Subject Re: R: [IB-Architect] What will make InterBase more attractive?
Author Jim Starkey
At 10:23 PM 4/8/00 +0200, Paolo Fainelli wrote:
>How does IB decide which page discard from cache when it run low on memory ?
>Do you think database caching mechanism can be inproved ?

Page replacement is simple least recently used (LRU). Writes are more
complex. Interbase depends on a page write strategy called careful
write, which ensures that the database on disk is always valid and
consistent. To support this, the cache maintains precedence relationships
to make sure that pages get written in the proper sequence. There
is a fair bit of housekeeping to keep everything both correct and

Interbase originally used a weighted LRU schema for was more
efficient for a small number of numbers (bad old days when memory
was cheap). At some point it was noticed that the "optimization"
was more expensive than the gain, the aging schema was replaced
with LRU.

Jim Starkey