diff --git a/pkg/cmd/roachtest/testdata/pg_regress/horology.diffs b/pkg/cmd/roachtest/testdata/pg_regress/horology.diffs
index 7dc57fca04f0..a7f451229427 100644
--- a/pkg/cmd/roachtest/testdata/pg_regress/horology.diffs
+++ b/pkg/cmd/roachtest/testdata/pg_regress/horology.diffs
@@ -1212,23 +1212,6 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/horology.out --la
  SELECT time with time zone '01:30-08' - interval '02:01' AS "23:29:00-08";
   23:29:00-08 
  -------------
-@@ -1034,14 +661,14 @@
-             + interval '02:01' AS time with time zone) AS time) AS "07:31:00";
-  07:31:00 
- ----------
-- 07:31:00
-+ 08:31:00
- (1 row)
- 
- SELECT CAST(cast(date 'today' + time with time zone '03:30'
-   + interval '1 month 04:01' as timestamp without time zone) AS time) AS "07:31:00";
-  07:31:00 
- ----------
-- 07:31:00
-+ 08:31:00
- (1 row)
- 
- SELECT t.d1 AS t, i.f1 AS i, t.d1 + i.f1 AS "add", t.d1 - i.f1 AS "subtract"
 @@ -1049,347 +676,67 @@
    WHERE t.d1 BETWEEN '1990-01-01' AND '2001-01-01'
      AND i.f1 BETWEEN '00:00' AND '23:00'
@@ -2954,13 +2937,13 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/horology.out --la
 - 1997-02-10 17:32:00
 - 1997-02-10 17:32:01
 - 1997-02-10 17:32:01
+- 1997-02-10 17:32:01
 - 1997-02-10 17:32:01
   1997-02-10 17:32:01
   1997-02-10 17:32:01
   1997-02-10 17:32:01
   1997-02-10 17:32:01
 - 1997-02-10 17:32:01
-- 1997-02-10 17:32:01
 - 1997-06-10 18:32:01
 - 1997-02-10 17:32:01
 - 1997-02-11 17:32:01
diff --git a/pkg/cmd/roachtest/testdata/pg_regress/identity.diffs b/pkg/cmd/roachtest/testdata/pg_regress/identity.diffs
index d5c48f0d362f..799b05725860 100644
--- a/pkg/cmd/roachtest/testdata/pg_regress/identity.diffs
+++ b/pkg/cmd/roachtest/testdata/pg_regress/identity.diffs
@@ -493,7 +493,7 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/identity.out --la
  ALTER TABLE itest3
    ADD COLUMN c int GENERATED BY DEFAULT AS IDENTITY,
    ALTER COLUMN c SET GENERATED ALWAYS;
-+ERROR:  unimplemented: cannot evaluate scalar expressions containing sequence operations in this context
++ERROR:  failed to construct index entries during backfill: unimplemented: cannot evaluate scalar expressions containing sequence operations in this context
 +HINT:  You have attempted to use a feature that is not yet implemented.
 +See: https://go.crdb.dev/issue-v/42508/_version_
  \d itest3
@@ -626,7 +626,7 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/identity.out --la
  
  RESET ROLE;
  DROP TABLE itest8;
-@@ -471,12 +550,20 @@
+@@ -471,6 +550,13 @@
    ADD COLUMN f3 int NOT NULL,
    ALTER COLUMN f3 ADD GENERATED ALWAYS AS IDENTITY,
    ALTER COLUMN f3 SET GENERATED BY DEFAULT SET INCREMENT 10;
@@ -640,14 +640,7 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/identity.out --la
  ALTER TABLE itest8
    ADD COLUMN f4 int;
  ALTER TABLE itest8
-   ALTER COLUMN f4 SET NOT NULL,
-   ALTER COLUMN f4 ADD GENERATED ALWAYS AS IDENTITY,
-   ALTER COLUMN f4 SET DATA TYPE bigint;
-+ERROR:  column "f4" of relation "itest8" must be declared NOT NULL before identity can be added
- ALTER TABLE itest8
-   ADD COLUMN f5 int GENERATED ALWAYS AS IDENTITY;
- ALTER TABLE itest8
-@@ -489,59 +576,94 @@
+@@ -489,59 +575,94 @@
  ALTER TABLE itest8
    ADD COLUMN f22 int NOT NULL,
    ALTER COLUMN f22 ADD GENERATED ALWAYS AS IDENTITY;
@@ -660,8 +653,8 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/identity.out --la
 -  1 |  2 | 11 |  2 |   
 + f1 | f2 | f4 | f5 
 +----+----+----+----
-+  0 |  1 |    |   
-+  1 |  2 |    |   
++  0 |  1 |  1 |   
++  1 |  2 |  2 |   
  (2 rows)
  
  \d+ itest8
@@ -776,7 +769,7 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/identity.out --la
  -- test that sequence of half-dropped serial column is properly ignored
  CREATE TABLE itest14 (id serial);
  ALTER TABLE itest14 ALTER id DROP DEFAULT;
-@@ -549,13 +671,15 @@
+@@ -549,13 +670,15 @@
  INSERT INTO itest14 (id) VALUES (DEFAULT);
  -- Identity columns must be NOT NULL (cf bug #16913)
  CREATE TABLE itest15 (id integer GENERATED ALWAYS AS IDENTITY NULL); -- fail
@@ -798,7 +791,7 @@ diff -U3 --label=/mnt/data1/postgres/src/test/regress/expected/identity.out --la
  CREATE TABLE itest15 (id integer GENERATED ALWAYS AS IDENTITY NOT NULL);
  DROP TABLE itest15;
  CREATE TABLE itest15 (id integer NOT NULL GENERATED ALWAYS AS IDENTITY);
-@@ -568,49 +692,65 @@
+@@ -568,49 +691,65 @@
  ON t.a = s.s_a
  WHEN NOT MATCHED THEN
  	INSERT (a, b) VALUES (s.s_a, s.s_b);