external
/
citus
mirror of https://github.com/citusdata/citus.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add more comments

support-partitioning-for-citus-local-tables
Ahmet Gedemenli 2021-08-18 11:55:20 +03:00
parent e95022b737
commit c71f26524b
1 changed files with 21 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
src/backend/distributed/commands/citus_add_local_table_to_metadata.c
View File

@ -340,6 +340,14 @@ CreateCitusLocalTable(Oid relationId, bool cascadeViaForeignKeys)
/*
* CreateChildLocalTablesIfRelationIsPartitioned takes a relation id and creates
* Citus Local Tables for its partitions, if it's a partitioned table.
* Here we have two parameters: shellRelationId is the id of the partitioned shell table.
* shardRelationId is the partitioned table which has the shard_id suffix appended.
* In this function, while creating Citus Local Tables from partition (child) tables,
* the partition (child) shard tables successfully gets attached to the partitioned
* (parent) shard table, since there is already a parent/child relationship between them.
* However, the partition (child) shell tables are not attached to the partitioned
* (parent) shell tables. So we need to generate and execute commands for DETACH +
* ATTACH to establish the correct relationship.
*/
static void
CreateChildLocalTablesIfRelationIsPartitioned(Oid shellRelationId, Oid shardRelationId)
@ -357,12 +365,23 @@ CreateChildLocalTablesIfRelationIsPartitioned(Oid shellRelationId, Oid shardRela
* ALTER TABLE .. ATTACH PARTITION .., for attaching the shell child to the
* shell parent later.
*/
char *qualifiedShellRelationName = generate_qualified_relation_name(
shellRelationId);
char *qualifiedShellRelationName =
generate_qualified_relation_name(shellRelationId);
char *attachToParentCommand =
GenerateAlterTableAttachPartitionToParentCommand(partitionRelationId,
qualifiedShellRelationName);
/* here we call CreateCitusLocalTable for all partitions */
CreateCitusLocalTable(partitionRelationId, false);
/*
* CreateCitusLocalTable has created a Citus Local Table for the partition.
* It does this by renaming the partition and adding a shard_id suffix to it.
* This process leaves a shell table behind, which is NOT attached to the
* parent shell table. Here we basically DETACH + ATTACH it and make sure
* that the correct parent/child relationship is established between the
* parent/child shell tables.
*/
char *detachPartitionCommand = GenerateDetachPartitionCommand(
partitionRelationId);
ExecuteAndLogUtilityCommandList(list_make2(detachPartitionCommand,