diff --git a/sql/swh-schema.sql b/sql/swh-schema.sql
index ea9261e6..1f71906e 100644
--- a/sql/swh-schema.sql
+++ b/sql/swh-schema.sql
@@ -1,434 +1,557 @@
 ---
 --- Software Heritage Data Model
 ---
 
 -- drop schema if exists swh cascade;
 -- create schema swh;
 -- set search_path to swh;
 
 create table dbversion
 (
   version     int primary key,
   release     timestamptz,
   description text
 );
 
 insert into dbversion(version, release, description)
-      values(73, now(), 'Work In Progress');
+      values(74, now(), 'Work In Progress');
 
 -- a SHA1 checksum (not necessarily originating from Git)
 create domain sha1 as bytea check (length(value) = 20);
 
 -- a Git object ID, i.e., a SHA1 checksum
 create domain sha1_git as bytea check (length(value) = 20);
 
 -- a SHA256 checksum
 create domain sha256 as bytea check (length(value) = 32);
 
 -- UNIX path (absolute, relative, individual path component, etc.)
 create domain unix_path as bytea;
 
 -- a set of UNIX-like access permissions, as manipulated by, e.g., chmod
 create domain file_perms as int;
 
 create type content_status as enum ('absent', 'visible', 'hidden');
 
 -- Checksums about actual file content. Note that the content itself is not
 -- stored in the DB, but on external (key-value) storage. A single checksum is
 -- used as key there, but the other can be used to verify that we do not inject
 -- content collisions not knowingly.
 create table content
 (
   sha1      sha1 primary key,
   sha1_git  sha1_git not null,
   sha256    sha256 not null,
   length    bigint not null,
   ctime     timestamptz not null default now(),
             -- creation time, i.e. time of (first) injection into the storage
   status    content_status not null default 'visible',
   object_id bigserial
 );
 
 create unique index on content(sha1_git);
 create unique index on content(sha256);
 create index on content(ctime);  -- TODO use a BRIN index here (postgres >= 9.5)
 create index on content(object_id);
 
+-- Asynchronous notification of new content insertions
+create function notify_new_content()
+  returns trigger
+  language plpgsql
+as $$
+  begin
+    perform pg_notify('new_content', encode(new.sha1, 'hex'));
+    return null;
+  end;
+$$;
+
+create trigger notify_new_content
+  after insert on content
+  for each row
+  execute procedure notify_new_content();
+
+
 -- Entities constitute a typed hierarchy of organization, hosting
 -- facilities, groups, people and software projects.
 --
 -- Examples of entities: Software Heritage, Debian, GNU, GitHub,
 -- Apache, The Linux Foundation, the Debian Python Modules Team, the
 -- torvalds GitHub user, the torvalds/linux GitHub project.
 --
 -- The data model is hierarchical (via the parent attribute) and might
 -- store sub-branches of existing entities. The key feature of an
 -- entity is might be *listed* (if it is available in listable_entity)
 -- to retrieve information about its content, i.e: sub-entities,
 -- projects, origins.
 
 -- Types of entities.
 --
 -- - organization: a root entity, usually backed by a non-profit, a
 -- company, or another kind of "association". (examples: Software
 -- Heritage, Debian, GNU, GitHub)
 --
 -- - group_of_entities: used for hierarchies, doesn't need to have a
 -- concrete existence. (examples: GNU hosting facilities, Debian
 -- hosting facilities, GitHub users, ...)
 --
 -- - hosting: a hosting facility, can usually be listed to generate
 -- other data. (examples: GitHub git hosting, alioth.debian.org,
 -- snapshot.debian.org)
 --
 -- - group_of_persons: an entity representing a group of
 -- persons. (examples: a GitHub organization, a Debian team)
 --
 -- - person: an entity representing a person. (examples:
 -- a GitHub user, a Debian developer)
 --
 -- - project: an entity representing a software project. (examples: a
 -- GitHub project, Apache httpd, a Debian source package, ...)
 create type entity_type as enum (
   'organization',
   'group_of_entities',
   'hosting',
   'group_of_persons',
   'person',
   'project'
 );
 
 -- The history of entities. Allows us to keep historical metadata
 -- about entities.  The temporal invariant is the uuid. Root
 -- organization uuids are manually generated (and available in
 -- swh-data.sql).
 --
 -- For generated entities (generated = true), we can provide
 -- generation_metadata to allow listers to retrieve the uuids of previous
 -- iterations of the entity.
 --
 -- Inactive entities that have been active in the past (active =
 -- false) should register the timestamp at which we saw them
 -- deactivate, in a new entry of entity_history.
 create table entity_history
 (
   id               bigserial primary key,
   uuid             uuid,
   parent           uuid,             -- should reference entity_history(uuid)
   name             text not null,
   type             entity_type not null,
   description      text,
   homepage         text,
   active           boolean not null, -- whether the entity was seen on the last listing
   generated        boolean not null, -- whether this entity has been generated by a lister
   lister_metadata  jsonb,            -- lister-specific metadata, used for queries
   metadata         jsonb,
   validity         timestamptz[]     -- timestamps at which we have seen this entity
 );
 
 create index on entity_history(uuid);
 create index on entity_history(name);
 
 -- The entity table provides a view of the latest information on a
 -- given entity. It is updated via a trigger on entity_history.
 create table entity
 (
   uuid             uuid primary key,
   parent           uuid references entity(uuid) deferrable initially deferred,
   name             text not null,
   type             entity_type not null,
   description      text,
   homepage         text,
   active           boolean not null, -- whether the entity was seen on the last listing
   generated        boolean not null, -- whether this entity has been generated by a lister
   lister_metadata  jsonb,            -- lister-specific metadata, used for queries
   metadata         jsonb,
   last_seen        timestamptz,      -- last listing time or disappearance time for active=false
   last_id          bigint references entity_history(id) -- last listing id
 );
 
 create index on entity(name);
 create index on entity using gin(lister_metadata jsonb_path_ops);
 
 -- Register the equivalence between two entities. Allows sideways
 -- navigation in the entity table
 create table entity_equivalence
 (
   entity1 uuid references entity(uuid),
   entity2 uuid references entity(uuid),
   primary key (entity1, entity2),
   constraint order_entities check (entity1 < entity2)
 );
 
 -- Register a lister for a specific entity.
 create table listable_entity
 (
   uuid         uuid references entity(uuid) primary key,
   enabled      boolean not null default true, -- do we list this entity automatically?
   list_engine  text,  -- crawler to be used to list entity's content
   list_url     text,  -- root URL to start the listing
   list_params  jsonb,  -- org-specific listing parameter
   latest_list  timestamptz  -- last time the entity's content has been listed
 );
 
 -- Log of all entity listings (i.e., entity crawling) that have been
 -- done in the past, or are still ongoing.
 create table list_history
 (
   id        bigserial primary key,
   entity    uuid references listable_entity(uuid),
   date      timestamptz not null,
   status    boolean,  -- true if and only if the listing has been successful
   result    jsonb,     -- more detailed return value, depending on status
   stdout    text,
   stderr    text,
   duration  interval  -- fetch duration of NULL if still ongoing
 );
 
 
 -- An origin is a place, identified by an URL, where software can be found. We
 -- support different kinds of origins, e.g., git and other VCS repositories,
 -- web pages that list tarballs URLs (e.g., http://www.kernel.org), indirect
 -- tarball URLs (e.g., http://www.example.org/latest.tar.gz), etc. The key
 -- feature of an origin is that it can be *fetched* (wget, git clone, svn
 -- checkout, etc.) to retrieve all the contained software.
 create table origin
 (
   id       bigserial primary key,
   type     text, -- TODO use an enum here (?)
   url      text not null,
   lister   uuid references listable_entity(uuid),
   project  uuid references entity(uuid)
 );
 
 create index on origin(type, url);
 
+-- Asynchronous notification of new origin insertions
+create function notify_new_origin()
+  returns trigger
+  language plpgsql
+as $$
+  begin
+    perform pg_notify('new_origin', new.id::text);
+    return null;
+  end;
+$$;
+
+create trigger notify_new_origin
+  after insert on origin
+  for each row
+  execute procedure notify_new_origin();
+
 -- Content we have seen but skipped for some reason. This table is
 -- separate from the content table as we might not have the sha1
 -- checksum of that data (for instance when we inject git
 -- repositories, objects that are too big will be skipped here, and we
 -- will only know their sha1_git). 'reason' contains the reason the
 -- content was skipped. origin is a nullable column allowing to find
 -- out which origin contains that skipped content.
 create table skipped_content
 (
   sha1      sha1,
   sha1_git  sha1_git,
   sha256    sha256,
   length    bigint not null,
   ctime     timestamptz not null default now(),
   status    content_status not null default 'absent',
   reason    text not null,
   origin    bigint references origin(id),
   object_id bigserial,
   unique (sha1, sha1_git, sha256)
 );
 
--- those indexes support multiple NULL values.
+-- Those indexes support multiple NULL values.
 create unique index on skipped_content(sha1);
 create unique index on skipped_content(sha1_git);
 create unique index on skipped_content(sha256);
 create index on skipped_content(object_id);
 
+-- Asynchronous notification of new skipped content insertions
+create function notify_new_skipped_content()
+  returns trigger
+  language plpgsql
+as $$
+  begin
+  perform pg_notify('new_skipped_content', json_build_object(
+      'sha1', encode(new.sha1, 'hex'),
+      'sha1_git', encode(new.sha1_git, 'hex'),
+      'sha256', encode(new.sha256, 'hex')
+    )::text);
+    return null;
+  end;
+$$;
+
+create trigger notify_new_skipped_content
+  after insert on skipped_content
+  for each row
+  execute procedure notify_new_skipped_content();
+
 
 -- 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.
 create table fetch_history
 (
   id        bigserial primary key,
   origin    bigint references origin(id),
   date      timestamptz not null,
   status    boolean,  -- true if and only if the fetch has been successful
   result    jsonb,     -- more detailed returned values, times, etc...
   stdout    text,
   stderr    text,     -- null when status is true, filled otherwise
   duration  interval  -- fetch duration of NULL if still ongoing
 );
 
 
 -- A file-system directory.  A directory is a list of directory entries (see
 -- tables: directory_entry_{dir,file}).
 --
 -- To list the contents of a directory:
 -- 1. list the contained directory_entry_dir using array dir_entries
 -- 2. list the contained directory_entry_file using array file_entries
 -- 3. list the contained directory_entry_rev using array rev_entries
 -- 4. UNION
 --
 -- Synonyms/mappings:
 -- * git: tree
 create table directory
 (
   id            sha1_git primary key,
   dir_entries   bigint[],  -- sub-directories, reference directory_entry_dir
   file_entries  bigint[],  -- contained files, reference directory_entry_file
   rev_entries   bigint[],  -- mounted revisions, reference directory_entry_rev
   object_id     bigserial  -- short object identifier
 );
 
 create index on directory using gin (dir_entries);
 create index on directory using gin (file_entries);
 create index on directory using gin (rev_entries);
 create index on directory(object_id);
 
+-- Asynchronous notification of new directory insertions
+create function notify_new_directory()
+  returns trigger
+  language plpgsql
+as $$
+  begin
+    perform pg_notify('new_directory', encode(new.id, 'hex'));
+    return null;
+  end;
+$$;
+
+create trigger notify_new_directory
+  after insert on directory
+  for each row
+  execute procedure notify_new_directory();
+
+
 -- A directory entry pointing to a sub-directory.
 create table directory_entry_dir
 (
   id      bigserial primary key,
   target  sha1_git,   -- id of target directory
   name    unix_path,  -- path name, relative to containing dir
   perms   file_perms  -- unix-like permissions
 );
 
 create unique index on directory_entry_dir(target, name, perms);
 
 -- A directory entry pointing to a file.
 create table directory_entry_file
 (
   id      bigserial primary key,
   target  sha1_git,   -- id of target file
   name    unix_path,  -- path name, relative to containing dir
   perms   file_perms  -- unix-like permissions
 );
 
 create unique index on directory_entry_file(target, name, perms);
 
 -- A directory entry pointing to a revision.
 create table directory_entry_rev
 (
   id      bigserial primary key,
   target  sha1_git,   -- id of target revision
   name    unix_path,  -- path name, relative to containing dir
   perms   file_perms  -- unix-like permissions
 );
 
 create unique index on directory_entry_rev(target, name, perms);
 
 create table person
 (
   id        bigserial primary key,
   fullname  bytea not null, -- freeform specification; what is actually used in the checksums
                             --     will usually be of the form 'name <email>'
   name      bytea,          -- advisory: not null if we managed to parse a name
   email     bytea           -- advisory: not null if we managed to parse an email
 );
 
 create unique index on person(fullname);
 create index on person(name);
 create index on person(email);
 
 create type revision_type as enum ('git', 'tar', 'dsc', 'svn');
 
 -- the data object types stored in our data model
 create type object_type as enum ('content', 'directory', 'revision', 'release');
 
 -- A snapshot of a software project at a specific point in time.
 --
 -- Synonyms/mappings:
 -- * git / subversion / etc: commit
 -- * tarball: a specific tarball
 --
 -- Revisions are organized as DAGs. Each revision points to 0, 1, or more (in
 -- case of merges) parent revisions. Each revision points to a directory, i.e.,
 -- a file-system tree containing files and directories.
 create table revision
 (
   id                    sha1_git primary key,
   date                  timestamptz,
   date_offset           smallint,
   date_neg_utc_offset   boolean,
   committer_date        timestamptz,
   committer_date_offset smallint,
   committer_date_neg_utc_offset boolean,
   type                  revision_type not null,
   directory             sha1_git,  -- file-system tree
   message               bytea,
   author                bigint references person(id),
   committer             bigint references person(id),
   metadata              jsonb, -- extra metadata (tarball checksums, extra commit information, etc...)
   synthetic             boolean not null default false,  -- true if synthetic (cf. swh-loader-tar)
   object_id             bigserial
 );
 
 create index on revision(directory);
 create index on revision(object_id);
 
+-- Asynchronous notification of new revision insertions
+create function notify_new_revision()
+  returns trigger
+  language plpgsql
+as $$
+  begin
+    perform pg_notify('new_revision', encode(new.id, 'hex'));
+    return null;
+  end;
+$$;
+
+create trigger notify_new_revision
+  after insert on revision
+  for each row
+  execute procedure notify_new_revision();
+
+
 -- either this table or the sha1_git[] column on the revision table
 create table revision_history
 (
   id           sha1_git references revision(id),
   parent_id    sha1_git,
   parent_rank  int not null default 0,
     -- parent position in merge commits, 0-based
   primary key (id, parent_rank)
 );
 
 create index on revision_history(parent_id);
 
 -- The timestamps at which Software Heritage has made a visit of the given origin.
 create table origin_visit
 (
   origin  bigint not null references origin(id),
   visit   bigint not null,
   date    timestamptz not null,
   primary key (origin, visit)
 );
 
 create index on origin_visit(date);
 
+-- Asynchronous notification of new origin visits
+create function notify_new_origin_visit()
+  returns trigger
+  language plpgsql
+as $$
+  begin
+    perform pg_notify('new_origin_visit', json_build_object(
+      'origin', new.origin,
+      'visit', new.visit
+    )::text);
+    return null;
+  end;
+$$;
+
+create trigger notify_new_origin_visit
+  after insert on origin_visit
+  for each row
+  execute procedure notify_new_origin_visit();
+
+
 -- The content of software origins is indexed starting from top-level pointers
 -- called "branches". Every time we fetch some origin we store in this table
 -- where the branches pointed to at fetch time.
 --
 -- Synonyms/mappings:
 -- * git: ref (in the "git update-ref" sense)
 create table occurrence_history
 (
   origin       bigint references origin(id) not null,
   branch       bytea not null,        -- e.g., b"master" (for VCS), or b"sid" (for Debian)
   target       sha1_git not null,     -- ref target, e.g., commit id
   target_type  object_type not null,  -- ref target type
   object_id    bigserial not null,    -- short object identifier
   visits       bigint[] not null,     -- the visits where that occurrence was valid. References
                                       -- origin_visit(visit), where o_h.origin = origin_visit.origin.
   primary key (object_id)
 );
 
 create index on occurrence_history(target, target_type);
 create index on occurrence_history(origin, branch);
 create unique index on occurrence_history(origin, branch, target, target_type);
 create index on occurrence_history(object_id);
 
 -- Materialized view of occurrence_history, storing the *current* value of each
 -- branch, as last seen by SWH.
 create table occurrence
 (
   origin    bigint references origin(id) not null,
   branch    bytea not null,
   target    sha1_git not null,
   target_type object_type not null,
   primary key(origin, branch)
 );
 
 -- A "memorable" point in the development history of a project.
 --
 -- Synonyms/mappings:
 -- * git: tag (of the annotated kind, otherwise they are just references)
 -- * tarball: the release version number
 create table release
 (
   id          sha1_git primary key,
   target      sha1_git,
   target_type object_type,
   date        timestamptz,
   date_offset smallint,
   date_neg_utc_offset  boolean,
   name        bytea,
   comment     bytea,
   author      bigint references person(id),
   synthetic   boolean not null default false,  -- true if synthetic (cf. swh-loader-tar)
   object_id   bigserial
 );
 
 create index on release(target, target_type);
 create index on release(object_id);
+
+-- Asynchronous notification of new release insertions
+create function notify_new_release()
+  returns trigger
+  language plpgsql
+as $$
+  begin
+    perform pg_notify('new_release', encode(new.id, 'hex'));
+    return null;
+  end;
+$$;
+
+create trigger notify_new_release
+  after insert on release
+  for each row
+  execute procedure notify_new_release();
diff --git a/sql/upgrades/074.sql b/sql/upgrades/074.sql
new file mode 100644
index 00000000..07cc5bcd
--- /dev/null
+++ b/sql/upgrades/074.sql
@@ -0,0 +1,112 @@
+-- SWH DB schema upgrade
+-- from_version: 73
+-- to_version: 74
+-- description: Add notifications for object creations in the whole database
+
+insert into dbversion(version, release, description)
+      values(74, now(), 'Work In Progress');
+
+CREATE OR REPLACE FUNCTION notify_new_content() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+  begin
+    perform pg_notify('new_content', encode(new.sha1, 'hex'));
+    return null;
+  end;
+$$;
+
+CREATE OR REPLACE FUNCTION notify_new_directory() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+  begin
+    perform pg_notify('new_directory', encode(new.id, 'hex'));
+    return null;
+  end;
+$$;
+
+CREATE OR REPLACE FUNCTION notify_new_origin() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+  begin
+    perform pg_notify('new_origin', new.id::text);
+    return null;
+  end;
+$$;
+
+CREATE OR REPLACE FUNCTION notify_new_origin_visit() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+  begin
+    perform pg_notify('new_origin_visit', json_build_object(
+      'origin', new.origin,
+      'visit', new.visit
+    )::text);
+    return null;
+  end;
+$$;
+
+CREATE OR REPLACE FUNCTION notify_new_release() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+  begin
+    perform pg_notify('new_release', encode(new.id, 'hex'));
+    return null;
+  end;
+$$;
+
+CREATE OR REPLACE FUNCTION notify_new_revision() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+  begin
+    perform pg_notify('new_revision', encode(new.id, 'hex'));
+    return null;
+  end;
+$$;
+
+CREATE OR REPLACE FUNCTION notify_new_skipped_content() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+  begin
+  perform pg_notify('new_skipped_content', json_build_object(
+      'sha1', encode(new.sha1, 'hex'),
+      'sha1_git', encode(new.sha1_git, 'hex'),
+      'sha256', encode(new.sha256, 'hex')
+    )::text);
+    return null;
+  end;
+$$;
+
+CREATE TRIGGER notify_new_content
+	AFTER INSERT ON content
+	FOR EACH ROW
+	EXECUTE PROCEDURE notify_new_content();
+
+CREATE TRIGGER notify_new_directory
+	AFTER INSERT ON directory
+	FOR EACH ROW
+	EXECUTE PROCEDURE notify_new_directory();
+
+CREATE TRIGGER notify_new_origin_visit
+	AFTER INSERT ON origin_visit
+	FOR EACH ROW
+	EXECUTE PROCEDURE notify_new_origin_visit();
+
+CREATE TRIGGER notify_new_origin
+	AFTER INSERT ON origin
+	FOR EACH ROW
+	EXECUTE PROCEDURE notify_new_origin();
+
+CREATE TRIGGER notify_new_release
+	AFTER INSERT ON "release"
+	FOR EACH ROW
+	EXECUTE PROCEDURE notify_new_release();
+
+CREATE TRIGGER notify_new_revision
+	AFTER INSERT ON revision
+	FOR EACH ROW
+	EXECUTE PROCEDURE notify_new_revision();
+
+CREATE TRIGGER notify_new_skipped_content
+	AFTER INSERT ON skipped_content
+	FOR EACH ROW
+	EXECUTE PROCEDURE notify_new_skipped_content();