[DOCS-4484] Document that mongoS no longer pins connections to secondaries Created: 08/Dec/14  Updated: 16/Mar/15  Resolved: 22/Dec/14

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: v1.3.16, mongodb-2.6, mongodb-3.0

Type: Improvement Priority: Major - P3
Reporter: Michael Paik Assignee: Sam Kleinman (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Documented
documents SERVER-9788 mongos does not re-evaluate read pref... Closed
Participants:
Days since reply: 9 years, 9 weeks ago

 Description   

As of server 2.8 and server 2.6.4, mongoS no longer pins secondary connections to allow changes in read preferences between queries.

Special attention, from ticket: "As these changes could not be backported to 2.6, a different fix was implemented specifically for 2.6: a new mongos server parameter, internalDBClientRSReselectNodePercentage was introduced. This can be set to any value from 0 to 100 (defaults to 0) and represents the probability (expressed in percentage) of a replica set connection in mongos to reevaluate replica set node selection from scratch, regardless of the compatibility of the current read preference to the last-used secondary node. Extra care should be taken since reselecting a replica set node will destroy the old connection and create a new connection. This means in extreme cases (for example, 100%), mongos can be creating and destroying connections for every read request."

Text re: pinning at http://docs.mongodb.org/manual/core/read-preference-mechanics/ should be changed.

See linked.



 Comments   
Comment by Githook User [ 17/Dec/14 ]

Author:

{u'username': u'tychoish', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'}

Message: DOCS-4484: release notes
Branch: master
https://github.com/mongodb/docs/commit/8f9e16e7a218aaa50f14b6983b72e5c0ee4e8a6e

Comment by Githook User [ 17/Dec/14 ]

Author:

{u'username': u'tychoish', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'}

Message: DOCS-4484: read preference change for mongos
Branch: master
https://github.com/mongodb/docs/commit/01e2614bf25e57b2bf121f2e3d654f648e61952d

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