I am running Postgres 10.X, and I am using pg_partman for managing my partitions.
Here is a simplified structure:
db=> \d+ my_table_partitioned_template
Table "public.my_table_partitioned_template"
Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
--------------------------------+-----------------------------+-----------+----------+---------+----------+--------------+-------------
id | integer | | not null | | plain | |
creation_time | timestamp without time zone | | | | plain |
special_id | integer | | | | plain | |
Indexes:
"my_table_partitioned_template_pkey" PRIMARY KEY, btree (id)
"ix_my_table_partitioned_template_sensor_id" btree (sensor_id)
Foreign-key constraints:
"my_table_partitioned_template_sensor_id_fkey" FOREIGN KEY (sensor_id) REFERENCES sensor(id) ON DELETE CASCADE
db=> \d+ my_table_partitioned
Table "public.my_table_partitioned"
Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
--------------------------------+-----------------------------+-----------+----------+---------+----------+--------------+-------------
id | integer | | not null | | plain | |
creation_time | timestamp without time zone | | | | plain |
special_id | integer | | | | plain | |
Partition key: RANGE (creation_time)
Partitions: my_table_partitioned_p2019_04_17 FOR VALUES FROM ('2019-04-17 00:00:00') TO ('2019-04-24 00:00:00'),
my_table_partitioned_p2019_04_24 FOR VALUES FROM ('2019-04-24 00:00:00') TO ('2019-05-01 00:00:00'),
my_table_partitioned_p2019_05_01 FOR VALUES FROM ('2019-05-01 00:00:00') TO ('2019-05-08 00:00:00'),
my_table_partitioned_p2019_05_08 FOR VALUES FROM ('2019-05-08 00:00:00') TO ('2019-05-15 00:00:00'),
my_table_partitioned_p2019_05_15 FOR VALUES FROM ('2019-05-15 00:00:00') TO ('2019-05-22 00:00:00')
pg_partman, once in a while wakes up and apply the partitions configuration, which means adding new ones and dropping old ones.
During that maintenance time, most of my database queries are in Locked state.
I would expect queries on my_table_partitioned to be blocked, because of a DROP TABLE statements going on. But what I don't understand is why queries on sensor table are being locked.
Can it be because the partitioned table has a foreign key to that table?
What am I missing?
Thanks,
Tomer
