/*
* create_distributed_table gets a table name, distribution column,
* distribution method and colocate_with option, then it creates a
* distributed table.
*/
Datum
create_distributed_table(PG_FUNCTION_ARGS)
{
Oid relationId = InvalidOid;
text *distributionColumnText = NULL;
Oid distributionMethodOid = InvalidOid;
text *colocateWithTableNameText = NULL;
Relation relation = NULL;
char *distributionColumnName = NULL;
Var *distributionColumn = NULL;
char distributionMethod = 0;
char *colocateWithTableName = NULL;
bool viaDeprecatedAPI = false;
CheckCitusVersion(ERROR);
EnsureCoordinator();
relationId = PG_GETARG_OID(0);
distributionColumnText = PG_GETARG_TEXT_P(1);
distributionMethodOid = PG_GETARG_OID(2);
colocateWithTableNameText = PG_GETARG_TEXT_P(3);
/*
* 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 = try_relation_open(relationId, ExclusiveLock);
if (relation == NULL)
{
ereport(ERROR, (errmsg("could not create distributed table: "
"relation does not exist")));
}
/*
* We should do this check here since the codes in the following lines rely
* on this relation to have a supported relation kind. More extensive checks
* will be performed in CreateDistributedTable.
*/
EnsureRelationKindSupported(relationId);
distributionColumnName = text_to_cstring(distributionColumnText);
distributionColumn = BuildDistributionKeyFromColumnName(relation,
distributionColumnName);
distributionMethod = LookupDistributionMethod(distributionMethodOid);
colocateWithTableName = text_to_cstring(colocateWithTableNameText);
CreateDistributedTable(relationId, distributionColumn, distributionMethod,
colocateWithTableName, viaDeprecatedAPI);
relation_close(relation, NoLock);
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);
}
}