Increase the initial size of StringInfo buffers to 1024 bytes (from 256);

likewise increase the initial size of the scanner's literal buffer to 1024
(from 128).  Instrumentation of the regression tests suggests that this
saves a useful amount of repalloc() traffic --- the number of calls occurring
during one set of tests drops from about 6900 to about 3900.  The old sizes
were chosen in the late 90's with an eye to machines much smaller than
are common today.

src/backend/lib/stringinfo.c

@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	  $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.46 2007/05/28 16:43:24 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.47 2007/08/12 20:18:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -45,7 +45,7 @@ makeStringInfo(void)
 void
 initStringInfo(StringInfo str)
 {
-	int			size = 256;		/* initial default buffer size */
+	int			size = 1024;		/* initial default buffer size */
 
 	str->data = (char *) palloc(size);
 	str->maxlen = size;

src/backend/parser/scan.l

@@ -24,7 +24,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/scan.l,v 1.139 2007/01/05 22:19:34 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/scan.l,v 1.140 2007/08/12 20:18:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -820,7 +820,7 @@ scanner_init(const char *str)
 	scanbufhandle = yy_scan_buffer(scanbuf, slen + 2);
 
 	/* initialize literal buffer to a reasonable but expansible size */
-	literalalloc = 128;
+	literalalloc = 1024;
 	literalbuf = (char *) palloc(literalalloc);
 	startlit();