Re: [boost] ACID transactions/flushing/MySQL InnoDB

Subject: Re: [boost] ACID transactions/flushing/MySQL InnoDB
From: Phil Endecott (spam_from_boost_dev_at_[hidden])
Date: 2009-12-10 18:04:31

Hi Stefan,

Stefan Strasser wrote:
> writing 512 bytes, aligned to 512 bytes, without O_CREAT, when the file 
> already exists, brings the desired results
> 2 seconds with much less disk usage.
> that's some set of conditions.

I would be interested to know how this compares to mmapping the file 
and then writing to memory and calling msync().

I while ago I did some work on a transactional persistent object 
library for "write mostly" data.  Since it didn't need to support 
efficiently erasing or modifying existing data it could use a pure log 
structure with transactions implemented just by atomically adjusting 
the end-of-data offset.  I did this all via mmapped files and the 
performance seemed good enough, but I never benchmarked it against e.g. 
MySQL.  Actually it has been on hold since I discovered how badly it 
performs over NFS...

Phil.