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Improve efficiency of attribute scanning in CopyReadAttributesCSV. 

The loop is split into two parts, inside quotes, and outside quotes, saving some instructions in both parts.

Heikki Linnakangas
This commit is contained in:
Andrew Dunstan 2008-03-08 01:16:26 +00:00
parent 9c767ad57b
commit 95c238d941
1 changed files with 65 additions and 51 deletions
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116
src/backend/commands/copy.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.295 2008/01/01 19:45:48 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.296 2008/03/08 01:16:26 adunstan Exp $
*
*-------------------------------------------------------------------------
*/
@ -2913,7 +2913,6 @@ CopyReadAttributesCSV(CopyState cstate, int maxfields, char **fieldvals)
for (;;)
{
bool found_delim = false;
bool in_quote = false;
bool saw_quote = false;
char *start_ptr;
char *end_ptr;
@ -2929,72 +2928,87 @@ CopyReadAttributesCSV(CopyState cstate, int maxfields, char **fieldvals)
start_ptr = cur_ptr;
fieldvals[fieldno] = output_ptr;
/* Scan data for field */
/* Scan data for field,
*
* The loop starts in "not quote" mode and then toggles between
* that and "in quote" mode.
* The loop exits normally if it is in "not quote" mode and a
* delimiter or line end is seen.
*/
for (;;)
{
char c;
end_ptr = cur_ptr;
if (cur_ptr >= line_end_ptr)
break;
c = *cur_ptr++;
/* unquoted field delimiter */
if (c == delimc && !in_quote)
/* Not in quote */
for (;;)
{
found_delim = true;
break;
}
/* start of quoted field (or part of field) */
if (c == quotec && !in_quote)
{
saw_quote = true;
in_quote = true;
continue;
}
/* escape within a quoted field */
if (c == escapec && in_quote)
{
/*
* peek at the next char if available, and escape it if it is
* an escape char or a quote char
*/
if (cur_ptr < line_end_ptr)
end_ptr = cur_ptr;
if (cur_ptr >= line_end_ptr)
goto endfield;
c = *cur_ptr++;
/* unquoted field delimiter */
if (c == delimc)
{
char nextc = *cur_ptr;
found_delim = true;
goto endfield;
}
/* start of quoted field (or part of field) */
if (c == quotec)
{
saw_quote = true;
break;
}
/* Add c to output string */
*output_ptr++ = c;
}
if (nextc == escapec || nextc == quotec)
/* In quote */
for (;;)
{
end_ptr = cur_ptr;
if (cur_ptr >= line_end_ptr)
ereport(ERROR,
(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
errmsg("unterminated CSV quoted field")));
c = *cur_ptr++;
/* escape within a quoted field */
if (c == escapec)
{
/*
* peek at the next char if available, and escape it if it is
* an escape char or a quote char
*/
if (cur_ptr < line_end_ptr)
{
*output_ptr++ = nextc;
cur_ptr++;
continue;
char nextc = *cur_ptr;
if (nextc == escapec || nextc == quotec)
{
*output_ptr++ = nextc;
cur_ptr++;
continue;
}
}
}
}
/*
* end of quoted field. Must do this test after testing for escape
* in case quote char and escape char are the same (which is the
* common case).
*/
if (c == quotec)
break;
/*
* end of quoted field. Must do this test after testing for escape
* in case quote char and escape char are the same (which is the
* common case).
*/
if (c == quotec && in_quote)
{
in_quote = false;
continue;
/* Add c to output string */
*output_ptr++ = c;
}
/* Add c to output string */
*output_ptr++ = c;
}
endfield:
/* Terminate attribute value in output area */
*output_ptr++ = '\0';
/* Shouldn't still be in quote mode */
if (in_quote)
ereport(ERROR,
(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
errmsg("unterminated CSV quoted field")));
/* Check whether raw input matched null marker */
input_len = end_ptr - start_ptr;
if (!saw_quote && input_len == cstate->null_print_len &&