Re: Maximum PQsendQuery size?

Andreas Pflug wrote:

> I'm having trouble with PQsendQuery if sending medium sized queries.
> Everything's fine with queries up to 8190 bytes (0x1fffe), but one
> byte more will not work.
> In this case, PQsendQuery and PQconsumeInput will return ok, but
> PQisBusy stays busy. How can I get around this?
>
> Regards,
>
> Andreas
>
>
I already found a solution in pgsql/src/interfaces/libpq/fe-misc.c.

conn->outBuffer initially has 8k size. For a successful 8190 byte
execute, this contains a 'Q', the query and the terminating zero byte.
If pqPutBytes() finds avail to be too small, it will first try to
pqSendSome(), but this will not be good if the connection is nonblocking.

As a fix, the outbuffer is realloced to be big enough, before processing
continues:

        avail = Max(conn->outBufSize - conn->outCount, 0);
 >>>>>
        if (nbytes > avail && pqIsnonblocking(conn))
        {
            char *newbuf;
            conn->outBufSize = conn->outBufSize  - avail + nbytes;
            newbuf = realloc(conn->outBuffer, conn->outBufSize);
            conn->outBuffer = newbuf;
            avail = conn->outBufSize - conn->outCount;
        }
<<<<<
        remaining = Min(avail, nbytes);


pgadmin3 (to be found at
http://www.pse-consulting.de/pgadmin3/pgadmin3.zip) ist linked with this
patched libpq.


Regards,
Andreas