extern void PoolPingNodes(void);
+
+/* Determine if given function is shippable */
+static bool pgxc_is_func_shippable(Oid funcid);
+/* Check equijoin conditions on given relations */
+static Expr *pgxc_find_dist_equijoin_qual(Relids varnos_1, Relids varnos_2,
+ Oid distcol_type, Node *quals, List *rtable);
+/* Merge given execution nodes based on join shippability conditions */
+static ExecNodes *pgxc_merge_exec_nodes(ExecNodes *en1, ExecNodes *en2);
+/* Check if given Query includes distribution column */
+static bool pgxc_query_has_distcolgrouping(Query *query);
+
/* Manipulation of shippability reason */
static bool pgxc_test_shippability_reason(Shippability_context *context,
ShippabilityStat reason);
return rel_exec_nodes;
}
-bool
+static bool
pgxc_query_has_distcolgrouping(Query *query)
{
ListCell *lcell;
* pgxc_is_func_shippable
* Determine if a function is shippable
*/
-bool
+static bool
pgxc_is_func_shippable(Oid funcid)
{
/*
* pgxc_find_dist_equijoin_qual
* Check equijoin conditions on given relations
*/
-Expr *
+static Expr *
pgxc_find_dist_equijoin_qual(Relids varnos_1,
Relids varnos_2, Oid distcol_type, Node *quals, List *rtable)
{
* exec_node corresponds to the JOIN of respective relations.
* If both exec_nodes can not be merged, it returns NULL.
*/
-ExecNodes *
+static ExecNodes *
pgxc_merge_exec_nodes(ExecNodes *en1, ExecNodes *en2)
{
ExecNodes *merged_en = makeNode(ExecNodes);
}
-/*
- * pgxc_check_index_shippability
- * Check shippability of index described by given conditions. This generic
- * function can be called even if the index is not yet defined.
- */
-bool
-pgxc_check_index_shippability(RelationLocInfo *relLocInfo,
- bool is_primary,
- bool is_unique,
- bool is_exclusion,
- List *indexAttrs,
- List *indexExprs)
-{
- bool result = true;
- ListCell *lc;
-
- /*
- * Leave if no locator information, in this case shippability has no
- * meaning.
- */
- if (!relLocInfo)
- return result;
-
- /*
- * Scan the expressions used in index and check the shippability of each
- * of them. If only one is not-shippable, the index is considered as non
- * shippable. It is important to check the shippability of the expressions
- * before refining scan on the index columns and distribution type of
- * parent relation.
- */
- foreach(lc, indexExprs)
- {
- if (!pgxc_is_expr_shippable((Expr *) lfirst(lc), NULL))
- {
- /* One of the expressions is not shippable, so leave */
- result = false;
- goto finish;
- }
- }
-
- /*
- * Check if relation is distributed on a single node, in this case
- * the constraint can be shipped in all the cases.
- */
- if (list_length(relLocInfo->rl_nodeList) == 1)
- return result;
-
- /*
- * Check the case of EXCLUSION index.
- * EXCLUSION constraints are shippable only for replicated relations as
- * such constraints need that one tuple is checked on all the others, and
- * if this tuple is correctly excluded of the others, the constraint is
- * verified.
- */
- if (is_exclusion)
- {
- if (!IsRelationReplicated(relLocInfo))
- {
- result = false;
- goto finish;
- }
- }
-
- /*
- * Check the case of PRIMARY KEY INDEX and UNIQUE index.
- * Those constraints are shippable if the parent relation is replicated
- * or if the column
- */
- if (is_unique ||
- is_primary)
- {
- /*
- * Perform different checks depending on distribution type of parent
- * relation.
- */
- switch(relLocInfo->locatorType)
- {
- case LOCATOR_TYPE_REPLICATED:
- /* In the replicated case this index is shippable */
- result = true;
- break;
-
- case LOCATOR_TYPE_RROBIN:
- /*
- * Index on roundrobin parent table cannot be safely shipped
- * because of the random behavior of data balancing.
- */
- result = false;
- break;
-
- case LOCATOR_TYPE_HASH:
- case LOCATOR_TYPE_MODULO:
- /*
- * Unique indexes on Hash and Modulo tables are shippable if the
- * index expression contains all the distribution expressions of
- * its parent relation.
- *
- * Here is a short example with concatenate that cannot be
- * shipped:
- * CREATE TABLE aa (a text, b text) DISTRIBUTE BY HASH(a);
- * CREATE UNIQUE INDEX aap ON aa((a || b));
- * INSERT INTO aa VALUES ('a', 'abb');
- * INSERT INTO aa VALUES ('aab', b); -- no error ??!
- * The output uniqueness is not guaranteed as both INSERT will
- * go to different nodes. For such simple reasons unique
- * indexes on distributed tables are not shippable.
- * Shippability is not even ensured if all the expressions
- * used as Var are only distributed columns as the hash output of
- * their value combination does not ensure that query will
- * be directed to the correct remote node. Uniqueness is not even
- * protected if the index expression contains only the distribution
- * column like for that with a cluster of 2 Datanodes:
- * CREATE TABLE aa (a int) DISTRIBUTE BY HASH(a);
- * CREATE UNIQUE INDEX aap ON (abs(a));
- * INSERT INTO aa (2); -- to Datanode 1
- * INSERT INTO aa (-2); -- to Datanode 2, breaks uniqueness
- *
- * PGXCTODO: for the time being distribution key can only be
- * defined on a single column, so this will need to be changed
- * onde a relation distribution will be able to be defined based
- * on an expression of multiple columns.
- */
-
- /* Index contains expressions, it cannot be shipped safely */
- if (indexExprs != NIL)
- {
- result = false;
- break;
- }
-
- /* Nothing to do if no attributes */
- if (indexAttrs == NIL)
- break;
-
- /*
- * Check that distribution column is included in the list of
- * index columns.
- */
- if (!list_member_int(indexAttrs, relLocInfo->partAttrNum))
- {
- /*
- * Distribution column is not in index column list
- * So index can be enforced remotely.
- */
- result = false;
- break;
- }
-
- /*
- * by being here we are now sure that the index can be enforced
- * remotely as the distribution column is included in index.
- */
- break;
-
- /* Those types are not supported yet */
- case LOCATOR_TYPE_RANGE:
- case LOCATOR_TYPE_NONE:
- case LOCATOR_TYPE_DISTRIBUTED:
- case LOCATOR_TYPE_CUSTOM:
- default:
- /* Should not come here */
- Assert(0);
- }
- }
-
-finish:
- return result;
-}
-
-
-/*
- * pgxc_check_fk_shippabilily
- * Check the shippability of a parent and a child relation based on the
- * distribution of each and the columns that are used to reference to
- * parent and child relation. This can be used for inheritance or foreign
- * key shippability evaluation.
- */
-bool
-pgxc_check_fk_shippability(RelationLocInfo *parentLocInfo,
- RelationLocInfo *childLocInfo,
- List *parentRefs,
- List *childRefs)
-{
- bool result = true;
-
- Assert(list_length(parentRefs) == list_length(childRefs));
-
- /*
- * If either child or parent have no relation data, shippability makes
- * no sense.
- */
- if (!parentLocInfo || !childLocInfo)
- return result;
-
- /* In the case of a child referencing to itself, constraint is shippable */
- if (IsLocatorInfoEqual(parentLocInfo, childLocInfo))
- return result;
-
- /* Now begin the evaluation */
- switch (parentLocInfo->locatorType)
- {
- case LOCATOR_TYPE_REPLICATED:
- /*
- * If the parent relation is replicated, the child relation can
- * always refer to it on all the nodes.
- */
- result = true;
- break;
-
- case LOCATOR_TYPE_RROBIN:
- /*
- * If the parent relation is based on roundrobin, the child
- * relation cannot be enforced on remote nodes before of the
- * random behavior of data balancing.
- */
- result = false;
- break;
-
- case LOCATOR_TYPE_HASH:
- case LOCATOR_TYPE_MODULO:
- /*
- * If parent table is distributed, the child table can reference
- * to its parent safely if the following conditions are satisfied:
- * - parent and child are both hash-based, or both modulo-based
- * - parent reference columns contain the distribution column
- * of the parent relation
- * - child reference columns contain the distribution column
- * of the child relation
- * - both child and parent map the same nodes for data location
- */
-
- /* A replicated child cannot refer to a distributed parent */
- if (IsRelationReplicated(childLocInfo))
- {
- result = false;
- break;
- }
-
- /*
- * Parent and child need to have the same distribution type:
- * hash or modulo.
- */
- if (parentLocInfo->locatorType != childLocInfo->locatorType)
- {
- result = false;
- break;
- }
-
- /*
- * Parent and child need to have their data located exactly
- * on the same list of nodes.
- */
- if (list_difference_int(childLocInfo->rl_nodeList, parentLocInfo->rl_nodeList) ||
- list_difference_int(parentLocInfo->rl_nodeList, childLocInfo->rl_nodeList))
- {
- result = false;
- break;
- }
-
- /*
- * Check that child and parents are referenced using their
- * distribution column.
- */
- if (!list_member_int(childRefs, childLocInfo->partAttrNum) ||
- !list_member_int(parentRefs, parentLocInfo->partAttrNum))
- {
- result = false;
- break;
- }
-
- /* By being here, parent-child constraint can be shipped correctly */
- break;
-
- case LOCATOR_TYPE_RANGE:
- case LOCATOR_TYPE_NONE:
- case LOCATOR_TYPE_DISTRIBUTED:
- case LOCATOR_TYPE_CUSTOM:
- default:
- /* Should not come here */
- Assert(0);
- }
-
- return result;
-}
-
/*
* pgxc_is_join_reducible
* The shippability of JOIN is decided in following steps
projects / postgres-xl.git / commitdiff