diff --git a/contrib/test_decoding/expected/ddl.out b/contrib/test_decoding/expected/ddl.out
index 2bd28e6d15e..2c999fd3eb7 100644
--- a/contrib/test_decoding/expected/ddl.out
+++ b/contrib/test_decoding/expected/ddl.out
@@ -17,8 +17,8 @@ HINT:  Replication slot names may only contain lower case letters, numbers, and
 SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', 'frakbar');
 ERROR:  could not parse value "frakbar" for parameter "include-xids"
 CONTEXT:  slot "regression_slot", output plugin "test_decoding", in the startup callback
-SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'nonexistant-option', 'frakbar');
-ERROR:  option "nonexistant-option" = "frakbar" is unknown
+SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'nonexistent-option', 'frakbar');
+ERROR:  option "nonexistent-option" = "frakbar" is unknown
 CONTEXT:  slot "regression_slot", output plugin "test_decoding", in the startup callback
 SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', 'frakbar');
 ERROR:  could not parse value "frakbar" for parameter "include-xids"
diff --git a/contrib/test_decoding/sql/ddl.sql b/contrib/test_decoding/sql/ddl.sql
index a55086443ca..856495c9526 100644
--- a/contrib/test_decoding/sql/ddl.sql
+++ b/contrib/test_decoding/sql/ddl.sql
@@ -9,7 +9,7 @@ SELECT 'init' FROM pg_create_logical_replication_slot('Invalid Name', 'test_deco
 
 -- fail twice because of an invalid parameter values
 SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', 'frakbar');
-SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'nonexistant-option', 'frakbar');
+SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'nonexistent-option', 'frakbar');
 SELECT 'init' FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', 'frakbar');
 
 -- succeed once
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index ea6283c51a6..5afbc51ed71 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3340,22 +3340,22 @@ command_fails_like(
 # Test dumping a non-existent schema, table, and patterns with --strict-names
 
 command_fails_like(
-	[ 'pg_dump', '-p', "$port", '-n', 'nonexistant' ],
+	[ 'pg_dump', '-p', "$port", '-n', 'nonexistent' ],
 	qr/\Qpg_dump: error: no matching schemas were found\E/,
 	'dumping a non-existent schema');
 
 command_fails_like(
-	[ 'pg_dump', '-p', "$port", '-t', 'nonexistant' ],
+	[ 'pg_dump', '-p', "$port", '-t', 'nonexistent' ],
 	qr/\Qpg_dump: error: no matching tables were found\E/,
 	'dumping a non-existent table');
 
 command_fails_like(
-	[ 'pg_dump', '-p', "$port", '--strict-names', '-n', 'nonexistant*' ],
+	[ 'pg_dump', '-p', "$port", '--strict-names', '-n', 'nonexistent*' ],
 	qr/\Qpg_dump: error: no matching schemas were found for pattern\E/,
 	'no matching schemas');
 
 command_fails_like(
-	[ 'pg_dump', '-p', "$port", '--strict-names', '-t', 'nonexistant*' ],
+	[ 'pg_dump', '-p', "$port", '--strict-names', '-t', 'nonexistent*' ],
 	qr/\Qpg_dump: error: no matching tables were found for pattern\E/,
 	'no matching tables');
 
diff --git a/src/interfaces/ecpg/test/connect/test1.pgc b/src/interfaces/ecpg/test/connect/test1.pgc
index 101b806d5ba..82cdfb8fc56 100644
--- a/src/interfaces/ecpg/test/connect/test1.pgc
+++ b/src/interfaces/ecpg/test/connect/test1.pgc
@@ -50,7 +50,7 @@ exec sql end declare section;
 	exec sql disconnect;
 
 	/* wrong db */
-	exec sql connect to tcp:postgresql://localhost/nonexistant user regress_ecpg_user1 identified by connectpw;
+	exec sql connect to tcp:postgresql://localhost/nonexistent user regress_ecpg_user1 identified by connectpw;
 	exec sql disconnect;
 
 	/* wrong port */
diff --git a/src/interfaces/ecpg/test/connect/test5.pgc b/src/interfaces/ecpg/test/connect/test5.pgc
index 53b86556b15..2e34ab84fc6 100644
--- a/src/interfaces/ecpg/test/connect/test5.pgc
+++ b/src/interfaces/ecpg/test/connect/test5.pgc
@@ -70,7 +70,7 @@ exec sql end declare section;
 	exec sql disconnect main;
 
 	/* not connected */
-	exec sql disconnect nonexistant;
+	exec sql disconnect nonexistent;
 
 	return 0;
 }
diff --git a/src/interfaces/ecpg/test/expected/connect-test1-minGW32.stderr b/src/interfaces/ecpg/test/expected/connect-test1-minGW32.stderr
index 50a6785a02f..b334537b600 100644
--- a/src/interfaces/ecpg/test/expected/connect-test1-minGW32.stderr
+++ b/src/interfaces/ecpg/test/expected/connect-test1-minGW32.stderr
@@ -52,14 +52,14 @@
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_finish: connection ecpg2_regression closed
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ECPGconnect: opening database nonexistant on localhost port <DEFAULT>  for user regress_ecpg_user1
+[NO_PID]: ECPGconnect: opening database nonexistent on localhost port <DEFAULT>  for user regress_ecpg_user1
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ECPGconnect: could not open database: FATAL:  database "nonexistant" does not exist
+[NO_PID]: ECPGconnect: could not open database: FATAL:  database "nonexistent" does not exist
 
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_finish: connection nonexistant closed
+[NO_PID]: ecpg_finish: connection nonexistent closed
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlcode -402 on line 53: could not connect to database "nonexistant" on line 53
+[NO_PID]: raising sqlcode -402 on line 53: could not connect to database "nonexistent" on line 53
 [NO_PID]: sqlca: code: -402, state: 08001
 [NO_PID]: raising sqlcode -220 on line 54: connection "CURRENT" does not exist on line 54
 [NO_PID]: sqlca: code: -220, state: 08003
diff --git a/src/interfaces/ecpg/test/expected/connect-test1.c b/src/interfaces/ecpg/test/expected/connect-test1.c
index 98b7e717c72..894273339cd 100644
--- a/src/interfaces/ecpg/test/expected/connect-test1.c
+++ b/src/interfaces/ecpg/test/expected/connect-test1.c
@@ -101,7 +101,7 @@ main(void)
 
 
 	/* wrong db */
-	{ ECPGconnect(__LINE__, 0, "tcp:postgresql://localhost/nonexistant" , "regress_ecpg_user1" , "connectpw" , NULL, 0); }
+	{ ECPGconnect(__LINE__, 0, "tcp:postgresql://localhost/nonexistent" , "regress_ecpg_user1" , "connectpw" , NULL, 0); }
 #line 53 "test1.pgc"
 
 	{ ECPGdisconnect(__LINE__, "CURRENT");}
diff --git a/src/interfaces/ecpg/test/expected/connect-test1.stderr b/src/interfaces/ecpg/test/expected/connect-test1.stderr
index ad806a02251..c5cbf749efe 100644
--- a/src/interfaces/ecpg/test/expected/connect-test1.stderr
+++ b/src/interfaces/ecpg/test/expected/connect-test1.stderr
@@ -52,14 +52,14 @@
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_finish: connection ecpg2_regression closed
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ECPGconnect: opening database nonexistant on localhost port <DEFAULT>  for user regress_ecpg_user1
+[NO_PID]: ECPGconnect: opening database nonexistent on localhost port <DEFAULT>  for user regress_ecpg_user1
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ECPGconnect: could not open database: FATAL:  database "nonexistant" does not exist
+[NO_PID]: ECPGconnect: could not open database: FATAL:  database "nonexistent" does not exist
 
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_finish: connection nonexistant closed
+[NO_PID]: ecpg_finish: connection nonexistent closed
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlcode -402 on line 53: could not connect to database "nonexistant" on line 53
+[NO_PID]: raising sqlcode -402 on line 53: could not connect to database "nonexistent" on line 53
 [NO_PID]: sqlca: code: -402, state: 08001
 [NO_PID]: raising sqlcode -220 on line 54: connection "CURRENT" does not exist on line 54
 [NO_PID]: sqlca: code: -220, state: 08003
diff --git a/src/interfaces/ecpg/test/expected/connect-test5.c b/src/interfaces/ecpg/test/expected/connect-test5.c
index 4b6569e7633..b44104854da 100644
--- a/src/interfaces/ecpg/test/expected/connect-test5.c
+++ b/src/interfaces/ecpg/test/expected/connect-test5.c
@@ -154,7 +154,7 @@ main(void)
 
 
 	/* not connected */
-	{ ECPGdisconnect(__LINE__, "nonexistant");}
+	{ ECPGdisconnect(__LINE__, "nonexistent");}
 #line 73 "test5.pgc"
 
 
diff --git a/src/interfaces/ecpg/test/expected/connect-test5.stderr b/src/interfaces/ecpg/test/expected/connect-test5.stderr
index a797fd95d96..cefdb0739e5 100644
--- a/src/interfaces/ecpg/test/expected/connect-test5.stderr
+++ b/src/interfaces/ecpg/test/expected/connect-test5.stderr
@@ -88,5 +88,5 @@
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_finish: connection main closed
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlcode -220 on line 73: connection "nonexistant" does not exist on line 73
+[NO_PID]: raising sqlcode -220 on line 73: connection "nonexistent" does not exist on line 73
 [NO_PID]: sqlca: code: -220, state: 08003
diff --git a/src/interfaces/ecpg/test/expected/preproc-whenever.c b/src/interfaces/ecpg/test/expected/preproc-whenever.c
index 332ef85b10a..861d84f1fe7 100644
--- a/src/interfaces/ecpg/test/expected/preproc-whenever.c
+++ b/src/interfaces/ecpg/test/expected/preproc-whenever.c
@@ -103,7 +103,7 @@ if (sqlca.sqlcode < 0) sqlprint();}
 #line 37 "whenever.pgc"
 
 
-	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistant", ECPGt_EOIT, 
+	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistent", ECPGt_EOIT, 
 	ECPGt_int,&(i),(long)1,(long)1,sizeof(int), 
 	ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);
 #line 39 "whenever.pgc"
@@ -127,7 +127,7 @@ if (sqlca.sqlcode < 0) sqlprint();}
 	/* exec sql whenever sqlerror  do print ( \"select\" ) ; */
 #line 42 "whenever.pgc"
 
-	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistant", ECPGt_EOIT, 
+	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistent", ECPGt_EOIT, 
 	ECPGt_int,&(i),(long)1,(long)1,sizeof(int), 
 	ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);
 #line 43 "whenever.pgc"
@@ -151,7 +151,7 @@ if (sqlca.sqlcode < 0) print ( "select" );}
 	/* exec sql whenever sqlerror  call print2 ( ) ; */
 #line 46 "whenever.pgc"
 
-	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistant", ECPGt_EOIT, 
+	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistent", ECPGt_EOIT, 
 	ECPGt_int,&(i),(long)1,(long)1,sizeof(int), 
 	ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);
 #line 47 "whenever.pgc"
@@ -175,7 +175,7 @@ if (sqlca.sqlcode < 0) print2 ( );}
 	/* exec sql whenever sqlerror  continue ; */
 #line 50 "whenever.pgc"
 
-	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistant", ECPGt_EOIT, 
+	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistent", ECPGt_EOIT, 
 	ECPGt_int,&(i),(long)1,(long)1,sizeof(int), 
 	ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);
 #line 51 "whenever.pgc"
@@ -193,7 +193,7 @@ if (sqlca.sqlwarn[0] == 'W') warn ( );}
 	/* exec sql whenever sqlerror  goto  error ; */
 #line 54 "whenever.pgc"
 
-	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistant", ECPGt_EOIT, 
+	{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select * from nonexistent", ECPGt_EOIT, 
 	ECPGt_int,&(i),(long)1,(long)1,sizeof(int), 
 	ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);
 #line 55 "whenever.pgc"
diff --git a/src/interfaces/ecpg/test/expected/preproc-whenever.stderr b/src/interfaces/ecpg/test/expected/preproc-whenever.stderr
index e5c8fc239b2..03e94a6241b 100644
--- a/src/interfaces/ecpg/test/expected/preproc-whenever.stderr
+++ b/src/interfaces/ecpg/test/expected/preproc-whenever.stderr
@@ -27,68 +27,68 @@
 Warning: At least one column was truncated
 [NO_PID]: ECPGtrans on line 37: action "rollback"; connection "ecpg1_regression"
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_execute on line 39: query: select * from nonexistant; with 0 parameter(s) on connection ecpg1_regression
+[NO_PID]: ecpg_execute on line 39: query: select * from nonexistent; with 0 parameter(s) on connection ecpg1_regression
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_execute on line 39: using PQexec
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_check_PQresult on line 39: bad response - ERROR:  relation "nonexistant" does not exist
-LINE 1: select * from nonexistant
+[NO_PID]: ecpg_check_PQresult on line 39: bad response - ERROR:  relation "nonexistent" does not exist
+LINE 1: select * from nonexistent
                       ^
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistant" does not exist on line 39
+[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistent" does not exist on line 39
 [NO_PID]: sqlca: code: -400, state: 42P01
-SQL error: relation "nonexistant" does not exist on line 39
+SQL error: relation "nonexistent" does not exist on line 39
 [NO_PID]: ECPGtrans on line 40: action "rollback"; connection "ecpg1_regression"
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_execute on line 43: query: select * from nonexistant; with 0 parameter(s) on connection ecpg1_regression
+[NO_PID]: ecpg_execute on line 43: query: select * from nonexistent; with 0 parameter(s) on connection ecpg1_regression
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_execute on line 43: using PQexec
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_check_PQresult on line 43: bad response - ERROR:  relation "nonexistant" does not exist
-LINE 1: select * from nonexistant
+[NO_PID]: ecpg_check_PQresult on line 43: bad response - ERROR:  relation "nonexistent" does not exist
+LINE 1: select * from nonexistent
                       ^
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistant" does not exist on line 43
+[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistent" does not exist on line 43
 [NO_PID]: sqlca: code: -400, state: 42P01
 Error in statement 'select':
-SQL error: relation "nonexistant" does not exist on line 43
+SQL error: relation "nonexistent" does not exist on line 43
 [NO_PID]: ECPGtrans on line 44: action "rollback"; connection "ecpg1_regression"
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_execute on line 47: query: select * from nonexistant; with 0 parameter(s) on connection ecpg1_regression
+[NO_PID]: ecpg_execute on line 47: query: select * from nonexistent; with 0 parameter(s) on connection ecpg1_regression
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_execute on line 47: using PQexec
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_check_PQresult on line 47: bad response - ERROR:  relation "nonexistant" does not exist
-LINE 1: select * from nonexistant
+[NO_PID]: ecpg_check_PQresult on line 47: bad response - ERROR:  relation "nonexistent" does not exist
+LINE 1: select * from nonexistent
                       ^
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistant" does not exist on line 47
+[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistent" does not exist on line 47
 [NO_PID]: sqlca: code: -400, state: 42P01
 Found another error
-SQL error: relation "nonexistant" does not exist on line 47
+SQL error: relation "nonexistent" does not exist on line 47
 [NO_PID]: ECPGtrans on line 48: action "rollback"; connection "ecpg1_regression"
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_execute on line 51: query: select * from nonexistant; with 0 parameter(s) on connection ecpg1_regression
+[NO_PID]: ecpg_execute on line 51: query: select * from nonexistent; with 0 parameter(s) on connection ecpg1_regression
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_execute on line 51: using PQexec
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_check_PQresult on line 51: bad response - ERROR:  relation "nonexistant" does not exist
-LINE 1: select * from nonexistant
+[NO_PID]: ecpg_check_PQresult on line 51: bad response - ERROR:  relation "nonexistent" does not exist
+LINE 1: select * from nonexistent
                       ^
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistant" does not exist on line 51
+[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistent" does not exist on line 51
 [NO_PID]: sqlca: code: -400, state: 42P01
 [NO_PID]: ECPGtrans on line 52: action "rollback"; connection "ecpg1_regression"
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_execute on line 55: query: select * from nonexistant; with 0 parameter(s) on connection ecpg1_regression
+[NO_PID]: ecpg_execute on line 55: query: select * from nonexistent; with 0 parameter(s) on connection ecpg1_regression
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_execute on line 55: using PQexec
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_check_PQresult on line 55: bad response - ERROR:  relation "nonexistant" does not exist
-LINE 1: select * from nonexistant
+[NO_PID]: ecpg_check_PQresult on line 55: bad response - ERROR:  relation "nonexistent" does not exist
+LINE 1: select * from nonexistent
                       ^
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistant" does not exist on line 55
+[NO_PID]: raising sqlstate 42P01 (sqlcode -400): relation "nonexistent" does not exist on line 55
 [NO_PID]: sqlca: code: -400, state: 42P01
 [NO_PID]: ECPGtrans on line 59: action "rollback"; connection "ecpg1_regression"
 [NO_PID]: sqlca: code: 0, state: 00000
diff --git a/src/interfaces/ecpg/test/preproc/whenever.pgc b/src/interfaces/ecpg/test/preproc/whenever.pgc
index 14cf571e6ae..6090e5fbd5a 100644
--- a/src/interfaces/ecpg/test/preproc/whenever.pgc
+++ b/src/interfaces/ecpg/test/preproc/whenever.pgc
@@ -36,23 +36,23 @@ int main(void)
 	exec sql select * into :i, :c from test;
 	exec sql rollback;
 
-	exec sql select * into :i from nonexistant;
+	exec sql select * into :i from nonexistent;
 	exec sql rollback;
 
 	exec sql whenever sqlerror do print("select");
-	exec sql select * into :i from nonexistant;
+	exec sql select * into :i from nonexistent;
 	exec sql rollback;
 
 	exec sql whenever sqlerror call print2();
-	exec sql select * into :i from nonexistant;
+	exec sql select * into :i from nonexistent;
 	exec sql rollback;
 
 	exec sql whenever sqlerror continue;
-	exec sql select * into :i from nonexistant;
+	exec sql select * into :i from nonexistent;
 	exec sql rollback;
 
 	exec sql whenever sqlerror goto error;
-	exec sql select * into :i from nonexistant;
+	exec sql select * into :i from nonexistent;
 	printf("Should not be reachable\n");
 
 	error:
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index d795eaa59c7..cedc7c689a7 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1349,7 +1349,7 @@ delete from atacc1;
 -- try dropping a non-existent column, should fail
 alter table atacc1 drop bar;
 ERROR:  column "bar" of relation "atacc1" does not exist
--- try removing an oid column, should succeed (as it's nonexistant)
+-- try removing an oid column, should succeed (as it's nonexistent)
 alter table atacc1 SET WITHOUT OIDS;
 -- try adding an oid column, should fail (not supported)
 alter table atacc1 SET WITH OIDS;
@@ -3432,8 +3432,8 @@ LINE 1: ...list_parted ATTACH PARTITION fail_part FOR VALUES FROM (1) T...
                                                              ^
 DROP TABLE fail_part;
 -- check that the table being attached exists
-ALTER TABLE list_parted ATTACH PARTITION nonexistant FOR VALUES IN (1);
-ERROR:  relation "nonexistant" does not exist
+ALTER TABLE list_parted ATTACH PARTITION nonexistent FOR VALUES IN (1);
+ERROR:  relation "nonexistent" does not exist
 -- check ownership of the source table
 CREATE ROLE regress_test_me;
 CREATE ROLE regress_test_not_me;
diff --git a/src/test/regress/expected/create_am.out b/src/test/regress/expected/create_am.out
index f6d5c97cded..84da403afc5 100644
--- a/src/test/regress/expected/create_am.out
+++ b/src/test/regress/expected/create_am.out
@@ -111,7 +111,7 @@ NOTICE:  drop cascades to index grect2ind2
 SET default_table_access_method = '';
 ERROR:  invalid value for parameter "default_table_access_method": ""
 DETAIL:  default_table_access_method cannot be empty.
--- prevent nonexistant values
+-- prevent nonexistent values
 SET default_table_access_method = 'I do not exist AM';
 ERROR:  invalid value for parameter "default_table_access_method": "I do not exist AM"
 DETAIL:  Table access method "I do not exist AM" does not exist.
@@ -274,7 +274,7 @@ ORDER BY 3, 1, 2;
 
 -- don't want to keep those tables, nor the default
 ROLLBACK;
--- Third, check that we can neither create a table using a nonexistant
+-- Third, check that we can neither create a table using a nonexistent
 -- AM, nor using an index AM
 CREATE TABLE i_am_a_failure() USING "";
 ERROR:  zero-length delimited identifier at or near """"
diff --git a/src/test/regress/expected/rowtypes.out b/src/test/regress/expected/rowtypes.out
index ffccaa5c9d6..a272305eb55 100644
--- a/src/test/regress/expected/rowtypes.out
+++ b/src/test/regress/expected/rowtypes.out
@@ -1197,9 +1197,9 @@ ERROR:  column "ctid" not found in data type compositetable
 LINE 1: SELECT (d).ctid FROM (SELECT compositetable AS d FROM compos...
                 ^
 -- accessing non-existing column in NULL datum errors out
-SELECT (NULL::compositetable).nonexistant;
-ERROR:  column "nonexistant" not found in data type compositetable
-LINE 1: SELECT (NULL::compositetable).nonexistant;
+SELECT (NULL::compositetable).nonexistent;
+ERROR:  column "nonexistent" not found in data type compositetable
+LINE 1: SELECT (NULL::compositetable).nonexistent;
                 ^
 -- existing column in a NULL composite yield NULL
 SELECT (NULL::compositetable).a;
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 6dfca7a6069..046d0b17217 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -35,8 +35,8 @@ CREATE STATISTICS tst FROM sometab;
 ERROR:  syntax error at or near "FROM"
 LINE 1: CREATE STATISTICS tst FROM sometab;
                               ^
-CREATE STATISTICS tst ON a, b FROM nonexistant;
-ERROR:  relation "nonexistant" does not exist
+CREATE STATISTICS tst ON a, b FROM nonexistent;
+ERROR:  relation "nonexistent" does not exist
 CREATE STATISTICS tst ON a, b FROM pg_class;
 ERROR:  column "a" does not exist
 CREATE STATISTICS tst ON relname, relname, relnatts FROM pg_class;
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 8a1173d8957..e8e094ab777 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -973,7 +973,7 @@ delete from atacc1;
 -- try dropping a non-existent column, should fail
 alter table atacc1 drop bar;
 
--- try removing an oid column, should succeed (as it's nonexistant)
+-- try removing an oid column, should succeed (as it's nonexistent)
 alter table atacc1 SET WITHOUT OIDS;
 
 -- try adding an oid column, should fail (not supported)
@@ -2152,7 +2152,7 @@ ALTER TABLE list_parted ATTACH PARTITION fail_part FOR VALUES FROM (1) TO (10);
 DROP TABLE fail_part;
 
 -- check that the table being attached exists
-ALTER TABLE list_parted ATTACH PARTITION nonexistant FOR VALUES IN (1);
+ALTER TABLE list_parted ATTACH PARTITION nonexistent FOR VALUES IN (1);
 
 -- check ownership of the source table
 CREATE ROLE regress_test_me;
diff --git a/src/test/regress/sql/create_am.sql b/src/test/regress/sql/create_am.sql
index dc6c8ba2e96..a7f6de7e9be 100644
--- a/src/test/regress/sql/create_am.sql
+++ b/src/test/regress/sql/create_am.sql
@@ -80,7 +80,7 @@ DROP ACCESS METHOD gist2 CASCADE;
 -- prevent empty values
 SET default_table_access_method = '';
 
--- prevent nonexistant values
+-- prevent nonexistent values
 SET default_table_access_method = 'I do not exist AM';
 
 -- prevent setting it to an index AM
@@ -198,7 +198,7 @@ ORDER BY 3, 1, 2;
 -- don't want to keep those tables, nor the default
 ROLLBACK;
 
--- Third, check that we can neither create a table using a nonexistant
+-- Third, check that we can neither create a table using a nonexistent
 -- AM, nor using an index AM
 CREATE TABLE i_am_a_failure() USING "";
 CREATE TABLE i_am_a_failure() USING i_do_not_exist_am;
diff --git a/src/test/regress/sql/rowtypes.sql b/src/test/regress/sql/rowtypes.sql
index 45f60e8625a..7e080c034cd 100644
--- a/src/test/regress/sql/rowtypes.sql
+++ b/src/test/regress/sql/rowtypes.sql
@@ -486,7 +486,7 @@ SELECT (d).a, (d).b FROM (SELECT compositetable AS d FROM compositetable) s;
 SELECT (d).ctid FROM (SELECT compositetable AS d FROM compositetable) s;
 
 -- accessing non-existing column in NULL datum errors out
-SELECT (NULL::compositetable).nonexistant;
+SELECT (NULL::compositetable).nonexistent;
 -- existing column in a NULL composite yield NULL
 SELECT (NULL::compositetable).a;
 -- oids can't be accessed in composite types (error)
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index c6a5776120e..d3337308724 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -29,7 +29,7 @@ $$;
 CREATE STATISTICS tst;
 CREATE STATISTICS tst ON a, b;
 CREATE STATISTICS tst FROM sometab;
-CREATE STATISTICS tst ON a, b FROM nonexistant;
+CREATE STATISTICS tst ON a, b FROM nonexistent;
 CREATE STATISTICS tst ON a, b FROM pg_class;
 CREATE STATISTICS tst ON relname, relname, relnatts FROM pg_class;
 CREATE STATISTICS tst ON relnatts + relpages FROM pg_class;