: | Fully Compatible | ||||||||||||||||||||
| Operating System: | ALL | ||||||||||||||||||||
| Sprint: | Quint Iteration 5 | ||||||||||||||||||||
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| Description |
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Issue Status as of Jul 14, 2015 ISSUE SUMMARY A bug in this procedure may make $text and geoNear (i.e. $near or $nearSphere) long-running queries, which buffer intermediate query results, execute slowly. In particular, if a such a query yields y times and buffers d documents, the overall time spent in yield-preparation was O(yd). With the fix, the time complexity is reduced to O(y). This issue only appears when queries are performed against a mongod instance running with the WiredTiger storage engine. Instances running the MMAPv1 storage engine are not affected. USER IMPACT AFFECTED VERSIONS FIX VERSION Original descriptionCreated db with 5M docs full-text indexed as follows:
Then do a full-text search:
Finishes in about 10 seconds under mmapv1, ran for a several minutes without finishing under WT before I killed it. It also uses (possibly a lot) more memory under WT than mmapv1. It seems to be spending all its time in forceFetchAllLocs (itself, not callees), called from yield. This path is only exercised if storage engine has document-level locking, which explains why WT behaves differently than mmapv1.
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| Comments |
| Comment by Dave Withers [ 26/Jan/16 ] |
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will do, thanks. |
| Comment by J Rassi [ 26/Jan/16 ] |
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dwithers@spireon.com: could you please file a new ticket describing the issue you're encountering? Thanks. |
| Comment by Dave Withers [ 26/Jan/16 ] |
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did this issue regress back in mongo 3.0.8? |
| Comment by Githook User [ 17/Jun/15 ] |
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Author: {u'username': u'dstorch', u'name': u'David Storch', u'email': u'david.storch@10gen.com'}Message: Improves performance for query plans with a blocking stage when using the WiredTiger storage engine. |