/*
* CreateDistributedTable creates distributed table in the given configuration.
* This functions contains all necessary logic to create distributed tables. It
* perform necessary checks to ensure distributing the table is safe. If it is
* safe to distribute the table, this function creates distributed table metadata,
* creates shards and copies local data to shards. This function also handles
* partitioned tables by distributing its partitions as well.
*
* viaDeprecatedAPI boolean flag is not optimal way to implement this function,
* but it helps reducing code duplication a lot. We hope to remove that flag one
* day, once we deprecate master_create_distribute_table completely.
*/
void
CreateDistributedTable(Oid relationId, Var *distributionColumn, char distributionMethod,
char *colocateWithTableName, bool viaDeprecatedAPI)
{
char replicationModel = REPLICATION_MODEL_INVALID;
uint32 colocationId = INVALID_COLOCATION_ID;
Oid colocatedTableId = InvalidOid;
bool localTableEmpty = false;
Relation colocatedRelation = NULL;
replicationModel = AppropriateReplicationModel(distributionMethod, viaDeprecatedAPI);
/*
* ColocationIdForNewTable assumes caller acquires lock on relationId. In our case,
* our caller already acquired lock on relationId.
*/
colocationId = ColocationIdForNewTable(relationId, distributionColumn,
distributionMethod, replicationModel,
colocateWithTableName, viaDeprecatedAPI);
EnsureRelationCanBeDistributed(relationId, distributionColumn, distributionMethod,
colocationId, replicationModel, viaDeprecatedAPI);
/* we need to calculate these variables before creating distributed metadata */
localTableEmpty = LocalTableEmpty(relationId);
colocatedTableId = ColocatedTableId(colocationId);
/* create an entry for distributed table in pg_dist_partition */
InsertIntoPgDistPartition(relationId, distributionMethod, distributionColumn,
colocationId, replicationModel);
/* foreign tables does not support TRUNCATE trigger */
if (RegularTable(relationId))
{
CreateTruncateTrigger(relationId);
}
/*
* If we are using master_create_distributed_table, we don't need to continue,
* because deprecated API does not supports the following features.
*/
if (viaDeprecatedAPI)
{
/*
* We exit early but there is no need to close colocatedRelation. Because
* if viaDeprecatedAPI is true, we never open colocatedRelation in the first
* place.
*/
Assert(colocatedRelation == NULL);
return;
}
/* create shards for hash distributed and reference tables */
if (distributionMethod == DISTRIBUTE_BY_HASH)
{
CreateHashDistributedTableShards(relationId, colocatedTableId, localTableEmpty);
}
else if (distributionMethod == DISTRIBUTE_BY_NONE)
{
CreateReferenceTableShard(relationId);
}
if (ShouldSyncTableMetadata(relationId))
{
CreateTableMetadataOnWorkers(relationId);
}
/*
* We've a custom way of foreign key graph invalidation,
* see InvalidateForeignKeyGraph().
*/
if (TableReferenced(relationId) || TableReferencing(relationId))
{
InvalidateForeignKeyGraph();
}
/* if this table is partitioned table, distribute its partitions too */
if (PartitionedTable(relationId))
{
List *partitionList = PartitionList(relationId);
ListCell *partitionCell = NULL;
foreach(partitionCell, partitionList)
{
Oid partitionRelationId = lfirst_oid(partitionCell);
CreateDistributedTable(partitionRelationId, distributionColumn,
distributionMethod, colocateWithTableName,
viaDeprecatedAPI);
}
}
/*
* ConvertToDistributedTable converts the given regular PostgreSQL table into a
* distributed table. First, it checks if the given table can be distributed,
* then it creates related tuple in pg_dist_partition.
*
* XXX: We should perform more checks here to see if this table is fit for
* partitioning. At a minimum, we should validate the following: (i) this node
* runs as the master node, (ii) table does not make use of the inheritance
* mechanism, (iii) table does not own columns that are sequences, and (iv)
* table does not have collated columns.
*/
static void
ConvertToDistributedTable(Oid relationId, char *distributionColumnName,
char distributionMethod, uint32 colocationId)
{
Relation relation = NULL;
TupleDesc relationDesc = NULL;
char *relationName = NULL;
char relationKind = 0;
Var *distributionColumn = NULL;
/*
* Lock target relation with an exclusive lock - there's no way to make
* sense of this table until we've committed, and we don't want multiple
* backends manipulating this relation.
*/
relation = relation_open(relationId, ExclusiveLock);
relationDesc = RelationGetDescr(relation);
relationName = RelationGetRelationName(relation);
EnsureTableOwner(relationId);
/* check that the relation is not already distributed */
if (IsDistributedTable(relationId))
{
ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("table \"%s\" is already distributed",
relationName)));
}
/* verify target relation does not use WITH (OIDS) PostgreSQL feature */
if (relationDesc->tdhasoid)
{
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot distribute relation: %s", relationName),
errdetail("Distributed relations must not specify the WITH "
"(OIDS) option in their definitions.")));
}
/* verify target relation is either regular or foreign table */
relationKind = relation->rd_rel->relkind;
if (relationKind != RELKIND_RELATION && relationKind != RELKIND_FOREIGN_TABLE)
{
ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot distribute relation: %s",
relationName),
errdetail("Distributed relations must be regular or "
"foreign tables.")));
}
/* check that the relation does not contain any rows */
if (!LocalTableEmpty(relationId))
{
ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot distribute relation \"%s\"",
relationName),
errdetail("Relation \"%s\" contains data.",
relationName),
errhint("Empty your table before distributing it.")));
}
distributionColumn = BuildDistributionKeyFromColumnName(relation,
distributionColumnName);
/* check for support function needed by specified partition method */
if (distributionMethod == DISTRIBUTE_BY_HASH)
{
Oid hashSupportFunction = SupportFunctionForColumn(distributionColumn,
HASH_AM_OID, HASHPROC);
if (hashSupportFunction == InvalidOid)
{
ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("could not identify a hash function for type %s",
format_type_be(distributionColumn->vartype)),
errdatatype(distributionColumn->vartype),
errdetail("Partition column types must have a hash function "
"defined to use hash partitioning.")));
}
}
else if (distributionMethod == DISTRIBUTE_BY_RANGE)
{
Oid btreeSupportFunction = SupportFunctionForColumn(distributionColumn,
BTREE_AM_OID, BTORDER_PROC);
if (btreeSupportFunction == InvalidOid)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("could not identify a comparison function for type %s",
format_type_be(distributionColumn->vartype)),
errdatatype(distributionColumn->vartype),
errdetail("Partition column types must have a comparison function "
"defined to use range partitioning.")));
}
}
ErrorIfNotSupportedConstraint(relation, distributionMethod, distributionColumn,
colocationId);
InsertIntoPgDistPartition(relationId, distributionMethod, distributionColumn,
colocationId);
relation_close(relation, NoLock);
/*
* PostgreSQL supports truncate trigger for regular relations only.
* Truncate on foreign tables is not supported.
*/
if (relationKind == RELKIND_RELATION)
{
CreateTruncateTrigger(relationId);
}
}