This commit is preperation for introducing distributed partitioned
table support. We want to clean and refactor some code in distributed
table creation logic so that we can handle partitioned tables in more
robust way.
- master_add_node enforces that there is only one primary per group
- there's also a trigger on pg_dist_node to prevent multiple primaries
per group
- functions in metadata cache only return primary nodes
- Rename ActiveWorkerNodeList -> ActivePrimaryNodeList
- Rename WorkerGetLive{Node->Group}Count()
- Refactor WorkerGetRandomCandidateNode
- master_remove_node only complains about active shard placements if the
node being removed is a primary.
- master_remove_node only deletes all reference table placements in the
group if the node being removed is the primary.
- Rename {Node->NodeGroup}HasShardPlacements, this reflects the behavior it
already had.
- Rename DeleteAllReferenceTablePlacementsFrom{Node->NodeGroup}. This also
reflects the behavior it already had, but the new signature forces the
caller to pass in a groupId
- Rename {WorkerGetLiveGroup->ActivePrimaryNode}Count
With this change we add an option to add a node without replicating all reference
tables to that node. If a node is added with this option, we mark the node as
inactive and no queries will sent to that node.
We also added two new UDFs;
- master_activate_node(host, port):
- marks node as active and replicates all reference tables to that node
- master_add_inactive_node(host, port):
- only adds node to pg_dist_node
related to a table that might be distributed, allowing any name
that is within regular PostgreSQL length limits to be extended
with a shard ID for use in shards on workers. Handles multi-byte
character boundaries in identifiers when making prefixes for
shard-extended names. Includes tests.
Uses hash_any from PostgreSQL's access/hashfunc.c.
Removes AppendShardIdToStringInfo() as it's used only once
and arguably is best replaced there with a call to AppendShardIdToName().
Adds UDF shard_name(object_name, shard_id) to expose the shard-extended
name logic to other PL/PGSQL, UDFs and scripts.
Bumps version to 6.0-2 to allow for UDF to be created in migration script.
Fixescitusdata/citus#781 and citusdata/citus#179.
Burak Yucesoy
Brian Cloutier
velioglu
Önder Kalacı
Marco Slot
Robin Thomas
Murat Tuncer