Extend postgres_indexes view

This adds boolean columns to indicate an index is partial or an
expression index.

changelogs/unreleased/ab-reindex-functional.yml

+---
+title: Expand postgres_indexes view
+merge_request: 47304
+author:
+type: other

db/migrate/20201110110454_extend_postgres_indexes_view.rb

+# frozen_string_literal: true
+
+class ExtendPostgresIndexesView < ActiveRecord::Migration[6.0]
+  DOWNTIME = false
+
+  def up
+    execute(<<~SQL)
+      DROP VIEW postgres_indexes;
+
+      CREATE VIEW postgres_indexes AS
+      SELECT (pg_namespace.nspname::text || '.'::text) || pg_class.relname::text AS identifier,
+        pg_index.indexrelid,
+        pg_namespace.nspname AS schema,
+        pg_class.relname AS name,
+        pg_index.indisunique AS "unique",
+        pg_index.indisvalid AS valid_index,
+        pg_class.relispartition AS partitioned,
+        pg_index.indisexclusion AS exclusion,
+        pg_index.indexprs IS NOT NULL as expression,
+        pg_index.indpred IS NOT NULL as partial,
+        pg_indexes.indexdef AS definition,
+        pg_relation_size(pg_class.oid::regclass) AS ondisk_size_bytes
+      FROM pg_index
+        JOIN pg_class ON pg_class.oid = pg_index.indexrelid
+        JOIN pg_namespace ON pg_class.relnamespace = pg_namespace.oid
+        JOIN pg_indexes ON pg_class.relname = pg_indexes.indexname
+      WHERE pg_namespace.nspname <> 'pg_catalog'::name
+        AND (pg_namespace.nspname = ANY (ARRAY["current_schema"(), 'gitlab_partitions_dynamic'::name, 'gitlab_partitions_static'::name]));
+    SQL
+  end
+
+  def down
+    execute(<<~SQL)
+      DROP VIEW postgres_indexes;
+
+      CREATE VIEW postgres_indexes AS
+      SELECT (pg_namespace.nspname::text || '.'::text) || pg_class.relname::text AS identifier,
+        pg_index.indexrelid,
+        pg_namespace.nspname AS schema,
+        pg_class.relname AS name,
+        pg_index.indisunique AS "unique",
+        pg_index.indisvalid AS valid_index,
+        pg_class.relispartition AS partitioned,
+        pg_index.indisexclusion AS exclusion,
+        pg_indexes.indexdef AS definition,
+        pg_relation_size(pg_class.oid::regclass) AS ondisk_size_bytes
+      FROM pg_index
+        JOIN pg_class ON pg_class.oid = pg_index.indexrelid
+        JOIN pg_namespace ON pg_class.relnamespace = pg_namespace.oid
+        JOIN pg_indexes ON pg_class.relname = pg_indexes.indexname
+      WHERE pg_namespace.nspname <> 'pg_catalog'::name
+        AND (pg_namespace.nspname = ANY (ARRAY["current_schema"(), 'gitlab_partitions_dynamic'::name, 'gitlab_partitions_static'::name]));
+    SQL
+  end
+end

db/schema_migrations/20201110110454

+f008d77d2a0aef463a924923d5a338030758d6b9c194756a0490b51a95681127
\ No newline at end of file

db/structure.sql

@@ -14722,6 +14722,8 @@ CREATE VIEW postgres_indexes AS
     pg_index.indisvalid AS valid_index,
     pg_class.relispartition AS partitioned,
     pg_index.indisexclusion AS exclusion,
+    (pg_index.indexprs IS NOT NULL) AS expression,
+    (pg_index.indpred IS NOT NULL) AS partial,
     pg_indexes.indexdef AS definition,
     pg_relation_size((pg_class.oid)::regclass) AS ondisk_size_bytes
    FROM (((pg_index