[Monotone-devel] Re: [PATCH] pre-cache database file to improve response time

[Joe Wilson]

Benoît Dejean wrote:
>>Le samedi 18 mars 2006 Ã 14:33 -0800, Joe Wilson a Ãcrit :
>> Here's a patch to improve the speed of many database-intensive monotone 
>> commands.
>> 
>> It can shave 70% of the time off of a (cold) checkout, for example.
>>
>>If your database fits in ram, and without swapping every other app and
>>file ...

...yet in spite of this, people still use DVD burning software to 
burn multi-gigabyte disk images while running background tasks.
The OS can swap pages back out just as easily.

If required, an upper pre-cache memory limit can be set easily enough.
The longer running monotone commands hit most pages in the database 
anyway. The speed up of many commands is quite dramatic.

Try the patch before forming an absolute opinion. It works quite 
well in practice and does not affect the other processes in my testing
(iTunes does not appear to be bothered).

Until SQLite uses mmap() instead of read(), I don't see another way to 
speed up monotone disk read access nearly as easily and effectively.

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