diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index e27ec78..631e555 100644
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -741,7 +741,9 @@ heap_form_tuple(TupleDesc tupleDescriptor,
 	 * Allocate and zero the space needed.  Note that the tuple body and
 	 * HeapTupleData management structure are allocated in one chunk.
 	 */
-	tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + len);
+	tuple = MemoryContextAllocExtended(CurrentMemoryContext,
+									   HEAPTUPLESIZE + len,
+									   MCXT_ALLOC_HUGE | MCXT_ALLOC_ZERO);
 	tuple->t_data = td = (HeapTupleHeader) ((char *) tuple + HEAPTUPLESIZE);
 
 	/*
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 3c81906..ec5d6f1 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -385,7 +385,7 @@ ReceiveCopyBegin(CopyState cstate)
 			pq_sendint(&buf, format, 2);		/* per-column formats */
 		pq_endmessage(&buf);
 		cstate->copy_dest = COPY_NEW_FE;
-		cstate->fe_msgbuf = makeStringInfo();
+		cstate->fe_msgbuf = makeLongStringInfo();
 	}
 	else
 	{
@@ -1907,7 +1907,7 @@ CopyTo(CopyState cstate)
 	cstate->null_print_client = cstate->null_print;		/* default */
 
 	/* We use fe_msgbuf as a per-row buffer regardless of copy_dest */
-	cstate->fe_msgbuf = makeStringInfo();
+	cstate->fe_msgbuf = makeLongStringInfo();
 
 	/* Get info about the columns we need to process. */
 	cstate->out_functions = (FmgrInfo *) palloc(num_phys_attrs * sizeof(FmgrInfo));
@@ -2742,8 +2742,8 @@ BeginCopyFrom(ParseState *pstate,
 	cstate->cur_attval = NULL;
 
 	/* Set up variables to avoid per-attribute overhead. */
-	initStringInfo(&cstate->attribute_buf);
-	initStringInfo(&cstate->line_buf);
+	initLongStringInfo(&cstate->attribute_buf);
+	initLongStringInfo(&cstate->line_buf);
 	cstate->line_buf_converted = false;
 	cstate->raw_buf = (char *) palloc(RAW_BUF_SIZE + 1);
 	cstate->raw_buf_index = cstate->raw_buf_len = 0;
diff --git a/src/backend/lib/stringinfo.c b/src/backend/lib/stringinfo.c
index 7382e08..35f2eab 100644
--- a/src/backend/lib/stringinfo.c
+++ b/src/backend/lib/stringinfo.c
@@ -37,10 +37,28 @@ makeStringInfo(void)
 }
 
 /*
+ * makeLongStringInfo
+ *
+ * Same as makeStringInfo for larger strings.
+ */
+StringInfo
+makeLongStringInfo(void)
+{
+	StringInfo	res;
+
+	res = (StringInfo) palloc(sizeof(StringInfoData));
+
+	initLongStringInfo(res);
+
+	return res;
+}
+
+
+/*
  * initStringInfo
  *
  * Initialize a StringInfoData struct (with previously undefined contents)
- * to describe an empty string.
+ * to describe an empty string; don't enable long strings yet.
  */
 void
 initStringInfo(StringInfo str)
@@ -49,10 +67,23 @@ initStringInfo(StringInfo str)
 
 	str->data = (char *) palloc(size);
 	str->maxlen = size;
+	str->long_ok = false;
 	resetStringInfo(str);
 }
 
 /*
+ * initLongStringInfo
+ *
+ * As initStringInfo, plus enable long strings.
+ */
+void
+initLongStringInfo(StringInfo str)
+{
+	initStringInfo(str);
+	str->long_ok = true;
+}
+
+/*
  * resetStringInfo
  *
  * Reset the StringInfo: the data buffer remains valid, but its
@@ -142,7 +173,7 @@ appendStringInfoVA(StringInfo str, const char *fmt, va_list args)
 	/*
 	 * Return pvsnprintf's estimate of the space needed.  (Although this is
 	 * given as a size_t, we know it will fit in int because it's not more
-	 * than MaxAllocSize.)
+	 * than either MaxAllocSize or half an int's width.)
 	 */
 	return (int) nprinted;
 }
@@ -244,7 +275,16 @@ appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
 void
 enlargeStringInfo(StringInfo str, int needed)
 {
-	int			newlen;
+	Size		newlen;
+	Size		limit;
+
+	/*
+	 * Determine the upper size limit.  The fact that the StringInfo API uses
+	 * "int" everywhere limits us to int's width even for "long_ok" strings.
+	 */
+	limit = str->long_ok ?
+		(((Size) 1) << (Min(sizeof(int), sizeof(Size)) * 8 - 1)) - 1 :
+		MaxAllocSize;
 
 	/*
 	 * Guard against out-of-range "needed" values.  Without this, we can get
@@ -252,7 +292,7 @@ enlargeStringInfo(StringInfo str, int needed)
 	 */
 	if (needed < 0)				/* should not happen */
 		elog(ERROR, "invalid string enlargement request size: %d", needed);
-	if (((Size) needed) >= (MaxAllocSize - (Size) str->len))
+	if (((Size) needed) >= (limit - (Size) str->len))
 		ereport(ERROR,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 				 errmsg("out of memory"),
@@ -261,7 +301,7 @@ enlargeStringInfo(StringInfo str, int needed)
 
 	needed += str->len + 1;		/* total space required now */
 
-	/* Because of the above test, we now have needed <= MaxAllocSize */
+	/* Because of the above test, we now have needed <= limit */
 
 	if (needed <= str->maxlen)
 		return;					/* got enough space already */
@@ -276,14 +316,14 @@ enlargeStringInfo(StringInfo str, int needed)
 		newlen = 2 * newlen;
 
 	/*
-	 * Clamp to MaxAllocSize in case we went past it.  Note we are assuming
-	 * here that MaxAllocSize <= INT_MAX/2, else the above loop could
-	 * overflow.  We will still have newlen >= needed.
+	 * Clamp to the limit in case we went past it.  Note we are assuming here
+	 * that limit <= INT_MAX/2, else the above loop could overflow.  We will
+	 * still have newlen >= needed.
 	 */
-	if (newlen > (int) MaxAllocSize)
-		newlen = (int) MaxAllocSize;
+	if (newlen > limit)
+		newlen = limit;
 
-	str->data = (char *) repalloc(str->data, newlen);
+	str->data = (char *) repalloc_huge(str->data, (Size) newlen);
 
 	str->maxlen = newlen;
 }
diff --git a/src/include/lib/stringinfo.h b/src/include/lib/stringinfo.h
index f644067..f65b12e 100644
--- a/src/include/lib/stringinfo.h
+++ b/src/include/lib/stringinfo.h
@@ -30,6 +30,8 @@
  *		cursor	is initialized to zero by makeStringInfo or initStringInfo,
  *				but is not otherwise touched by the stringinfo.c routines.
  *				Some routines use it to scan through a StringInfo.
+ *		long_ok whether this StringInfo can allocate more than MaxAllocSize
+ *				bytes (but still up to 2GB).
  *-------------------------
  */
 typedef struct StringInfoData
@@ -38,6 +40,7 @@ typedef struct StringInfoData
 	int			len;
 	int			maxlen;
 	int			cursor;
+	bool		long_ok;
 } StringInfoData;
 
 typedef StringInfoData *StringInfo;
@@ -67,9 +70,12 @@ typedef StringInfoData *StringInfo;
 
 /*------------------------
  * makeStringInfo
- * Create an empty 'StringInfoData' & return a pointer to it.
+ * makeLongStringInfo
+ * Create an empty 'StringInfoData' & return a pointer to it.  The former
+ * allows up to 1 GB in size, per palloc(); the latter allows longer strings.
  */
 extern StringInfo makeStringInfo(void);
+extern StringInfo makeLongStringInfo(void);
 
 /*------------------------
  * initStringInfo
@@ -79,6 +85,12 @@ extern StringInfo makeStringInfo(void);
 extern void initStringInfo(StringInfo str);
 
 /*------------------------
+ * initLongStringInfo
+ * Same as initStringInfo but for larger strings (up to 2GB)
+ */
+extern void initLongStringInfo(StringInfo str);
+
+/*------------------------
  * resetStringInfo
  * Clears the current content of the StringInfo, if any. The
  * StringInfo remains valid.