Re: ra_pages and io rate

STOP RIGHT THERE! Do NOT try to tune Informix in the same way that you tune Oracle. Don't even think about how you would tune Oracle when tuning Informix. The implementations are completely different. hopehope_123 said: > > Hi Richard , > > Lets say that i use pdq . Does pdq allow me to read data by using > higher rates? Or does it just make the query run faster because of the > parallelism? > I can also run this query parallel in oracle . If we compare the > sequental scan performance of both databases , oracle suggests to use > db_file_multiblock_read_Count parameter which allows up to 1mb. per > read and informix has ra_pages parameter still can read page_size > blocks , can we say that oracle is better? No. They way that the two products approach their disk access is completely different.. > For an example think about a 1Mb. table . If i use oracle in order to > read , > with proper setting i can read the whole table by issuing only 1 disk > read. In informix , after setting the ra_xx parameter i still read > multiple page size blocks. Art says that i had better no to try to > optimize an informix query like oracle and i 100% agree with him , but > what approach do i need to follow? Why would you want to read the entire table in one shot? > By the way , The last version i use is informix 9.2 and in order to > use parallel query i need to set pdqpriority . > What i see with oracle 9.x is , executing parallel query seems much > more simpler: > > select /*+parallel(a,8)*/ count(*) from customer . SET PDQPRIORITY 10; SELECT COUNT(*) FROM CUSTOMER; How much more difficult is that? > And informix pdq needs special administration . Is it still same with > informix 10? What special administration? And why are you still on 9.2 when 9.4 is so much faster? -- Bye now, Obnoxio "C'est pas parce qu'on n'a rien ' dire qu'il faut fermer sa gueule" - Coluche A smile is a gift that is free to the giver and precious to the recipient. But giving someone the finger is free too, and I find it more personal and sincere. sending to informix-list