C
ChUIMonster
Guest
Even without a network to traverse a SQL-92 query is going to go through an awful lot of overhead and through multiple context switches to get executed. Did you also connect and disconnect in your measurement? Either way I'm kind of surprised it was only 150ms. (HPUX isn't exactly a fast platform these days.) Software is, indeed, a huge part of the latency. When someone has a storage device external to their server there are many, many layers of software that handle the data. If there were not then one nanosecond per foot would probably be a decent measure of latency. But instead the data moves a few inches, gets processed within the the drive, moves a few more inches, gets processed by an adapter inside the storage array, moves a few more inches, gets processed by the fancy logic within the array that supposedly magically makes everything fast, then gets passed to a network adapter... travels for a few feet and runs into a switch which then processes it some more, repeat until we get to the server, then we go through a network adapter and on through to the CPU that asked for that data an eon or two ago. Oh, most of those layers also probably involve a queue and if your system is busy you probably get to wait in line a lot. And if you are virtualized you can add a few more layers.
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