Record if any partitioned Citus tables during upgrade (#5555)

With Citus 11, the default behavior is to sync the metadata.
However, partitioned tables created pre-Citus 11 might have
index names that are not compatiable with metadata syncing.

See https://github.com/citusdata/citus/issues/4962 for the
details.

With this commit, we record the existence of partitioned tables
such that we can fix it later if any exists.

src/backend/distributed/sql/citus--10.2-4--11.0-1.sql

@@ -30,3 +30,17 @@ BEGIN
 	END IF;
 END;
 $$;
+
+-- Here we keep track of partitioned tables that exists before Citus 11
+-- where we need to call fix_all_partition_shard_index_names() before
+-- metadata is synced. Note that after citus-11, we automatically
+-- adjust the indexes so we only need to fix existing indexes
+DO LANGUAGE plpgsql
+$$
+DECLARE
+  partitioned_table_exists bool :=false;
+BEGIN
+      SELECT count(*) > 0 INTO partitioned_table_exists FROM pg_dist_partition p JOIN pg_class c ON p.logicalrelid = c.oid WHERE c.relkind = 'p';
+      UPDATE pg_dist_node_metadata SET metadata=jsonb_set(metadata, '{partitioned_citus_table_exists_pre_11}', to_jsonb(partitioned_table_exists), true);
+END;
+$$;

src/test/regress/expected/multi_extension.out

@@ -955,8 +955,35 @@ ERROR:  cstore_fdw tables are deprecated as of Citus 11.0
 HINT:  Install Citus 10.2 and convert your cstore_fdw tables to the columnar access method before upgrading further
 CONTEXT:  PL/pgSQL function inline_code_block line XX at RAISE
 DELETE FROM pg_dist_shard WHERE shardid = 1;
+-- partitioned table count is tracked on Citus 11 upgrade
+CREATE TABLE e_transactions(order_id varchar(255) NULL, transaction_id int) PARTITION BY LIST(transaction_id);
+CREATE TABLE orders_2020_07_01
+PARTITION OF e_transactions FOR VALUES IN (1,2,3);
+INSERT INTO pg_dist_partition VALUES ('e_transactions'::regclass,'h', NULL, 7, 's');
+SELECT
+	(metadata->>'partitioned_citus_table_exists_pre_11')::boolean as partitioned_citus_table_exists_pre_11,
+	(metadata->>'partitioned_citus_table_exists_pre_11') IS NULL as is_null
+FROM
+	pg_dist_node_metadata;
+ partitioned_citus_table_exists_pre_11 | is_null
+---------------------------------------------------------------------
+                                       | t
+(1 row)
+
 -- Test downgrade to 10.2-4 from 11.0-1
 ALTER EXTENSION citus UPDATE TO '11.0-1';
+SELECT
+	(metadata->>'partitioned_citus_table_exists_pre_11')::boolean as partitioned_citus_table_exists_pre_11,
+	(metadata->>'partitioned_citus_table_exists_pre_11') IS NULL as is_null
+FROM
+	pg_dist_node_metadata;
+ partitioned_citus_table_exists_pre_11 | is_null
+---------------------------------------------------------------------
+ t                                     | f
+(1 row)
+
+DELETE FROM pg_dist_partition WHERE logicalrelid = 'e_transactions'::regclass;
+DROP TABLE e_transactions;
 ALTER EXTENSION citus UPDATE TO '10.2-4';
 -- Should be empty result since upgrade+downgrade should be a no-op
 SELECT * FROM multi_extension.print_extension_changes();

src/test/regress/sql/multi_extension.sql

@@ -420,8 +420,30 @@ INSERT INTO pg_dist_shard (logicalrelid, shardid, shardstorage) VALUES ('pg_dist
 ALTER EXTENSION citus UPDATE TO '11.0-1';
 DELETE FROM pg_dist_shard WHERE shardid = 1;
 
+-- partitioned table count is tracked on Citus 11 upgrade
+CREATE TABLE e_transactions(order_id varchar(255) NULL, transaction_id int) PARTITION BY LIST(transaction_id);
+CREATE TABLE orders_2020_07_01
+PARTITION OF e_transactions FOR VALUES IN (1,2,3);
+INSERT INTO pg_dist_partition VALUES ('e_transactions'::regclass,'h', NULL, 7, 's');
+
+SELECT
+	(metadata->>'partitioned_citus_table_exists_pre_11')::boolean as partitioned_citus_table_exists_pre_11,
+	(metadata->>'partitioned_citus_table_exists_pre_11') IS NULL as is_null
+FROM
+	pg_dist_node_metadata;
+
 -- Test downgrade to 10.2-4 from 11.0-1
 ALTER EXTENSION citus UPDATE TO '11.0-1';
+
+SELECT
+	(metadata->>'partitioned_citus_table_exists_pre_11')::boolean as partitioned_citus_table_exists_pre_11,
+	(metadata->>'partitioned_citus_table_exists_pre_11') IS NULL as is_null
+FROM
+	pg_dist_node_metadata;
+
+DELETE FROM pg_dist_partition WHERE logicalrelid = 'e_transactions'::regclass;
+DROP TABLE e_transactions;
+
 ALTER EXTENSION citus UPDATE TO '10.2-4';
 -- Should be empty result since upgrade+downgrade should be a no-op
 SELECT * FROM multi_extension.print_extension_changes();