Re: mosbench revisited

Robert Haas <robertmhaas@gmail.com> writes:
> On a straight pgbench -S test, you get four system calls per query:
> recvfrom(), lseek(), lseek(), sendto().  Adding -M prepared eliminates
> the two lseeks.

[ scratches head... ]  Two?  Is that one for the table and one for its
lone index, or are we being redundant there?

(If the query ended up being a seqscan, I'd expect a second
lseek(SEEK_END) when the executor starts up, but I gather from the other
complaints that the mosbench people were only testing simple indexscan
queries.)
        regards, tom lane