Question

I have developed a program which uses SQLite 3.7 … database, in it there is a rather extensive write/read module that imports , checks and updates data. This process takes 14 seconds on my PC and Im pleased as punch with the performance.

I use transactions for everything with paratetrs my PC is a Intel i7 with 18gig of ram. I have not set anything in the database. I used SQLite Expert to create the database and create the data structures including table and columns and checked that all indexes are created. In other words its all OK.

I have since deployed the program/database to 2 other machines. That 14 second process takes over 5 minutes on the other machines. Same program, identical data, identical database. The machines are upto date, one is a 3rd gen Intel i7 bought last week, the other is quite fast as well so hardware should not be an issue.

Im just not understanding what the problem could be? Is it the database itself ? I have not set anything other then encription on it. Remembering that I run the same and it takes the 14 seconds. Could it be that the database is ‘optimised’ to my PC ? so when I give it to others its not optimised?

I know I could turn off jurnaling to get better performance, but that would only speed up the process and still would leave the problem.

Any ideas would be welcome.

EDIT:
I have tested the program on my 7yo Dual Athelon with 3gig of ram running XP on HDD, and the procedure took 35 seconds. Well in tolerable limits considering. I just dont get what could be making 2 modern machines take 5 min ?
I have an idea that its a write issue, as using a reader they are slower but quite ecceptable.

Answer 1

• SQLite speed is affected most by how well the disk does random reads and writes; any SSD is much more better at this than any rotating disk.
• Whenever changes overflow the internal cache, they must be written to disk. You should use PRAGMA cache_size to increase the cache to more than the default 2 MB.
• Changed data must be written to disk at the end of every transaction. Make sure that there are as many changes as possible in one transaction.
• If much of your processing involves temporary tables or indexes, the speed is affected by the speed of the main disk. If your machines have enough RAM, you can force temporary data to RAM with PRAGMA temp_store.
• You should enable Write-Ahead Logging.

Note: the default SQLite distribution does not have encryption.