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Type: Improvement
Resolution: Done
Priority: Major - P3
Fix Version/s: 3.2.13, 3.4.3, 3.5.4
Affects Version/s: None
Component/s: Storage
Labels:
- PM248
- bkp
- commands
- listDatabases
- performance
Environment:
Linux yq131 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
ext4 filesystem

Backwards Compatibility:
Fully Compatible
Backport Requested:

v3.4, v3.2
Sprint:
Storage 2017-03-06
Confidence Status:
None
Work Order:
3
CAR Domain/s:
None

Aha! Reference:
None
Tracking Level:
None
Risk Status:
None
Exec Notes:
None
Goal Name(s):
None
Goal Link:
None

I have about 29377 files (including datafile and nsfile), 13666 databases. The total size is about 1TB. The mongod started with parameters "smallfiles" and "noprealloc".
When I run the command listDatabases, it takes too long on calculating "sizeOnDisk" and determining the empty of database, more than a hour sometimes. But I just need a list of database names. An option to not display size or empty probably makes sense.
I found that mongod will receive the listDatabases command in the following cases:
1. Dump all databases use mongodump
2. A Member of replica set doing initialSync
3. Add a new shard to a cluster.
In these cases, listDatabases may cause mongod overload and can not do the normal queries.

is depended on by

SERVER-28924 Change databasesCloner to use the "nameOnly" version of listDatabases

Closed

SERVER-28925 Use listDatabases({'nameOnly': true}) in the addShard implementation

Closed

is duplicated by

SERVER-24948 initial sync failed because listDatabases exceeded 30s socket (read) timeout

Closed

SERVER-27666 listDatabases performance issue w/ replicasets & wiredTiger

Closed

SERVER-21066 Investigate listDatabases option to return only dbnames and skip sizes

Closed

is related to

TOOLS-1653 use the new higher performance listDatabases() in mongodump, et. al.

Closed

SERVER-6898 Allow all authenticated users to run listDatabases

Closed

SERVER-21067 Investigate having the storage size of a given collection/index/database cached within the WT/KV api

Closed

related to

SERVER-11051 listDatabases command reports existence of databases that have never been written to.

Closed

(3 is related to, 1 related to)

Assignee:: Geert Bosch
Reporter:: Lei Zhang
Participants:: Chad Kreimendahl, Eric Milkie, Geert Bosch, Githook User, Lei Zhang, Scott Hernandez, Zhang Youdong
Votes:: 10 Vote for this issue
Watchers:: 27 Start watching this issue

Created:: Jun 02 2011 03:48:41 AM UTC
Updated:: Nov 15 2021 03:11:40 PM UTC
Resolved:: Feb 20 2017 02:45:48 AM UTC
Confidence Status Last Update:: 24/Jan/17 3:18 PM

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