/*
* master_create_distributed_table inserts the table and partition column
* information into the partition metadata table. Note that this function
* currently assumes the table is hash partitioned.
*/
Datum
master_create_distributed_table(PG_FUNCTION_ARGS)
{
text *tableNameText = PG_GETARG_TEXT_P(0);
text *partitionColumnText = PG_GETARG_TEXT_P(1);
char partitionMethod = PG_GETARG_CHAR(2);
Oid distributedTableId = ResolveRelationId(tableNameText);
char relationKind = '\0';
char *partitionColumnName = text_to_cstring(partitionColumnText);
char *tableName = text_to_cstring(tableNameText);
Var *partitionColumn = NULL;
/* verify target relation is either regular or foreign table */
relationKind = get_rel_relkind(distributedTableId);
if (relationKind != RELKIND_RELATION && relationKind != RELKIND_FOREIGN_TABLE)
{
ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot distribute relation: %s", tableName),
errdetail("Distributed relations must be regular or "
"foreign tables.")));
}
/* this will error out if no column exists with the specified name */
partitionColumn = ColumnNameToColumn(distributedTableId, partitionColumnName);
/* check for support function needed by specified partition method */
if (partitionMethod == HASH_PARTITION_TYPE)
{
Oid hashSupportFunction = SupportFunctionForColumn(partitionColumn, 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(partitionColumn->vartype)),
errdatatype(partitionColumn->vartype),
errdetail("Partition column types must have a hash function "
"defined to use hash partitioning.")));
}
}
else if (partitionMethod == RANGE_PARTITION_TYPE)
{
Oid btreeSupportFunction = InvalidOid;
/*
* Error out immediately since we don't yet support range partitioning,
* but the checks below are ready for when we do.
*
* TODO: Remove when range partitioning is supported.
*/
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("pg_shard only supports hash partitioning")));
btreeSupportFunction = SupportFunctionForColumn(partitionColumn, 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(partitionColumn->vartype)),
errdatatype(partitionColumn->vartype),
errdetail("Partition column types must have a comparison function "
"defined to use range partitioning.")));
}
}
/* insert row into the partition metadata table */
InsertPartitionRow(distributedTableId, partitionMethod, partitionColumnText);
PG_RETURN_VOID();
}
/*
* 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);
}
}