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Re: questions about LMDB

Shu, Xinxin wrote:
Several other questions about lmdb

1) does lmdb store one key-value pair in a single page? How lmdb organizes these key-value pairs in a single page
2)  if size is larger than single page size , how lmdb process this request?

This list is for developers to discuss actual coding issues inside the OpenLDAP code; your questions are too elementary and don't belong here. Use the -technical list for user-oriented questions.

Any help will be appreciated ? thanks


-----Original Message-----
From: Shu, Xinxin
Sent: Thursday, March 19, 2015 3:49 PM
To: openldap-devel@openldap.org
Cc: Shu, Xinxin
Subject: questions about LMDB

Hi list ,

Recently I read docs about lmdb , there are two sentences
1) readers do not block writers
2) writers do not block readers
I can understand 'readers do not block writers' , but cannot understand the second one , can someone help explain , how lmdb achieve 'writers do not block readers',  below is my understandings , please correct me if anything wrong.
  if the access pattern is write - read, since lmdb only support two version of data ,  when the write has been started but not committed ,  the concurrent read may read stale data since write has not been committed.


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  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/