diff --git a/src/test/mb/expected/euc_tw.out b/src/test/mb/expected/euc_tw.out
new file mode 100644
index 0000000000..c0aff468d0
--- /dev/null
+++ b/src/test/mb/expected/euc_tw.out
@@ -0,0 +1,85 @@
+QUERY: drop table ìÞÙ¸æñÕè;
+ERROR:  Relation ìÞÙ¸æñÕè Does Not Exist!
+QUERY: create table ìÞÙ¸æñÕè (ÈçäÆɱ text, ÄüƳÍñó¤ varchar, ÇâÉß varchar(16));
+QUERY: create index ìÞÙ¸æñÕèindex1 on ìÞÙ¸æñÕè using btree (ÈçäÆɱ);
+QUERY: create index ìÞÙ¸æñÕèindex2 on ìÞÙ¸æñÕè using hash (ÄüƳÍñó¤);
+QUERY: insert into ìÞÙ¸æñÕè values ('çÙæªäÆ', 'ç®ç®ÒïÊÀ', 'Æ¡A01Äî');
+QUERY: insert into ìÞÙ¸æñÕè values ('êûÝßäÆ', 'ØÂäãÈ´ÓîÄüƳ', 'ÄãB10Äã');
+QUERY: insert into ìÞÙ¸æñÕè values ('ó§ã£äÆ', 'Ó¡ÌÀϴǹȴÓîÄüƳ', 'ØíZ01Ħ');
+QUERY: vacuum ìÞÙ¸æñÕè;
+QUERY: select * from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(3 rows)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß = 'ØíZ01Ħ';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß ~* 'Øíz01Ħ';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z01_';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z%';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~ 'ç®ç®Òï[ÙìØ´ÊÀ]';
+ÈçäÆɱ|ÄüƳÍñó¤|ÇâÉß   
+------+--------+-------
+çÙæªäÆ|ç®ç®ÒïÊÀ|Æ¡A01Äî
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~* 'ç®ç®Òï[ÙìØ´ÊÀ]';
+ÈçäÆɱ|ÄüƳÍñó¤|ÇâÉß   
+------+--------+-------
+çÙæªäÆ|ç®ç®ÒïÊÀ|Æ¡A01Äî
+(1 row)
+
+QUERY: select *, character_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |length
+------+----------------+-------+------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|     3
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|     3
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|     3
+(3 rows)
+
+QUERY: select *, octet_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |octet_length
+------+----------------+-------+------------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|           6
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|           6
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|           6
+(3 rows)
+
+QUERY: select *, position('È´Óî' in ÄüƳÍñó¤) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |strpos
+------+----------------+-------+------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|     0
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|     3
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|     5
+(3 rows)
+
+QUERY: select *, substring(ÄüƳÍñó¤ from 3 for 6 ) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |substr      
+------+----------------+-------+------------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|ÒïÊÀ        
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|È´ÓîÄüƳ    
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|ϴǹȴÓîÄüƳ
+(3 rows)
+
diff --git a/src/test/mb/sql/euc_tw.sql b/src/test/mb/sql/euc_tw.sql
new file mode 100644
index 0000000000..79f3def432
--- /dev/null
+++ b/src/test/mb/sql/euc_tw.sql
@@ -0,0 +1,20 @@
+drop table ìÞÙ¸æñÕè;
+create table ìÞÙ¸æñÕè (ÈçäÆɱ text, ÄüƳÍñó¤ varchar, ÇâÉß varchar(16));
+create index ìÞÙ¸æñÕèindex1 on ìÞÙ¸æñÕè using btree (ÈçäÆɱ);
+create index ìÞÙ¸æñÕèindex2 on ìÞÙ¸æñÕè using hash (ÄüƳÍñó¤);
+insert into ìÞÙ¸æñÕè values ('çÙæªäÆ', 'ç®ç®ÒïÊÀ', 'Æ¡A01Äî');
+insert into ìÞÙ¸æñÕè values ('êûÝßäÆ', 'ØÂäãÈ´ÓîÄüƳ', 'ÄãB10Äã');
+insert into ìÞÙ¸æñÕè values ('ó§ã£äÆ', 'Ó¡ÌÀϴǹȴÓîÄüƳ', 'ØíZ01Ħ');
+vacuum ìÞÙ¸æñÕè;
+select * from ìÞÙ¸æñÕè;
+select * from ìÞÙ¸æñÕè where ÇâÉß = 'ØíZ01Ħ';
+select * from ìÞÙ¸æñÕè where ÇâÉß ~* 'Øíz01Ħ';
+select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z01_';
+select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z%';
+select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~ 'ç®ç®Òï[ÙìØ´ÊÀ]';
+select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~* 'ç®ç®Òï[ÙìØ´ÊÀ]';
+
+select *, character_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+select *, octet_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+select *, position('È´Óî' in ÄüƳÍñó¤) from ìÞÙ¸æñÕè;
+select *, substring(ÄüƳÍñó¤ from 3 for 6 ) from ìÞÙ¸æñÕè;
diff --git a/src/test/regress/expected/euc_tw.out b/src/test/regress/expected/euc_tw.out
new file mode 100644
index 0000000000..c0aff468d0
--- /dev/null
+++ b/src/test/regress/expected/euc_tw.out
@@ -0,0 +1,85 @@
+QUERY: drop table ìÞÙ¸æñÕè;
+ERROR:  Relation ìÞÙ¸æñÕè Does Not Exist!
+QUERY: create table ìÞÙ¸æñÕè (ÈçäÆɱ text, ÄüƳÍñó¤ varchar, ÇâÉß varchar(16));
+QUERY: create index ìÞÙ¸æñÕèindex1 on ìÞÙ¸æñÕè using btree (ÈçäÆɱ);
+QUERY: create index ìÞÙ¸æñÕèindex2 on ìÞÙ¸æñÕè using hash (ÄüƳÍñó¤);
+QUERY: insert into ìÞÙ¸æñÕè values ('çÙæªäÆ', 'ç®ç®ÒïÊÀ', 'Æ¡A01Äî');
+QUERY: insert into ìÞÙ¸æñÕè values ('êûÝßäÆ', 'ØÂäãÈ´ÓîÄüƳ', 'ÄãB10Äã');
+QUERY: insert into ìÞÙ¸æñÕè values ('ó§ã£äÆ', 'Ó¡ÌÀϴǹȴÓîÄüƳ', 'ØíZ01Ħ');
+QUERY: vacuum ìÞÙ¸æñÕè;
+QUERY: select * from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(3 rows)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß = 'ØíZ01Ħ';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß ~* 'Øíz01Ħ';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z01_';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z%';
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   
+------+----------------+-------
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~ 'ç®ç®Òï[ÙìØ´ÊÀ]';
+ÈçäÆɱ|ÄüƳÍñó¤|ÇâÉß   
+------+--------+-------
+çÙæªäÆ|ç®ç®ÒïÊÀ|Æ¡A01Äî
+(1 row)
+
+QUERY: select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~* 'ç®ç®Òï[ÙìØ´ÊÀ]';
+ÈçäÆɱ|ÄüƳÍñó¤|ÇâÉß   
+------+--------+-------
+çÙæªäÆ|ç®ç®ÒïÊÀ|Æ¡A01Äî
+(1 row)
+
+QUERY: select *, character_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |length
+------+----------------+-------+------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|     3
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|     3
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|     3
+(3 rows)
+
+QUERY: select *, octet_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |octet_length
+------+----------------+-------+------------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|           6
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|           6
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|           6
+(3 rows)
+
+QUERY: select *, position('È´Óî' in ÄüƳÍñó¤) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |strpos
+------+----------------+-------+------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|     0
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|     3
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|     5
+(3 rows)
+
+QUERY: select *, substring(ÄüƳÍñó¤ from 3 for 6 ) from ìÞÙ¸æñÕè;
+ÈçäÆɱ|ÄüƳÍñó¤        |ÇâÉß   |substr      
+------+----------------+-------+------------
+çÙæªäÆ|ç®ç®ÒïÊÀ        |Æ¡A01Äî|ÒïÊÀ        
+êûÝßäÆ|ØÂäãÈ´ÓîÄüƳ    |ÄãB10Äã|È´ÓîÄüƳ    
+ó§ã£äÆ|Ó¡ÌÀϴǹȴÓîÄüƳ|ØíZ01Ħ|ϴǹȴÓîÄüƳ
+(3 rows)
+
diff --git a/src/test/regress/sql/euc_tw.sql b/src/test/regress/sql/euc_tw.sql
new file mode 100644
index 0000000000..79f3def432
--- /dev/null
+++ b/src/test/regress/sql/euc_tw.sql
@@ -0,0 +1,20 @@
+drop table ìÞÙ¸æñÕè;
+create table ìÞÙ¸æñÕè (ÈçäÆɱ text, ÄüƳÍñó¤ varchar, ÇâÉß varchar(16));
+create index ìÞÙ¸æñÕèindex1 on ìÞÙ¸æñÕè using btree (ÈçäÆɱ);
+create index ìÞÙ¸æñÕèindex2 on ìÞÙ¸æñÕè using hash (ÄüƳÍñó¤);
+insert into ìÞÙ¸æñÕè values ('çÙæªäÆ', 'ç®ç®ÒïÊÀ', 'Æ¡A01Äî');
+insert into ìÞÙ¸æñÕè values ('êûÝßäÆ', 'ØÂäãÈ´ÓîÄüƳ', 'ÄãB10Äã');
+insert into ìÞÙ¸æñÕè values ('ó§ã£äÆ', 'Ó¡ÌÀϴǹȴÓîÄüƳ', 'ØíZ01Ħ');
+vacuum ìÞÙ¸æñÕè;
+select * from ìÞÙ¸æñÕè;
+select * from ìÞÙ¸æñÕè where ÇâÉß = 'ØíZ01Ħ';
+select * from ìÞÙ¸æñÕè where ÇâÉß ~* 'Øíz01Ħ';
+select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z01_';
+select * from ìÞÙ¸æñÕè where ÇâÉß like '_Z%';
+select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~ 'ç®ç®Òï[ÙìØ´ÊÀ]';
+select * from ìÞÙ¸æñÕè where ÄüƳÍñó¤ ~* 'ç®ç®Òï[ÙìØ´ÊÀ]';
+
+select *, character_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+select *, octet_length(ÈçäÆɱ) from ìÞÙ¸æñÕè;
+select *, position('È´Óî' in ÄüƳÍñó¤) from ìÞÙ¸æñÕè;
+select *, substring(ÄüƳÍñó¤ from 3 for 6 ) from ìÞÙ¸æñÕè;