fix Core dump when execute 'select * from hawq_toolkit.__hawq_log_master_ext;' on macOS
@@ -147,7 +147,7 @@ typedef struct extvar_t
char GP_XID[TMGIDSIZE]; /* global transaction id */
char GP_CID[10]; /* command id */
char GP_SN[10]; /* scan number */
- char GP_SEGMENT_ID[6]; /*segments content id*/
+ char GP_SEGMENT_ID[7]; /*segments content id*/
char GP_SEG_PORT[10];
char GP_SESSION_ID[10]; /* session id */
char GP_SEGMENT_COUNT[6]; /* total number of (primary) segs in the system */
