Build a BDB cache quicklier

bennymack has asked for the wisdom of the Perl Monks concerning the following question:

Dear Esteemed Monks,

I am looking for a way to create a BerkeleyDB cache file more quickly.

For example, I have a ~70MB cache with ~500_000 keys. On a machine with quick disk access it will build in about a minute but on a slow disk it can take quite a while.

I'm building the cache from a a Storable file FYI. I just want to turn the stored data structure into a BDB cache file as quickly as possible.

Is there possibly a way to build the entire cache in memory to avoid intermediate disk writes, then write the whole thing out to disk just once when it's done? Or any other solution would be fine.

Thanks in advance!

Comment on Build a BDB cache quicklier

Replies are listed 'Best First'.
Re: Build a BDB cache quicklier by jettero (Monsignor) on Dec 28, 2006 at 13:42 UTC
I'm under the impression that DB_File handles all the IO in efficient buffered way. So, I believe the complete answer to your question is to tie a hash to a `DB_File` and it will automagically handle efficiency. I have had problems with long term storage in Storable files and find that DB_File is also much more dependable (by comparison). -Paul	[reply] [d/l]
Re: Build a BDB cache quicklier by SheridanCat (Pilgrim) on Dec 28, 2006 at 13:42 UTC
This does not answer the question asked, but you did ask for other solutions. If you're just building a cache and don't need it to write it to disk, have you looked at memcached? It's simple to setup and has Perl bindings.	[reply]
Re^2: Build a BDB cache quicklier by perrin (Chancellor) on Dec 28, 2006 at 23:24 UTC
It's also slower than BDB and would start out empty each time the program starts. Probably not the right solution here.	[reply]
Re: Build a BDB cache quicklier by bennymack (Pilgrim) on Dec 28, 2006 at 16:06 UTC
Thanks for your replies. After a little brainstorming I decided to try building the cache in '/dev/shm' and then move it to harddisk once it was complete. This had the ever so pleasing affect of reducing the build time from 15minutes to 15 seconds! It also reduced the size of the built out cache for some reason. Took it from ~70MB to ~38MB?! I Can't even explain that but I'll take it. Anyway, I thought I would post this here for posterity in case anyone else needs this optimization in the future or if anyone would like to further discuss this method.	[reply]
Re^2: Build a BDB cache quicklier by Anonymous Monk on Dec 29, 2006 at 06:18 UTC
You could have also tried modifying the memory/cache limits for BerkeleyDB	[reply]


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