Improve the speed of access read-only

Hello

I am interested in improving the performance in an application that performs the reading, not writing. I have a very short sample application, written in c:

http://limnus.com/~Ken/Berkeley.c

It simply opens a cursor on the DB, iterates through all the records, then closes. The first time I run the present, it takes about 30 minutes to move through all the records. The second time I run it, it only takes about 7 seconds. I conclude that the second time, the data are cached by the OS file system cache.

My DB is a Btree, with about 9 million documents and a total area of about 750 M.

I was hoping that if I used DB_RDONLY and a cache of 1 G (i.e. longer than the DB), that I'd get mmap to read all records in very fast memory.

Any ideas for improvement? Anyone see any problem with the way I coded the sample application? Using an environment would offer benefits?
I tried using DB_MULTIPLE_KEY to recover documents in bulk (size of the buffer of 32 M), but I don't see any improvement.

Thank you.

-Ken

Hi Ken. Please take a look at this idea of pre-filling hide via the pool memory API:
Re: a question about read file or cache

Ben Schmeckpeper

Tags: Database

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