diff --git a/sql/upgrades/137.sql b/sql/upgrades/137.sql
new file mode 100644
--- /dev/null
+++ b/sql/upgrades/137.sql
@@ -0,0 +1,44 @@
+-- SWH DB schema upgrade
+-- from_version: 136
+-- to_version: 137
+-- description: Add comment columns to all tables
+
+insert into dbversion(version, release, description)
+      values(137, now(), 'Work In Progress');
+
+-- comment for columns of dbversion table
+comment on column dbversion.version is 'Current version for sql schema';
+comment on column dbversion.release is 'Release date and time for current version';
+comment on column dbversion.description is 'Description for current release';
+
+-- comment for columns of content table
+comment on column content.sha1 is 'Sha1 checksum of file content';
+comment on column content.sha1_git is 'Git id of sha1 checksum';
+comment on column content.sha256 is 'Sha256 checksum of file content';
+comment on column content.blake2s256 is 'Blake2s checksum of file content';
+comment on column content.length is 'Length of file content';
+comment on column content.ctime is 'Time of file creation';
+comment on column content.status is 'Status of content (absent, visible, hidden)';
+comment on column content.object_id is 'File content identifier';
+
+-- comment for columns of skipped_content
+comment on column skipped_content.sha1 is 'Sha1 checksum of skipped content';
+comment on column skipped_content.sha1_git is 'Git id of sha1 checksum';
+comment on column skipped_content.sha256 is 'Sha256 checksum of skipped content';
+comment on column skipped_content.blake2s256 is 'Blake2s checksum of skipped content';
+comment on column skipped_content.length is 'Length of skipped content';
+comment on column skipped_content.ctime is 'Time of file creation';
+comment on column skipped_content.status is 'Status of skipped content (absent, visible, hidden)';
+comment on column skipped_content.reason is 'Reason for skipping content';
+comment on column skipped_content.origin is 'Foreign key for origin table';
+comment on column skipped_content.object_id is 'Skipped content identifier';
+
+-- comment for columns of fetch_history
+comment on column fetch_history.id IS 'Identifier for fetch history';
+comment on column fetch_history.origin IS 'Foreign key for origin table';
+comment on column fetch_history."date" IS 'Date of entry';
+comment on column fetch_history.status IS 'True indicates successful fetch';
+comment on column fetch_history."result" IS 'Detailed return values, times etc';
+comment on column fetch_history.stdout IS 'Console output of fetch';
+comment on column fetch_history.stderr IS 'Error message for fetch';
+comment on column fetch_history.duration IS 'Time taken to complete fetch, NULL if ongoing';
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
@@ -10,9 +10,13 @@
   description text
 );
 
+comment on column dbversion.version is 'Current version for sql schema';
+comment on column dbversion.release is 'Release date and time for current version';
+comment on column dbversion.description is 'Description for current release';
+
 -- latest schema version
 insert into dbversion(version, release, description)
-      values(133, now(), 'Work In Progress');
+      values(137, now(), 'Work In Progress');
 
 -- a SHA1 checksum
 create domain sha1 as bytea check (length(value) = 20);
@@ -50,6 +54,15 @@
   object_id  bigserial
 );
 
+comment on column content.sha1 is 'Sha1 checksum of file content';
+comment on column content.sha1_git is 'Git id of sha1 checksum';
+comment on column content.sha256 is 'Sha256 checksum of file content';
+comment on column content.blake2s256 is 'Blake2s checksum of file content';
+comment on column content.length is 'Length of file content';
+comment on column content.ctime is 'Time of file creation';
+comment on column content.status is 'Status of content (absent, visible, hidden)';
+comment on column content.object_id is 'File content identifier';
+
 
 -- An origin is a place, identified by an URL, where software source code
 -- artifacts can be found. We support different kinds of origins, e.g., git and
@@ -65,6 +78,10 @@
   url      text not null
 );
 
+comment on column origin.id is 'Artifact origin id';
+comment on column origin.type is 'Type of origin';
+comment on column origin.url is 'Url of origin';
+
 
 -- Content blobs observed somewhere, but not ingested into the archive for
 -- whatever reason. This table is separate from the content table as we might
@@ -87,6 +104,17 @@
   object_id  bigserial
 );
 
+comment on column skipped_content.sha1 is 'Sha1 checksum of skipped content';
+comment on column skipped_content.sha1_git is 'Git id of sha1 checksum';
+comment on column skipped_content.sha256 is 'Sha256 checksum of skipped content';
+comment on column skipped_content.blake2s256 is 'Blake2s checksum of skipped content';
+comment on column skipped_content.length is 'Length of skipped content';
+comment on column skipped_content.ctime is 'Time of file creation';
+comment on column skipped_content.status is 'Status of skipped content (absent, visible, hidden)';
+comment on column skipped_content.reason is 'Reason for skipping content';
+comment on column skipped_content.origin is 'Foreign key for origin table';
+comment on column skipped_content.object_id is 'Skipped content identifier';
+
 
 -- Log of all origin fetches (i.e., origin crawling) that have been done in the
 -- past, or are still ongoing. Similar to list_history, but for origins.
@@ -102,6 +130,15 @@
   duration  interval  -- fetch duration of NULL if still ongoing
 );
 
+comment on column fetch_history.id IS 'Identifier for fetch history';
+comment on column fetch_history.origin IS 'Foreign key for origin table';
+comment on column fetch_history."date" IS 'Date of entry';
+comment on column fetch_history.status IS 'True indicates successful fetch';
+comment on column fetch_history."result" IS 'Detailed return values, times etc';
+comment on column fetch_history.stdout IS 'Console output of fetch';
+comment on column fetch_history.stderr IS 'Error message for fetch';
+comment on column fetch_history.duration IS 'Time taken to complete fetch, NULL if ongoing';
+
 
 -- A file-system directory.  A directory is a list of directory entries (see
 -- tables: directory_entry_{dir,file}).