Fixes#78
With this change, it is possible to append a table in any schema to shard. The function
master_append_table_to_shard now supports schema names.
Now, master_create_empty_shard() will create shards according to the
value of citus.shard_placement_policy which also makes default round-robin
instead of random.
Fixes#10
This change creates a new UDF: master_modify_multiple_shards
Parameters:
modify_query: A simple DELETE or UPDATE query as a string.
The UDF is similar to the existing master_apply_delete_command UDF.
Basically, given the modify query, it prunes the shard list, re-constructs
the query for each shard and sends the query to the placements.
Depending on the value of citus.multi_shard_commit_protocol, the commit
can be done in one-phase or two-phase manner.
Limitations:
* It cannot be called inside a transaction block
* It only be called with simple operator expressions (like Single Shard Modify)
Sample Usage:
```
SELECT master_modify_multiple_shards(
'DELETE FROM customer_delete_protocol WHERE c_custkey > 500 AND c_custkey < 500');
```
Now, we can copy to an append-partitioned distributed relation from
any worker node by providing master options such as;
COPY relation_name FROM file_path WITH (delimiter '|', master_host 'localhost', master_port 5432);
where master_port is optional and default is 5432.
That's important because ownership of relations implies special
privileges. Without this change, a distributed table can be accessible
by a table's owner, but a shard created by another user might not.
- Flexed the check which prevented append operation cstore tables
since its storage type is not SHARD_STORAGE_TABLE.
- Used process utility function to perform copy operation in
worker_append_table_to shard() instead of directly calling
postgresql DoCopy().
- Removed the additional check in master_create_empty_shard() function.
This check was redundant and erroneous since it was called after
CheckDistributedTable() call.
- Modified WorkerTableSize() function to retrieve cstore table shard
size correctly.
After this change, shards and associated metadata are automatically
dropped when running DROP TABLE on a distributed table, which fixes#230.
It also adds schema support for master_apply_delete_command, which
fixes#73.
Dropping the shards happens in the master_drop_all_shards UDF, which is
called from the SQL_DROP trigger. Inside the trigger, the table is no
longer visible and calling master_apply_delete_command directly wouldn't
work and oid <-> name mappings are not available. The
master_drop_all_shards function therefore takes the relation id, schema
name, and table name as parameters, which can be obtained from
pg_event_trigger_dropped_objects() in the SQL_DROP trigger. If the user
calls master_drop_all_shards while the table still exists, the schema
name and table name are ignored.
Author: Marco Slot
Reviewed-By: Andres Freund
Burak Yucesoy
Metin Doslu
eren
Andres Freund
Jason Petersen
Marco Slot
Murat Tuncer
Murat Tuncer
Onder Kalaci