Re: repeated pointless memmove() calls in pqReadData()

Brent Ewing <bge(at)u(dot)washington(dot)edu> writes:
> Second, I am puzzled by repeated, apparently pointless calls to memmove() in
> the function pqReadData, which is in `src/interfaces/libpq/fe-misc.c'.

Hm. That was never a problem back when we had an 8K row-size limit ;-)
but I can see that it might get to be an issue for retrieving huge rows.
Thanks for the suggestion. I've applied the attached patch to current
sources.

regards, tom lane

*** fe-misc.c~ Sat Mar 31 18:13:30 2001
--- fe-misc.c Mon May 28 11:29:51 2001
***************
*** 400,413 ****
/* Left-justify any data in the buffer to make room */
if (conn->inStart < conn->inEnd)
{
! memmove(conn->inBuffer, conn->inBuffer + conn->inStart,
! conn->inEnd - conn->inStart);
! conn->inEnd -= conn->inStart;
! conn->inCursor -= conn->inStart;
! conn->inStart = 0;
}
else
conn->inStart = conn->inCursor = conn->inEnd = 0;

/*
* If the buffer is fairly full, enlarge it. We need to be able to
--- 400,419 ----
/* Left-justify any data in the buffer to make room */
if (conn->inStart < conn->inEnd)
{
! if (conn->inStart > 0)
! {
! memmove(conn->inBuffer, conn->inBuffer + conn->inStart,
! conn->inEnd - conn->inStart);
! conn->inEnd -= conn->inStart;
! conn->inCursor -= conn->inStart;
! conn->inStart = 0;
! }
}
else
+ {
+ /* buffer is logically empty, reset it */
conn->inStart = conn->inCursor = conn->inEnd = 0;
+ }

/*
* If the buffer is fairly full, enlarge it. We need to be able to