[Pgpool-hackers] Progress report: on memory query cache

[Huang Bambo]

Hi,

> Now cache on shmem is managed by a hash table which is on shmem as
> well. Since shmem cannot be expanded dynamically, the max number of
> entries in the hash table is also fixed. For this I have added new
> directive called "memqcache_max_num_cache" which specifies the max
> number of hash table entries. If the number of cache entries exceed
> it, simply an error is triggered at this point. Maybe we could trash
> away old cache entries and make a room to have hash entries in this
> case.

I don't agree that if cached entries exceed the limit, give a error,
instead I suggest not to cache those entries that always exceed the
limit because generally those query don't need high performance.

Bambo Huang