CC technical list

Cheers, xinxin

-----Original Message----- From: openldap-devel [mailto:openldap-devel-bounces@openldap.org] On Behalf Of Shu, Xinxin Sent: Friday, March 20, 2015 8:50 AM To: Howard Chu; openldap-devel@openldap.org Subject: RE: questions about LMDB

Sorry for the wrong mail list , I will forward this request to technical list

Cheers, xinxin

-----Original Message----- From: Howard Chu [mailto:hyc@symas.com] Sent: Thursday, March 19, 2015 11:52 PM To: Shu, Xinxin; openldap-devel@openldap.org Subject: 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

Cheers, xinxin

-----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.

Cheers, xinxin