From df32557770b6c447908da1c0bf21a78cd63abe02 Mon Sep 17 00:00:00 2001
From: dece <shgck@pistache.land>
Date: Fri, 13 Sep 2024 14:59:59 +0200
Subject: [PATCH] reassign-postgres-db.sh

---
 reassign-postgres-db.sh | 125 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100755 reassign-postgres-db.sh

diff --git a/reassign-postgres-db.sh b/reassign-postgres-db.sh
new file mode 100755
index 0000000..103da6f
--- /dev/null
+++ b/reassign-postgres-db.sh
@@ -0,0 +1,125 @@
+#!/bin/bash
+#
+# Reassign a database owner and all its objects.
+#
+# But dece, there is REASSIGN OWNED!! Yes and it does not work if the owner is
+# `postgres` because it reassign objects across all databases, wrecking havok on
+# your cluster.
+#
+# This script manually alters the database owner, then for all public
+# (non-system) schemas it reassigns the owner of:
+# - the schema itself
+# - tables
+# - sequences
+# - views
+# - foreign tables
+#
+# Finally it also reassigns the owner of foreign servers. If you don't want them
+# to be reassigned, comment the block at the end of the script.
+#
+# If I'm missing something please let me know. This script is a base work to
+# modify to your needs.
+
+usage() {
+    echo "Usage: $0 <database> <new_owner>"
+}
+
+[ $# -ne 2 ] && usage && exit  # assumes usage is a defined command.
+
+info() {
+    printf '\e[33m%s\e[0m\n' "> $1"
+}
+
+database="$1"
+new_owner="$2"
+echo "🤖 <(Reassigning all objects of database \"$database\" to \"$new_owner\".)"
+
+# psql command, here we run it as the Unix user postgres, adapt as needed.
+# For simplicity, always add the database parameter.
+psql="sudo -u postgres psql -d $database"
+
+# Change global database owner.
+$psql -c "ALTER DATABASE \"$database\" OWNER TO $new_owner"
+
+# Loop over all schemas. Most databases will only use 'public'.
+schemas="$($psql -qAt -c "
+    SELECT nspname
+    FROM pg_catalog.pg_namespace
+    WHERE nspname != 'information_schema' AND nspname NOT LIKE 'pg\\_%';
+")"
+for schema in $schemas; do
+    info "Schema $schema"
+
+    $psql -c "ALTER SCHEMA $schema OWNER TO $new_owner"
+
+    echo "Reassigning tables…"
+    tables="$($psql -qAt -c "
+        SELECT tablename
+        FROM pg_tables
+        WHERE schemaname = '$schema'
+    ")"
+    for table in $tables ; do
+        echo -n "    $table "
+        $psql -c "ALTER TABLE \"$schema\".\"$table\" OWNER TO $new_owner"
+    done
+
+    echo "Reassigning sequences…"
+    sequences="$($psql -qAt -c "
+        SELECT sequence_name
+        FROM information_schema.sequences
+        WHERE sequence_schema = '$schema'
+    ")"
+    for sequence in $sequences ; do
+        echo -n "    $sequence "
+        $psql -c "ALTER SEQUENCE \"$schema\".\"$sequence\" OWNER TO $new_owner"
+    done
+
+    echo "Reassigning views…"
+    views="$($psql -qAt -c "
+        SELECT table_name
+        FROM information_schema.views
+        WHERE table_schema = '$schema'
+    ")"
+    for view in $views ; do
+        echo -n "    $view "
+        $psql -c "ALTER VIEW \"$schema\".\"$view\" OWNER TO $new_owner"
+    done
+
+    echo "Reassigning materialized views…"
+    mviews="$($psql -qAt -c "
+        SELECT matviewname
+        FROM pg_matviews
+        WHERE schemaname = '$schema'
+    ")"
+    for mview in $mviews ; do
+        echo -n "    $mview "
+        $psql -c "ALTER MATERIALIZED VIEW \"$schema\".\"$mview\" OWNER TO $new_owner"
+    done
+
+    echo "Reassigning foreign tables…"
+    ftables="$($psql -qAt -c "
+        SELECT table_name
+        FROM information_schema.tables
+        WHERE table_schema = '$schema' AND table_type = 'FOREIGN'
+    ")"
+    for ftable in $ftables ; do
+        echo -n "    $ftable "
+        $psql -c "ALTER FOREIGN TABLE \"$schema\".\"$ftable\" OWNER TO $new_owner"
+    done
+
+done # end of schema loop
+
+# Foreign servers.
+# Comment/uncomment the paragraph below if you want to reassign foreign servers
+# as well. Foreign data wrappers owners are not reassigned because PostgreSQL
+# requires a superuser to own them.
+
+echo "Reassigning foreign servers…"
+fservers="$($psql -qAt -c "
+    SELECT foreign_server_name
+    FROM information_schema.foreign_servers
+")"
+for fserver in $fservers ; do
+    echo -n "    $fserver "
+    $psql -c "ALTER SERVER $fserver OWNER TO $new_owner"
+done