diff --git a/src/backend/libpq/pqformat.c b/src/backend/libpq/pqformat.c
index a6f990c..0fc8c3f 100644
--- a/src/backend/libpq/pqformat.c
+++ b/src/backend/libpq/pqformat.c
@@ -328,11 +328,8 @@ void
 pq_begintypsend(StringInfo buf)
 {
 	initStringInfo(buf);
-	/* Reserve four bytes for the bytea length word */
-	appendStringInfoCharMacro(buf, '\0');
-	appendStringInfoCharMacro(buf, '\0');
-	appendStringInfoCharMacro(buf, '\0');
-	appendStringInfoCharMacro(buf, '\0');
+	/* Reserve four bytes for the bytea length word; contents not important */
+	appendStringInfoSpaces(buf, 4);
 }
 
 /* --------------------------------
diff --git a/src/common/stringinfo.c b/src/common/stringinfo.c
index 0badc46..8f8bb0d 100644
--- a/src/common/stringinfo.c
+++ b/src/common/stringinfo.c
@@ -207,43 +207,21 @@ appendStringInfoSpaces(StringInfo str, int count)
 {
 	if (count > 0)
 	{
+		char	   *ptr;
+
 		/* Make more room if needed */
 		enlargeStringInfo(str, count);
 
 		/* OK, append the spaces */
+		ptr = str->data + str->len;
+		str->len += count;
 		while (--count >= 0)
-			str->data[str->len++] = ' ';
-		str->data[str->len] = '\0';
+			*ptr++ = ' ';
+		*ptr = '\0';
 	}
 }
 
 /*
- * appendBinaryStringInfo
- *
- * Append arbitrary binary data to a StringInfo, allocating more space
- * if necessary. Ensures that a trailing null byte is present.
- */
-void
-appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
-{
-	Assert(str != NULL);
-
-	/* Make more room if needed */
-	enlargeStringInfo(str, datalen);
-
-	/* OK, append the data */
-	memcpy(str->data + str->len, data, datalen);
-	str->len += datalen;
-
-	/*
-	 * Keep a trailing null in place, even though it's probably useless for
-	 * binary data.  (Some callers are dealing with text but call this because
-	 * their input isn't null-terminated.)
-	 */
-	str->data[str->len] = '\0';
-}
-
-/*
  * appendBinaryStringInfoNT
  *
  * Append arbitrary binary data to a StringInfo, allocating more space
@@ -263,7 +241,7 @@ appendBinaryStringInfoNT(StringInfo str, const char *data, int datalen)
 }
 
 /*
- * enlargeStringInfo
+ * enlargeStringInfo_OOL
  *
  * Make sure there is enough space for 'needed' more bytes
  * ('needed' does not include the terminating null).
@@ -274,13 +252,16 @@ appendBinaryStringInfoNT(StringInfo str, const char *data, int datalen)
  * can save some palloc overhead by enlarging the buffer before starting
  * to store data in it.
  *
+ * We normally reach here only if enlargement is needed, since callers
+ * go through the inline function which doesn't call this otherwise.
+ *
  * NB: In the backend, because we use repalloc() to enlarge the buffer, the
  * string buffer will remain allocated in the same memory context that was
  * current when initStringInfo was called, even if another context is now
  * current.  This is the desired and indeed critical behavior!
  */
 void
-enlargeStringInfo(StringInfo str, int needed)
+enlargeStringInfo_OOL(StringInfo str, int needed)
 {
 	int			newlen;
 
diff --git a/src/include/lib/stringinfo.h b/src/include/lib/stringinfo.h
index 5a2a3db..30ba826 100644
--- a/src/include/lib/stringinfo.h
+++ b/src/include/lib/stringinfo.h
@@ -87,6 +87,25 @@ extern void initStringInfo(StringInfo str);
 extern void resetStringInfo(StringInfo str);
 
 /*------------------------
+ * enlargeStringInfo
+ * Make sure a StringInfo's buffer can hold at least 'needed' more bytes
+ * ('needed' does not include the terminating null).
+ * The inlined code eliminates the common case where no work is needed.
+ */
+extern void enlargeStringInfo_OOL(StringInfo str, int needed);
+
+static inline void
+enlargeStringInfo(StringInfo str, int needed)
+{
+	/*
+	 * Do the test in unsigned arithmetic so that if "needed" is negative,
+	 * we'll go to the out-of-line code which will error out.
+	 */
+	if ((unsigned) needed >= (unsigned) (str->maxlen - str->len))
+		enlargeStringInfo_OOL(str, needed);
+}
+
+/*------------------------
  * appendStringInfo
  * Format text data under the control of fmt (an sprintf-style format string)
  * and append it to whatever is already in str.  More space is allocated
@@ -139,10 +158,27 @@ extern void appendStringInfoSpaces(StringInfo str, int count);
 /*------------------------
  * appendBinaryStringInfo
  * Append arbitrary binary data to a StringInfo, allocating more space
- * if necessary.
+ * if necessary.  Ensures that a trailing null byte is present.
  */
-extern void appendBinaryStringInfo(StringInfo str,
-								   const char *data, int datalen);
+static inline void
+appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
+{
+	Assert(str != NULL);
+
+	/* Make more room if needed */
+	enlargeStringInfo(str, datalen);
+
+	/* OK, append the data */
+	memcpy(str->data + str->len, data, datalen);
+	str->len += datalen;
+
+	/*
+	 * Keep a trailing null in place, even though it's probably useless for
+	 * binary data.  (Some callers are dealing with text but call this because
+	 * their input isn't null-terminated.)
+	 */
+	str->data[str->len] = '\0';
+}
 
 /*------------------------
  * appendBinaryStringInfoNT
@@ -152,10 +188,4 @@ extern void appendBinaryStringInfo(StringInfo str,
 extern void appendBinaryStringInfoNT(StringInfo str,
 									 const char *data, int datalen);
 
-/*------------------------
- * enlargeStringInfo
- * Make sure a StringInfo's buffer can hold at least 'needed' more bytes.
- */
-extern void enlargeStringInfo(StringInfo str, int needed);
-
 #endif							/* STRINGINFO_H */