diff options
Diffstat (limited to 'src/backend/optimizer/util/relnode.c')
| -rw-r--r-- | src/backend/optimizer/util/relnode.c | 279 |
1 files changed, 241 insertions, 38 deletions
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index 374f93890bd..af1fb486488 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -29,6 +29,7 @@ #include "optimizer/tlist.h" #include "partitioning/partbounds.h" #include "utils/hsearch.h" +#include "utils/lsyscache.h" typedef struct JoinHashEntry @@ -58,6 +59,14 @@ static void add_join_rel(PlannerInfo *root, RelOptInfo *joinrel); static void build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, RelOptInfo *inner_rel, List *restrictlist, JoinType jointype); +static bool have_partkey_equi_join(RelOptInfo *joinrel, + RelOptInfo *rel1, RelOptInfo *rel2, + JoinType jointype, List *restrictlist); +static int match_expr_to_partition_keys(Expr *expr, RelOptInfo *rel, + bool strict_op); +static void set_joinrel_partition_key_exprs(RelOptInfo *joinrel, + RelOptInfo *outer_rel, RelOptInfo *inner_rel, + JoinType jointype); static void build_child_join_reltarget(PlannerInfo *root, RelOptInfo *parentrel, RelOptInfo *childrel, @@ -1607,18 +1616,15 @@ find_param_path_info(RelOptInfo *rel, Relids required_outer) /* * build_joinrel_partition_info - * If the two relations have same partitioning scheme, their join may be - * partitioned and will follow the same partitioning scheme as the joining - * relations. Set the partition scheme and partition key expressions in - * the join relation. + * Checks if the two relations being joined can use partitionwise join + * and if yes, initialize partitioning information of the resulting + * partitioned join relation. */ static void build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, RelOptInfo *inner_rel, List *restrictlist, JoinType jointype) { - int partnatts; - int cnt; PartitionScheme part_scheme; /* Nothing to do if partitionwise join technique is disabled. */ @@ -1672,8 +1678,7 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, /* * This function will be called only once for each joinrel, hence it - * should not have partition scheme, partition bounds, partition key - * expressions and array for storing child relations set. + * should not have partitioning fields filled yet. */ Assert(!joinrel->part_scheme && !joinrel->partexprs && !joinrel->nullable_partexprs && !joinrel->part_rels && @@ -1685,11 +1690,10 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, */ joinrel->part_scheme = part_scheme; joinrel->boundinfo = outer_rel->boundinfo; - partnatts = joinrel->part_scheme->partnatts; - joinrel->partexprs = (List **) palloc0(sizeof(List *) * partnatts); - joinrel->nullable_partexprs = - (List **) palloc0(sizeof(List *) * partnatts); joinrel->nparts = outer_rel->nparts; + set_joinrel_partition_key_exprs(joinrel, outer_rel, inner_rel, jointype); + + /* part_rels[] will be filled later, but allocate it now */ joinrel->part_rels = (RelOptInfo **) palloc0(sizeof(RelOptInfo *) * joinrel->nparts); @@ -1699,34 +1703,205 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, Assert(outer_rel->consider_partitionwise_join); Assert(inner_rel->consider_partitionwise_join); joinrel->consider_partitionwise_join = true; +} + +/* + * have_partkey_equi_join + * + * Returns true if there exist equi-join conditions involving pairs + * of matching partition keys of the relations being joined for all + * partition keys. + */ +static bool +have_partkey_equi_join(RelOptInfo *joinrel, + RelOptInfo *rel1, RelOptInfo *rel2, + JoinType jointype, List *restrictlist) +{ + PartitionScheme part_scheme = rel1->part_scheme; + ListCell *lc; + int cnt_pks; + bool pk_has_clause[PARTITION_MAX_KEYS]; + bool strict_op; /* - * Construct partition keys for the join. - * - * An INNER join between two partitioned relations can be regarded as - * partitioned by either key expression. For example, A INNER JOIN B ON - * A.a = B.b can be regarded as partitioned on A.a or on B.b; they are - * equivalent. - * - * For a SEMI or ANTI join, the result can only be regarded as being - * partitioned in the same manner as the outer side, since the inner - * columns are not retained. - * - * An OUTER join like (A LEFT JOIN B ON A.a = B.b) may produce rows with - * B.b NULL. These rows may not fit the partitioning conditions imposed on - * B.b. Hence, strictly speaking, the join is not partitioned by B.b and - * thus partition keys of an OUTER join should include partition key - * expressions from the OUTER side only. However, because all - * commonly-used comparison operators are strict, the presence of nulls on - * the outer side doesn't cause any problem; they can't match anything at - * future join levels anyway. Therefore, we track two sets of - * expressions: those that authentically partition the relation - * (partexprs) and those that partition the relation with the exception - * that extra nulls may be present (nullable_partexprs). When the - * comparison operator is strict, the latter is just as good as the - * former. + * This function must only be called when the joined relations have same + * partitioning scheme. + */ + Assert(rel1->part_scheme == rel2->part_scheme); + Assert(part_scheme); + + memset(pk_has_clause, 0, sizeof(pk_has_clause)); + foreach(lc, restrictlist) + { + RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc); + OpExpr *opexpr; + Expr *expr1; + Expr *expr2; + int ipk1; + int ipk2; + + /* If processing an outer join, only use its own join clauses. */ + if (IS_OUTER_JOIN(jointype) && + RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids)) + continue; + + /* Skip clauses which can not be used for a join. */ + if (!rinfo->can_join) + continue; + + /* Skip clauses which are not equality conditions. */ + if (!rinfo->mergeopfamilies && !OidIsValid(rinfo->hashjoinoperator)) + continue; + + /* Should be OK to assume it's an OpExpr. */ + opexpr = castNode(OpExpr, rinfo->clause); + + /* Match the operands to the relation. */ + if (bms_is_subset(rinfo->left_relids, rel1->relids) && + bms_is_subset(rinfo->right_relids, rel2->relids)) + { + expr1 = linitial(opexpr->args); + expr2 = lsecond(opexpr->args); + } + else if (bms_is_subset(rinfo->left_relids, rel2->relids) && + bms_is_subset(rinfo->right_relids, rel1->relids)) + { + expr1 = lsecond(opexpr->args); + expr2 = linitial(opexpr->args); + } + else + continue; + + /* + * Now we need to know whether the join operator is strict; see + * comments in pathnodes.h. + */ + strict_op = op_strict(opexpr->opno); + + /* + * Only clauses referencing the partition keys are useful for + * partitionwise join. + */ + ipk1 = match_expr_to_partition_keys(expr1, rel1, strict_op); + if (ipk1 < 0) + continue; + ipk2 = match_expr_to_partition_keys(expr2, rel2, strict_op); + if (ipk2 < 0) + continue; + + /* + * If the clause refers to keys at different ordinal positions, it can + * not be used for partitionwise join. + */ + if (ipk1 != ipk2) + continue; + + /* + * The clause allows partitionwise join only if it uses the same + * operator family as that specified by the partition key. + */ + if (rel1->part_scheme->strategy == PARTITION_STRATEGY_HASH) + { + if (!OidIsValid(rinfo->hashjoinoperator) || + !op_in_opfamily(rinfo->hashjoinoperator, + part_scheme->partopfamily[ipk1])) + continue; + } + else if (!list_member_oid(rinfo->mergeopfamilies, + part_scheme->partopfamily[ipk1])) + continue; + + /* Mark the partition key as having an equi-join clause. */ + pk_has_clause[ipk1] = true; + } + + /* Check whether every partition key has an equi-join condition. */ + for (cnt_pks = 0; cnt_pks < part_scheme->partnatts; cnt_pks++) + { + if (!pk_has_clause[cnt_pks]) + return false; + } + + return true; +} + +/* + * match_expr_to_partition_keys + * + * Tries to match an expression to one of the nullable or non-nullable + * partition keys of "rel". Returns the matched key's ordinal position, + * or -1 if the expression could not be matched to any of the keys. + * + * strict_op must be true if the expression will be compared with the + * partition key using a strict operator. This allows us to consider + * nullable as well as nonnullable partition keys. + */ +static int +match_expr_to_partition_keys(Expr *expr, RelOptInfo *rel, bool strict_op) +{ + int cnt; + + /* This function should be called only for partitioned relations. */ + Assert(rel->part_scheme); + Assert(rel->partexprs); + Assert(rel->nullable_partexprs); + + /* Remove any relabel decorations. */ + while (IsA(expr, RelabelType)) + expr = (Expr *) (castNode(RelabelType, expr))->arg; + + for (cnt = 0; cnt < rel->part_scheme->partnatts; cnt++) + { + ListCell *lc; + + /* We can always match to the non-nullable partition keys. */ + foreach(lc, rel->partexprs[cnt]) + { + if (equal(lfirst(lc), expr)) + return cnt; + } + + if (!strict_op) + continue; + + /* + * If it's a strict join operator then a NULL partition key on one + * side will not join to any partition key on the other side, and in + * particular such a row can't join to a row from a different + * partition on the other side. So, it's okay to search the nullable + * partition keys as well. + */ + foreach(lc, rel->nullable_partexprs[cnt]) + { + if (equal(lfirst(lc), expr)) + return cnt; + } + } + + return -1; +} + +/* + * set_joinrel_partition_key_exprs + * Initialize partition key expressions for a partitioned joinrel. + */ +static void +set_joinrel_partition_key_exprs(RelOptInfo *joinrel, + RelOptInfo *outer_rel, RelOptInfo *inner_rel, + JoinType jointype) +{ + int partnatts = joinrel->part_scheme->partnatts; + + joinrel->partexprs = (List **) palloc0(sizeof(List *) * partnatts); + joinrel->nullable_partexprs = + (List **) palloc0(sizeof(List *) * partnatts); + + /* + * The joinrel's partition expressions are the same as those of the input + * rels, but we must properly classify them as nullable or not in the + * joinrel's output. */ - for (cnt = 0; cnt < partnatts; cnt++) + for (int cnt = 0; cnt < partnatts; cnt++) { /* mark these const to enforce that we copy them properly */ const List *outer_expr = outer_rel->partexprs[cnt]; @@ -1738,18 +1913,41 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, switch (jointype) { + /* + * A join relation resulting from an INNER join may be + * regarded as partitioned by either of the inner and outer + * relation keys. For example, A INNER JOIN B ON A.a = B.b + * can be regarded as partitioned on either A.a or B.b. So we + * add both keys to the joinrel's partexpr lists. However, + * anything that was already nullable still has to be treated + * as nullable. + */ case JOIN_INNER: partexpr = list_concat_copy(outer_expr, inner_expr); nullable_partexpr = list_concat_copy(outer_null_expr, inner_null_expr); break; + /* + * A join relation resulting from a SEMI or ANTI join may be + * regarded as partitioned by the outer relation keys. The + * inner relation's keys are no longer interesting; since they + * aren't visible in the join output, nothing could join to + * them. + */ case JOIN_SEMI: case JOIN_ANTI: partexpr = list_copy(outer_expr); nullable_partexpr = list_copy(outer_null_expr); break; + /* + * A join relation resulting from a LEFT OUTER JOIN likewise + * may be regarded as partitioned on the (non-nullable) outer + * relation keys. The inner (nullable) relation keys are okay + * as partition keys for further joins as long as they involve + * strict join operators. + */ case JOIN_LEFT: partexpr = list_copy(outer_expr); nullable_partexpr = list_concat_copy(inner_expr, @@ -1758,6 +1956,12 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, inner_null_expr); break; + /* + * For FULL OUTER JOINs, both relations are nullable, so the + * resulting join relation may be regarded as partitioned on + * either of inner and outer relation keys, but only for joins + * that involve strict join operators. + */ case JOIN_FULL: nullable_partexpr = list_concat_copy(outer_expr, inner_expr); @@ -1769,7 +1973,6 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel, default: elog(ERROR, "unrecognized join type: %d", (int) jointype); - } joinrel->partexprs[cnt] = partexpr; |