diff --git a/wal2json.c b/wal2json.c
index 53a933f..a0ccf58 100644
--- a/wal2json.c
+++ b/wal2json.c
@@ -88,6 +88,7 @@ static void pg_decode_message(LogicalDecodingContext *ctx,
 
 static bool parse_table_identifier(List *qualified_tables, char separator, List **select_tables);
 static bool string_to_SelectTable(char *rawstring, char separator, List **select_tables);
+static void appendStringInfoStrings(StringInfo str, int numargs,...);
 
 void
 _PG_init(void)
@@ -391,7 +392,7 @@ pg_decode_begin_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn)
 	/* Transaction starts */
 	OutputPluginPrepareWrite(ctx, true);
 
-	appendStringInfo(ctx->out, "{%s", data->nl);
+	appendStringInfoStrings(ctx->out, 2, "{", data->nl);
 
 	if (data->include_xids)
 		appendStringInfo(ctx->out, "%s\"xid\":%s%u,%s", data->ht, data->sp, txn->xid, data->nl);
@@ -400,15 +401,15 @@ pg_decode_begin_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn)
 	{
 		char *lsn_str = DatumGetCString(DirectFunctionCall1(pg_lsn_out, txn->end_lsn));
 
-		appendStringInfo(ctx->out, "%s\"nextlsn\":%s\"%s\",%s", data->ht, data->sp, lsn_str, data->nl);
+		appendStringInfoStrings(ctx->out, 7, data->ht, "\"nextlsn\":", data->sp, "\"", lsn_str, "\"", data->nl);
 
 		pfree(lsn_str);
 	}
 
 	if (data->include_timestamp)
-		appendStringInfo(ctx->out, "%s\"timestamp\":%s\"%s\",%s", data->ht, data->sp, timestamptz_to_str(txn->commit_time), data->nl);
+		appendStringInfoStrings(ctx->out, 7, data->ht, "\"timestamp\":", data->sp, "\"", timestamptz_to_str(txn->commit_time), "\"", data->nl);
 
-	appendStringInfo(ctx->out, "%s\"change\":%s[", data->ht, data->sp);
+	appendStringInfoStrings(ctx->out, 4, data->ht, "\"change\":", data->sp, "[");
 
 	if (data->write_in_chunks)
 		OutputPluginWrite(ctx, true);
@@ -434,9 +435,9 @@ pg_decode_commit_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 
 	/* if we don't write in chunks, we need a newline here */
 	if (!data->write_in_chunks)
-		appendStringInfo(ctx->out, "%s", data->nl);
+		appendStringInfoString(ctx->out, data->nl);
 
-	appendStringInfo(ctx->out, "%s]%s}", data->ht, data->nl);
+	appendStringInfoStrings(ctx->out, 4, data->ht, "]", data->nl, "}");
 
 	OutputPluginWrite(ctx, true);
 }
@@ -478,22 +479,22 @@ tuple_to_stringinfo(LogicalDecodingContext *ctx, TupleDesc tupdesc, HeapTuple tu
 	 */
 	if (replident)
 	{
-		appendStringInfo(&colnames, "%s%s%s\"oldkeys\":%s{%s", data->ht, data->ht, data->ht, data->sp, data->nl);
-		appendStringInfo(&colnames, "%s%s%s%s\"keynames\":%s[", data->ht, data->ht, data->ht, data->ht, data->sp);
-		appendStringInfo(&coltypes, "%s%s%s%s\"keytypes\":%s[", data->ht, data->ht, data->ht, data->ht, data->sp);
+		appendStringInfoStrings(&colnames, 7, data->ht, data->ht, data->ht, "\"oldkeys\":", data->sp, "{", data->nl);
+		appendStringInfoStrings(&colnames, 7, data->ht, data->ht, data->ht, data->ht, "\"keynames\":", data->sp, "[");
+		appendStringInfoStrings(&coltypes, 7, data->ht, data->ht, data->ht, data->ht, "\"keytypes\":", data->sp, "[");
 		if (data->include_type_oids)
-			appendStringInfo(&coltypeoids, "%s%s%s%s\"keytypeoids\":%s[", data->ht, data->ht, data->ht, data->ht, data->sp);
-		appendStringInfo(&colvalues, "%s%s%s%s\"keyvalues\":%s[", data->ht, data->ht, data->ht, data->ht, data->sp);
+			appendStringInfoStrings(&coltypeoids, 7, data->ht, data->ht, data->ht, data->ht, "\"keytypeoids\":", data->sp, "[");
+		appendStringInfoStrings(&colvalues, 7, data->ht, data->ht, data->ht, data->ht, "\"keyvalues\":", data->sp, "[");
 	}
 	else
 	{
-		appendStringInfo(&colnames, "%s%s%s\"columnnames\":%s[", data->ht, data->ht, data->ht, data->sp);
-		appendStringInfo(&coltypes, "%s%s%s\"columntypes\":%s[", data->ht, data->ht, data->ht, data->sp);
+		appendStringInfoStrings(&colnames, 6, data->ht, data->ht, data->ht, "\"columnnames\":", data->sp, "[");
+		appendStringInfoStrings(&coltypes, 6, data->ht, data->ht, data->ht, "\"columntypes\":", data->sp, "[");
 		if (data->include_type_oids)
-			appendStringInfo(&coltypeoids, "%s%s%s\"columntypeoids\":%s[", data->ht, data->ht, data->ht, data->sp);
+			appendStringInfoStrings(&coltypeoids, 6, data->ht, data->ht, data->ht, "\"columntypeoids\":", data->sp, "[");
 		if (data->include_not_null)
-			appendStringInfo(&colnotnulls, "%s%s%s\"columnoptionals\":%s[", data->ht, data->ht, data->ht, data->sp);
-		appendStringInfo(&colvalues, "%s%s%s\"columnvalues\":%s[", data->ht, data->ht, data->ht, data->sp);
+			appendStringInfoStrings(&colnotnulls, 6, data->ht, data->ht, data->ht, "\"columnoptionals\":", data->sp, "[");
+		appendStringInfoStrings(&colvalues, 6, data->ht, data->ht, data->ht, "\"columnvalues\":", data->sp, "[");
 	}
 
 	/* Print column information (name, type, value) */
@@ -578,7 +579,7 @@ tuple_to_stringinfo(LogicalDecodingContext *ctx, TupleDesc tupdesc, HeapTuple tu
 		}
 
 		/* Accumulate each column info */
-		appendStringInfo(&colnames, "%s", comma);
+		appendStringInfoString(&colnames, comma);
 		escape_json(&colnames, NameStr(attr->attname));
 
 		if (data->include_types)
@@ -588,14 +589,14 @@ tuple_to_stringinfo(LogicalDecodingContext *ctx, TupleDesc tupdesc, HeapTuple tu
 				char	*type_str;
 
 				type_str = TextDatumGetCString(DirectFunctionCall2(format_type, attr->atttypid, attr->atttypmod));
-				appendStringInfo(&coltypes, "%s", comma);
+				appendStringInfoString(&coltypes, comma);
 				escape_json(&coltypes, type_str);
 				pfree(type_str);
 			}
 			else
 			{
 				Form_pg_type type_form = (Form_pg_type) GETSTRUCT(type_tuple);
-				appendStringInfo(&coltypes, "%s", comma);
+				appendStringInfoString(&coltypes, comma);
 				escape_json(&coltypes, NameStr(type_form->typname));
 			}
 
@@ -603,9 +604,9 @@ tuple_to_stringinfo(LogicalDecodingContext *ctx, TupleDesc tupdesc, HeapTuple tu
 			if (!replident && data->include_not_null)
 			{
 				if (attr->attnotnull)
-					appendStringInfo(&colnotnulls, "%sfalse", comma);
+					appendStringInfoStrings(&colnotnulls, 2, comma, "false");
 				else
-					appendStringInfo(&colnotnulls, "%strue", comma);
+					appendStringInfoStrings(&colnotnulls, 2, comma, "true");
 			}
 		}
 
@@ -616,7 +617,7 @@ tuple_to_stringinfo(LogicalDecodingContext *ctx, TupleDesc tupdesc, HeapTuple tu
 
 		if (isnull)
 		{
-			appendStringInfo(&colvalues, "%snull", comma);
+			appendStringInfoStrings(&colvalues, 2, comma, "null");
 		}
 		else
 		{
@@ -648,27 +649,27 @@ tuple_to_stringinfo(LogicalDecodingContext *ctx, TupleDesc tupdesc, HeapTuple tu
 							pg_strncasecmp(outputstr, "Infinity", 8) == 0 ||
 							pg_strncasecmp(outputstr, "-Infinity", 9) == 0)
 					{
-						appendStringInfo(&colvalues, "%snull", comma);
+						appendStringInfoStrings(&colvalues, 2, comma, "null");
 						elog(DEBUG1, "attribute \"%s\" is special: %s", NameStr(attr->attname), outputstr);
 					}
 					else if (strspn(outputstr, "0123456789+-eE.") == strlen(outputstr))
-						appendStringInfo(&colvalues, "%s%s", comma, outputstr);
+						appendStringInfoStrings(&colvalues, 2, comma, outputstr);
 					else
 						elog(ERROR, "%s is not a number", outputstr);
 					break;
 				case BOOLOID:
 					if (strcmp(outputstr, "t") == 0)
-						appendStringInfo(&colvalues, "%strue", comma);
+						appendStringInfoStrings(&colvalues, 2, comma, "true");
 					else
-						appendStringInfo(&colvalues, "%sfalse", comma);
+						appendStringInfoStrings(&colvalues, 2, comma, "false");
 					break;
 				case BYTEAOID:
-					appendStringInfo(&colvalues, "%s", comma);
+					appendStringInfoString(&colvalues, comma);
 					/* string is "\x54617069727573", start after "\x" */
 					escape_json(&colvalues, (outputstr + 2));
 					break;
 				default:
-					appendStringInfo(&colvalues, "%s", comma);
+					appendStringInfoString(&colvalues, comma);
 					escape_json(&colvalues, outputstr);
 					break;
 			}
@@ -682,27 +683,27 @@ tuple_to_stringinfo(LogicalDecodingContext *ctx, TupleDesc tupdesc, HeapTuple tu
 	/* Column info ends */
 	if (replident)
 	{
-		appendStringInfo(&colnames, "],%s", data->nl);
+		appendStringInfoStrings(&colnames, 2, "],", data->nl);
 		if (data->include_types)
-			appendStringInfo(&coltypes, "],%s", data->nl);
+			appendStringInfoStrings(&coltypes, 2, "],", data->nl);
 		if (data->include_type_oids)
-			appendStringInfo(&coltypeoids, "],%s", data->nl);
-		appendStringInfo(&colvalues, "]%s", data->nl);
-		appendStringInfo(&colvalues, "%s%s%s}%s", data->ht, data->ht, data->ht, data->nl);
+			appendStringInfoStrings(&coltypeoids, 2, "],", data->nl);
+		appendStringInfoStrings(&colvalues, 2, "]", data->nl);
+		appendStringInfoStrings(&colvalues, 5, data->ht, data->ht, data->ht, "}", data->nl);
 	}
 	else
 	{
-		appendStringInfo(&colnames, "],%s", data->nl);
+		appendStringInfoStrings(&colnames, 2, "],", data->nl);
 		if (data->include_types)
-			appendStringInfo(&coltypes, "],%s", data->nl);
+			appendStringInfoStrings(&coltypes, 2, "],", data->nl);
 		if (data->include_type_oids)
-			appendStringInfo(&coltypeoids, "],%s", data->nl);
+			appendStringInfoStrings(&coltypeoids, 2, "],", data->nl);
 		if (data->include_not_null)
-			appendStringInfo(&colnotnulls, "],%s", data->nl);
+			appendStringInfoStrings(&colnotnulls, 2, "],", data->nl);
 		if (hasreplident)
-			appendStringInfo(&colvalues, "],%s", data->nl);
+			appendStringInfoStrings(&colvalues, 2, "],", data->nl);
 		else
-			appendStringInfo(&colvalues, "]%s", data->nl);
+			appendStringInfoStrings(&colvalues, 2, "]", data->nl);
 	}
 
 	/* Print data */
@@ -891,26 +892,26 @@ pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 
 	/* if we don't write in chunks, we need a newline here */
 	if (!data->write_in_chunks)
-		appendStringInfo(ctx->out, "%s", data->nl);
+		appendStringInfoString(ctx->out, data->nl);
 
-	appendStringInfo(ctx->out, "%s%s", data->ht, data->ht);
+	appendStringInfoStrings(ctx->out, 2, data->ht, data->ht);
 
 	if (data->nr_changes > 1)
 		appendStringInfoChar(ctx->out, ',');
 
-	appendStringInfo(ctx->out, "{%s", data->nl);
+	appendStringInfoStrings(ctx->out, 2, "{", data->nl);
 
 	/* Print change kind */
 	switch (change->action)
 	{
 		case REORDER_BUFFER_CHANGE_INSERT:
-			appendStringInfo(ctx->out, "%s%s%s\"kind\":%s\"insert\",%s", data->ht, data->ht, data->ht, data->sp, data->nl);
+			appendStringInfoStrings(ctx->out, 7, data->ht, data->ht, data->ht, "\"kind\":", data->sp, "\"insert\",", data->nl);
 			break;
 		case REORDER_BUFFER_CHANGE_UPDATE:
-			appendStringInfo(ctx->out, "%s%s%s\"kind\":%s\"update\",%s", data->ht, data->ht, data->ht, data->sp, data->nl);
+			appendStringInfoStrings(ctx->out, 7, data->ht, data->ht, data->ht, "\"kind\":", data->sp, "\"update\",", data->nl);
 			break;
 		case REORDER_BUFFER_CHANGE_DELETE:
-			appendStringInfo(ctx->out, "%s%s%s\"kind\":%s\"delete\",%s", data->ht, data->ht, data->ht, data->sp, data->nl);
+			appendStringInfoStrings(ctx->out, 7, data->ht, data->ht, data->ht, "\"kind\":", data->sp, "\"delete\",", data->nl);
 			break;
 		default:
 			Assert(false);
@@ -919,13 +920,13 @@ pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	/* Print table name (possibly) qualified */
 	if (data->include_schemas)
 	{
-		appendStringInfo(ctx->out, "%s%s%s\"schema\":%s", data->ht, data->ht, data->ht, data->sp);
+		appendStringInfoStrings(ctx->out, 5, data->ht, data->ht, data->ht, "\"schema\":", data->sp);
 		escape_json(ctx->out, get_namespace_name(class_form->relnamespace));
-		appendStringInfo(ctx->out, ",%s", data->nl);
+		appendStringInfoStrings(ctx->out, 2, ",", data->nl);
 	}
-	appendStringInfo(ctx->out, "%s%s%s\"table\":%s", data->ht, data->ht, data->ht, data->sp);
+	appendStringInfoStrings(ctx->out, 5, data->ht, data->ht, data->ht, "\"table\":", data->sp);
 	escape_json(ctx->out, NameStr(class_form->relname));
-	appendStringInfo(ctx->out, ",%s", data->nl);
+	appendStringInfoStrings(ctx->out, 2, ",", data->nl);
 
 	switch (change->action)
 	{
@@ -991,7 +992,7 @@ pg_decode_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 			Assert(false);
 	}
 
-	appendStringInfo(ctx->out, "%s%s}", data->ht, data->ht);
+	appendStringInfoStrings(ctx->out, 3, data->ht, data->ht, "}");
 
 	MemoryContextSwitchTo(old);
 	MemoryContextReset(data->context);
@@ -1032,38 +1033,38 @@ pg_decode_message(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 
 	/* if we don't write in chunks, we need a newline here */
 	if (!data->write_in_chunks && transactional)
-			appendStringInfo(ctx->out, "%s", data->nl);
+			appendStringInfoString(ctx->out, data->nl);
 
 	/* build a complete JSON object for non-transactional message */
 	if (!transactional)
-		appendStringInfo(ctx->out, "{%s%s\"change\":%s[%s", data->nl, data->ht, data->sp, data->nl);
+		appendStringInfoStrings(ctx->out, 7, "{", data->nl, data->ht, "\"change\":", data->sp, "[", data->nl);
 
-	appendStringInfo(ctx->out, "%s%s", data->ht, data->ht);
+	appendStringInfoStrings(ctx->out, 2, data->ht, data->ht);
 
 	if (data->nr_changes > 1)
 		appendStringInfoChar(ctx->out, ',');
 
-	appendStringInfo(ctx->out, "{%s%s%s%s\"kind\":%s\"message\",%s", data->nl, data->ht, data->ht, data->ht, data->sp, data->nl);
+	appendStringInfoStrings(ctx->out, 9, "{", data->nl, data->ht, data->ht, data->ht, "\"kind\":", data->sp, "\"message\",", data->nl);
 
 	if (transactional)
-		appendStringInfo(ctx->out, "%s%s%s\"transactional\":%strue,%s", data->ht, data->ht, data->ht, data->sp, data->nl);
+		appendStringInfoStrings(ctx->out, 7, data->ht, data->ht, data->ht, "\"transactional\":", data->sp, "true,", data->nl);
 	else
-		appendStringInfo(ctx->out, "%s%s%s\"transactional\":%sfalse,%s", data->ht, data->ht, data->ht, data->sp, data->nl);
+		appendStringInfoStrings(ctx->out, 7, data->ht, data->ht, data->ht, "\"transactional\":", data->sp, "false,", data->nl);
 
-	appendStringInfo(ctx->out, "%s%s%s\"prefix\":%s", data->ht, data->ht, data->ht, data->sp);
+	appendStringInfoStrings(ctx->out, 5, data->ht, data->ht, data->ht, "\"prefix\":", data->sp);
 	escape_json(ctx->out, prefix);
-	appendStringInfo(ctx->out, ",%s%s%s%s\"content\":%s", data->nl, data->ht, data->ht, data->ht, data->sp);
+	appendStringInfoStrings(ctx->out, 7, ",", data->nl, data->ht, data->ht, data->ht, "\"content\":", data->sp);
 
 	content_str = (char *) palloc0((content_size + 1) * sizeof(char));
 	strncpy(content_str, content, content_size);
 	escape_json(ctx->out, content_str);
 	pfree(content_str);
 
-	appendStringInfo(ctx->out, "%s%s%s}", data->nl, data->ht, data->ht);
+	appendStringInfoStrings(ctx->out, 4, data->nl, data->ht, data->ht, "}");
 
 	/* build a complete JSON object for non-transactional message */
 	if (!transactional)
-		appendStringInfo(ctx->out, "%s%s]%s}", data->nl, data->ht, data->nl);
+		appendStringInfoStrings(ctx->out, 5, data->nl, data->ht, "]", data->nl, "}");
 
 	MemoryContextSwitchTo(old);
 	MemoryContextReset(data->context);
@@ -1218,3 +1219,20 @@ string_to_SelectTable(char *rawstring, char separator, List **select_tables)
 
 	return true;
 }
+
+static void
+appendStringInfoStrings(StringInfo str, int numargs,...)
+{
+  va_list args;
+  int i;
+
+  va_start(args, numargs);
+  for (i = 0; i < numargs; i++)
+  {
+    char* s = va_arg(args, char*);
+    if (s[0] != '\0')
+      appendStringInfoString(str, s);
+  }
+  va_end(args);
+}
+