[Interest] [Help]A big problem about accessing database using OCI driver plugin from qt application.‏

[Lincoln Ramsay]

On 30/10/12 5:25 PM, Xiaognag Wang wrote:
> You mean this big difference (7 seconds and 30 millisecond ) was 
> caused by cache?

Oh yes. There's a big difference between having 1 chunk of data sent 
from the server to the client and having the client poll the server 
every time your app says fetchNext(); The effect becomes even more 
pronounced as you increase the latency between your app and the database 
server (eg. if it's on a network instead of on the local machine).

> In my testing, query.next() just retured 256 records.
> and I can not find methods to set cache enable in qt, should I set 
> cache at oracle side?

If you're using oracle, you want to look at OCI_ATTR_PREFETCH_ROWS 
and/or OCI_ATTR_PREFETCH_MEMORY. See QSqlDatabase::setConnectOptions().

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