Re: pgsql: Our code had: if (c == '\\' &&

Bruce ­ have you tested the performance before and after?

- Luke

On 12/27/05 10:10 AM, "momjian(at)postgresql(dot)org" <momjian(at)postgresql(dot)org>
wrote:

> Log Message:
> -----------
> Our code had:
>
> if (c == '\\' && cstate->line_buf.len == 0)
>
> The problem with that is the because of the input and _output_
> buffering, cstate->line_buf.len could be zero even if we are not on the
> first character of a line. In fact, for a typical line, it is zero for
> all characters on the line. The proper solution is to introduce a
> boolean, first_char_in_line, that we set as we enter the loop and clear
> once we process a character.
>
> I have restructured the line-reading code in copy.c by:
>
> o merging the CSV/non-CSV functions into a single function
> o used macros to centralize and clarify the buffering code
> o updated comments
> o renamed client_encoding_only to encoding_embeds_ascii
> o added a high-bit test to the encoding_embeds_ascii test for
> performance
> o in CSV mode, allow a backslash followed by a non-period to
> continue being processed as a data value
>
> There should be no performance impact from this patch because it is
> functionally equivalent. If you apply the patch you will see copy.c is
> much clearer in this area now and might suggest additional
> optimizations.
>
> I have also attached a 8.1-only patch to fix the CSV \. handling bug
> with no code restructuring.
>
> Modified Files:
> --------------
> pgsql/src/backend/commands:
> copy.c (r1.255 -> r1.256)
>
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/copy.c.
> diff?r1=1.255=1.256
> <http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/copy.c.
> diff?r1=1.255&r2=1.256> )
>
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