Re: Loading tables in Shared Memory
On Mar 23, 8:22am, peeyush wrote: > Subject: Loading tables in Shared Memory > Hi Mickey, > > Thank You for your response. Im sorry I did not clarify that I am NOT > talking about loading the table into INFORMIX SHARED MEMORY, but creating > our own SHared Memory in UNIX, and then loading the table into it. I have > done it in my earlier project, but that was 2 years back so I have forgotten > how to do it. > > But it IS possible. I know that one has to use esqlc code to access the > shared memory (as system calls are involved). > > Regards, > > Peeyush I'm not sure why you would want to bother. Any table that is accessed enough that you would seriously consider doing this would, when using standard SQL access, also be permanently stored in the Informix shared memory buffers once the system had been running for a short while. This is because Informix uses least recently used queues to decide which buffer pages to overwrite. If the index and data pages of the table haven't been used for enough time that the Informix LRU queues would actually consider them as candidates for replacement then I'd be unsure of the worth of storing them permanently in memory. With this scenario I'm not sure I see the benefit of creating your own shared memory area when that means you also have to write all your own memory access code to index and reach the data. You also need code to load the data into the shared memory area in the first place. Plus locking and write back code to handle updates, if required. How about just increasing the Informix buffer allocation? Or is it that for your requirements you find the overhead of access through the Informix engine to the shared buffer pool too slow? Is this a realtime system? Cheers - Jim -- ----------------------------------------------------------------------------- Jim Gordon DHL Airways Inc. jgordon@us.dhl.com ----------------------------------------------------------------------------- My opinions are my own. They may vary with time but they remain mine!