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From "Geir Magnusson Jr." <>
Subject Re: document insert rate
Date Sun, 04 Jan 2009 22:45:08 GMT

On Jan 4, 2009, at 5:38 PM, Damien Katz wrote:

> On Jan 4, 2009, at 4:11 PM, Geir Magnusson Jr. wrote:
>> On Jan 4, 2009, at 2:59 PM, Damien Katz wrote:
>>> What you say is possible, but doesn't seem too likely as I don't  
>>> ever recall any report of a corrupt db on Linux, but before the  
>>> F_FILESYNC change in Erlang we would see reports of corruptions on  
>>> OS X due to power loss. Since the change, we've had no reports of  
>>> corrupt databases on OS X or Linux.
>> Have you seen the correlation between the # of pirates and global  
>> warming? :)
>> There may be correlation here between the Erlang update and  
>> corruption, but I don't see the causality -  fsync() on linux  
>> should only get as far as the on-device buffering if it does write  
>> buffering, whereas if the OS X docs are truthful, the F_FILESYNC  
>> fcntl() pushs the bits to the rust on the platter.  Maybe they  
>> fixed something else in that erlang update, or maybe the universe  
>> is smiling upon CouchDB users or ....
>>> I don't think anyone else sees update performance that slow (I'm  
>>> assuming these are fairly small documents?), I'd guess there is  
>>> something particular about your setups. Since it involves update  
>>> speed it wouldn't be the javascript engine. It's possible it's the  
>>> openssl interface, I've seen instances of wacked openssl installs  
>>> that slowed down Erlang but didn't crash it.
>> I have an idea.... try it. I bet you can't get better than that  
>> (6-8  inserts per second) on Mac OS X unless you have stupid-fast  
>> disks (like maybe an SSD).
>> Even get a "back of the envelope" approx using time and curl - that  
>> came in at the same rate as Ruby, JS and Java test programs.
>> Everyone who has tried my experiment on IRC has reported the same  
>> numbers.  I can get 6/sec on a laptop (2.5GHz core2 dual core MBP  
>> w/ 4GB ram and a 7200rpm disk), and 8/sec on my desktop (a quad- 
>> core, 8 GB w/ raided 7200rpm disks, IIRC)
>> geir
> Okay, very well. If you find evidence this is broken on Linux  
> systems, please file a bug.

How many inserts a second can you do on your machine?


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