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Make some marginal performance improvements in reportErrorPosition(), 

which turns out to be a dominant part of the runtime in scenarios
involving lots of parse-time warnings (such as Stephen Frost's example
of an INSERT with a lot of backslash-containing strings).  There's not
a whole lot we can do about the character-at-a-time scanning, but we
can at least avoid traversing the query twice.
This commit is contained in:
Tom Lane 2006-10-01 22:25:48 +00:00
parent 8e4fe3ba1e
commit db2dcf58be
1 changed files with 86 additions and 66 deletions
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152
src/interfaces/libpq/fe-protocol3.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/interfaces/libpq/fe-protocol3.c,v 1.27 2006/08/18 19:52:39 tgl Exp $
* $PostgreSQL: pgsql/src/interfaces/libpq/fe-protocol3.c,v 1.28 2006/10/01 22:25:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -883,10 +883,9 @@ reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
#define MIN_RIGHT_CUT 10 /* try to keep this far away from EOL */
char *wquery;
int clen,
slen,
int slen,
cno,
i,
w,
*qidx,
*scridx,
qoffset,
@ -894,9 +893,15 @@ reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
ibeg,
iend,
loc_line;
bool beg_trunc,
bool mb_encoding,
beg_trunc,
end_trunc;
/* Convert loc from 1-based to 0-based; no-op if out of range */
loc--;
if (loc < 0)
return;
/* Need a writable copy of the query */
wquery = strdup(query);
if (wquery == NULL)
@ -905,13 +910,13 @@ reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
/*
* Each character might occupy multiple physical bytes in the string, and
* in some Far Eastern character sets it might take more than one screen
* column as well. We compute the starting byte offset and starting
* column as well. We compute the starting byte offset and starting
* screen column of each logical character, and store these in qidx[] and
* scridx[] respectively.
*/
/* we need a safe allocation size... */
slen = strlen(query) + 1;
slen = strlen(wquery) + 1;
qidx = (int *) malloc(slen * sizeof(int));
if (qidx == NULL)
@ -927,79 +932,93 @@ reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
return;
}
/* We can optimize a bit if it's a single-byte encoding */
mb_encoding = (pg_encoding_max_length(encoding) != 1);
/*
* Within the scanning loop, cno is the current character's logical number,
* qoffset is its offset in wquery, and scroffset is its starting logical
* screen column (all indexed from 0). "loc" is the logical character
* number of the error location. We scan to determine loc_line (the
* 1-based line number containing loc) and ibeg/iend (first character
* number and last+1 character number of the line containing loc).
* Note that qidx[] and scridx[] are filled only as far as iend.
*/
qoffset = 0;
scroffset = 0;
for (i = 0; query[qoffset] != '\0'; i++)
{
qidx[i] = qoffset;
scridx[i] = scroffset;
w = pg_encoding_dsplen(encoding, &query[qoffset]);
/* treat control chars as width 1; see tab hack below */
if (w <= 0)
w = 1;
scroffset += w;
qoffset += pg_encoding_mblen(encoding, &query[qoffset]);
}
qidx[i] = qoffset;
scridx[i] = scroffset;
clen = i;
loc_line = 1;
ibeg = 0;
iend = -1; /* -1 means not set yet */
/* convert loc to zero-based offset in qidx/scridx arrays */
loc--;
/* do we have something to show? */
if (loc >= 0 && loc <= clen)
for (cno = 0; wquery[qoffset] != '\0'; cno++)
{
/* input line number of our syntax error. */
loc_line = 1;
/* first included char of extract. */
ibeg = 0;
/* last-plus-1 included char of extract. */
iend = clen;
char ch = wquery[qoffset];
qidx[cno] = qoffset;
scridx[cno] = scroffset;
/*
* Replace tabs with spaces in the writable copy. (Later we might
* want to think about coping with their variable screen width, but
* not today.)
*
* Extract line number and begin and end indexes of line containing
* error location. There will not be any newlines or carriage returns
* in the selected extract.
*/
for (i = 0; i < clen; i++)
if (ch == '\t')
wquery[qoffset] = ' ';
/*
* If end-of-line, count lines and mark positions. Each \r or \n counts
* as a line except when \r \n appear together.
*/
else if (ch == '\r' || ch == '\n')
{
/* character length must be 1 or it's not ASCII */
if ((qidx[i + 1] - qidx[i]) == 1)
if (cno < loc)
{
if (wquery[qidx[i]] == '\t')
wquery[qidx[i]] = ' ';
else if (wquery[qidx[i]] == '\r' || wquery[qidx[i]] == '\n')
{
if (i < loc)
{
/*
* count lines before loc. Each \r or \n counts
* as a line except when \r \n appear together.
*/
if (wquery[qidx[i]] == '\r' ||
i == 0 ||
(qidx[i] - qidx[i - 1]) != 1 ||
wquery[qidx[i - 1]] != '\r')
loc_line++;
/* extract beginning = last line start before loc. */
ibeg = i + 1;
}
else
{
/* set extract end. */
iend = i;
/* done scanning. */
break;
}
}
if (ch == '\r' ||
cno == 0 ||
wquery[qidx[cno - 1]] != '\r')
loc_line++;
/* extract beginning = last line start before loc. */
ibeg = cno + 1;
}
else
{
/* set extract end. */
iend = cno;
/* done scanning. */
break;
}
}
/* Advance */
if (mb_encoding)
{
int w;
w = pg_encoding_dsplen(encoding, &wquery[qoffset]);
/* treat any non-tab control chars as width 1 */
if (w <= 0)
w = 1;
scroffset += w;
qoffset += pg_encoding_mblen(encoding, &wquery[qoffset]);
}
else
{
/* We assume wide chars only exist in multibyte encodings */
scroffset++;
qoffset++;
}
}
/* Fix up if we didn't find an end-of-line after loc */
if (iend < 0)
{
iend = cno; /* query length in chars, +1 */
qidx[iend] = qoffset;
scridx[iend] = scroffset;
}
/* Print only if loc is within computed query length */
if (loc <= cno)
{
/* If the line extracted is too long, we truncate it. */
beg_trunc = false;
end_trunc = false;
@ -1050,7 +1069,8 @@ reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
scroffset = 0;
for (; i < msg->len; i += pg_encoding_mblen(encoding, &msg->data[i]))
{
w = pg_encoding_dsplen(encoding, &msg->data[i]);
int w = pg_encoding_dsplen(encoding, &msg->data[i]);
if (w <= 0)
w = 1;
scroffset += w;