[SERVER-16353] listDatabases is very slow on wiredtiger primary Created: 30/Nov/14 Updated: 14/May/15 Resolved: 12/Dec/14 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Storage |
| Affects Version/s: | 2.8.0-rc1 |
| Fix Version/s: | 2.8.0-rc3 |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Cailin Nelson | Assignee: | Matt Kangas |
| Resolution: | Done | Votes: | 0 |
| Labels: | wiredtiger | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
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| Backwards Compatibility: | Fully Compatible | ||||||||
| Operating System: | ALL | ||||||||
| Participants: | |||||||||
| Description |
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On a process with 67 databases, the following takes approximately 2 seconds on a wiredTiger primary:
If I switch the primary to an mmapv1 node, the command returns within a few milliseconds. |
| Comments |
| Comment by Asya Kamsky [ 14/May/15 ] | ||||||||||||||||||||||||||||||||||
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paul.reed since this ticket is closed and you would like a different variant of list databases command I would recommend opening a new ticket asking for additional command (or option to command) to return "fast list" of DB names. | ||||||||||||||||||||||||||||||||||
| Comment by Paul Reed [ 13/May/15 ] | ||||||||||||||||||||||||||||||||||
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Have to say that this just isn't fixed - or has regressed. Sometimes it will take my server over 2 minutes to return. Especially if I have multiple clients running. | ||||||||||||||||||||||||||||||||||
| Comment by Matt Kangas [ 12/Dec/14 ] | ||||||||||||||||||||||||||||||||||
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Resolved as of d3877ce. With the attached testListDatabases.js, runCommand listDatabases takes:
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| Comment by Githook User [ 05/Dec/14 ] | ||||||||||||||||||||||||||||||||||
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Author: {u'username': u'benety', u'name': u'Benety Goh', u'email': u'benety@mongodb.com'}Message: | ||||||||||||||||||||||||||||||||||
| Comment by Matt Kangas [ 04/Dec/14 ] | ||||||||||||||||||||||||||||||||||
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Simple jstest | ||||||||||||||||||||||||||||||||||
| Comment by Steve Briskin (Inactive) [ 30/Nov/14 ] | ||||||||||||||||||||||||||||||||||
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I don't think it's proportional to the number of collections. I have 4 DBs with 1 collection in each and "show dbs" took over 20s to come back. Example:
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| Comment by Anil Kumar [ 30/Nov/14 ] | ||||||||||||||||||||||||||||||||||
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Apparently this is the behaviour proportional to number of collections. Even on a single database, larger number of collections will cause slow listDatabases, although there is only one database. |