Re: [sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread Isaac Raway
On 12/1/06, Isaac Raway <[EMAIL PROTECTED]> wrote: > Because our project needs to be ported to windows - the /dev/shm is not an > option - because win2000 does not support any temporary memory based file > system. Not so. "FILE: Ramdisk.sys sample driver for Windows 2000" http://support.microso

Re: [sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread Isaac Raway
Because our project needs to be ported to windows - the /dev/shm is not an option - because win2000 does not support any temporary memory based file system. Not so. "FILE: Ramdisk.sys sample driver for Windows 2000" http://support.microsoft.com/kb/257405 Even includes C code, along with a bina

Re: [sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread John Stanton
Eduardo Morras wrote: At 09:34 01/12/2006, you wrote: Hi there, we are on an challanging project with very high requirements on performance. When doing some debugging we discover, that the sqlite method for creating an memory-based database is much slower than using e.g /dev/shm on linux or

Re: [sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread Eduardo Morras
At 09:34 01/12/2006, you wrote: Hi there, we are on an challanging project with very high requirements on performance. When doing some debugging we discover, that the sqlite method for creating an memory-based database is much slower than using e.g /dev/shm on linux or /tempfs on solaris. (We ha

Re: [sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread drh
John Stanton <[EMAIL PROTECTED]> wrote: > > I understand that Sqlite uses a less efficient algorithm for :memory > files than for the cacheing on regular files and that means lower > performance on those memory DBs. > It uses exactly the same algorithm. It is just that the hash tables are fix

Re: [sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread John Stanton
You might discover that a memory based database has few advantages over a disk based one, since Sqlite uses cacheing and the OS uses virtual memory file cacheing. The main difference might be initial accesses being slower while the cache fills up. I understand that Sqlite uses a less efficien

Re: [sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread Dennis Cote
[EMAIL PROTECTED] wrote: Hi there, we are on an challanging project with very high requirements on performance. When doing some debugging we discover, that the sqlite method for creating an memory-based database is much slower than using e.g /dev/shm on linux or /tempfs on solaris. (We have meas

[sqlite] for what reason :memory: is much slower than /dev/shm/dummy.db

2006-12-01 Thread roland . gremmelspacher
Hi there, we are on an challanging project with very high requirements on performance. When doing some debugging we discover, that the sqlite method for creating an memory-based database is much slower than using e.g /dev/shm on linux or /tempfs on solaris. (We have measured an 20min performance a