diff --git a/sql/upgrades/161.sql b/sql/upgrades/161.sql
--- a/sql/upgrades/161.sql
+++ b/sql/upgrades/161.sql
@@ -12,6 +12,10 @@
     set extra_headers = ARRAY[]::bytea[][]
     where extra_headers is null;
 
+alter table revision
+    add constraint revision_extra_headers_not_null
+    check (extra_headers is not null)
+    not valid;
 
 alter table revision
-    alter column extra_headers set not null;
+    validate constraint revision_extra_headers_not_null;
diff --git a/swh/storage/sql/30-swh-schema.sql b/swh/storage/sql/30-swh-schema.sql
--- a/swh/storage/sql/30-swh-schema.sql
+++ b/swh/storage/sql/30-swh-schema.sql
@@ -238,9 +238,9 @@
   synthetic             boolean not null default false,  -- true iff revision has been created by Software Heritage
   metadata              jsonb,  -- extra metadata (tarball checksums, extra commit information, etc...)
   object_id             bigserial,
-  date_neg_utc_offset   boolean,
-  committer_date_neg_utc_offset boolean,
-  extra_headers         bytea[][] not null  -- extra headers (used in hash computation)
+  date_neg_utc_offset   boolean,  -- not null, check 60-swh-indexes.sql
+  committer_date_neg_utc_offset boolean,  -- not null, check 60-swh-indexes.sql
+  extra_headers         bytea[][]  -- not null, check 60-swh-indexes.sql (this is used in hash computation)
 );
 
 comment on table revision is 'A revision represents the state of a source code tree at a specific point in time';
diff --git a/swh/storage/sql/60-swh-indexes.sql b/swh/storage/sql/60-swh-indexes.sql
--- a/swh/storage/sql/60-swh-indexes.sql
+++ b/swh/storage/sql/60-swh-indexes.sql
@@ -89,11 +89,17 @@
     add constraint revision_committer_date_neg_utc_offset_not_null
     check (committer_date is null or committer_date_neg_utc_offset is not null)
     not valid;
+alter table revision
+    add constraint revision_extra_headers_not_null
+    check (extra_headers is not null)
+    not valid;
 
 alter table revision
     validate constraint revision_date_neg_utc_offset_not_null;
 alter table revision
     validate constraint revision_committer_date_neg_utc_offset_not_null;
+alter table revision
+    validate constraint revision_extra_headers_not_null;
 
 create index concurrently on revision(directory);
 create unique index concurrently on revision(object_id);