diff options
| -rw-r--r-- | src/backend/optimizer/util/pgxcship.c | 56 | ||||
| -rw-r--r-- | src/test/regress/expected/xc_constraints.out | 3 | ||||
| -rw-r--r-- | src/test/regress/sql/xc_constraints.sql | 2 |
3 files changed, 26 insertions, 35 deletions
diff --git a/src/backend/optimizer/util/pgxcship.c b/src/backend/optimizer/util/pgxcship.c index 2b5b6966c6..ec8a1ab939 100644 --- a/src/backend/optimizer/util/pgxcship.c +++ b/src/backend/optimizer/util/pgxcship.c @@ -1574,6 +1574,13 @@ pgxc_check_index_shippability(RelationLocInfo *relLocInfo, } /* + * 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->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 @@ -1619,13 +1626,9 @@ pgxc_check_index_shippability(RelationLocInfo *relLocInfo, case LOCATOR_TYPE_HASH: case LOCATOR_TYPE_MODULO: /* - * Index on Hash and Modulo tables are shippable if the index - * columns include the list of all column keys of distribution. - * We need also to check if this index uses expressions. Such - * expressions are not shippable if they do not satisfy the - * following conditions: - * - expression uses non-distribution columns - * - expression uses more than 1 distribution column + * 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: @@ -1637,40 +1640,27 @@ pgxc_check_index_shippability(RelationLocInfo *relLocInfo, * 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 - * use as Var only distributed colums as the hash output of + * 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. + * 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 - * once such a feature is implemented. + * onde a relation distribution will be able to be defined based + * on an expression of multiple columns. */ - /* Evaluate expression shippability based on index uniqueness */ + /* Index contains expressions, it cannot be shipped safely */ if (indexExprs != NIL) { - /* - * Check if the expressions use only distribution columns. - * In order to evaluate that get all the variable expressions. - */ - List *indexVars = pull_var_clause((Node *) indexExprs, - PVC_RECURSE_AGGREGATES, - PVC_RECURSE_PLACEHOLDERS); - foreach(lc, indexVars) - { - Var *var = (Var *) lfirst(lc); - - /* - * Check if attribute is the distribution column. - * PGXCTODO: this will need modifications once - * multi-column distribution is implemented. - */ - if (var->varattno != relLocInfo->partAttrNum) - { - result = false; - break; - } - } + result = false; + break; } /* Nothing to do if no attributes */ diff --git a/src/test/regress/expected/xc_constraints.out b/src/test/regress/expected/xc_constraints.out index 7351de5381..75d891ce48 100644 --- a/src/test/regress/expected/xc_constraints.out +++ b/src/test/regress/expected/xc_constraints.out @@ -24,8 +24,9 @@ ERROR: Cannot create index whose evaluation cannot be enforced to remote nodes CREATE UNIQUE INDEX xc_cons_hash_unique1 ON xc_cons_hash(c1); -- OK, contains distribution column CREATE UNIQUE INDEX xc_cons_hash_unique2 ON xc_cons_hash(c1,c2); --- OK, expression contains only distribution column +-- error, expression contains only distribution column CREATE UNIQUE INDEX xc_cons_hash_unique3 ON xc_cons_hash((c1 || c1)); +ERROR: Cannot create index whose evaluation cannot be enforced to remote nodes -- error, expression contains other columns than distribution one CREATE UNIQUE INDEX xc_cons_hash_unique3 ON xc_cons_hash((c1 || c2)); ERROR: Cannot create index whose evaluation cannot be enforced to remote nodes diff --git a/src/test/regress/sql/xc_constraints.sql b/src/test/regress/sql/xc_constraints.sql index 8c98b2e13b..96318a1377 100644 --- a/src/test/regress/sql/xc_constraints.sql +++ b/src/test/regress/sql/xc_constraints.sql @@ -24,7 +24,7 @@ CREATE UNIQUE INDEX xc_cons_rr_unique3 ON xc_cons_rr((c2 || c3)); -- error, not CREATE UNIQUE INDEX xc_cons_hash_unique1 ON xc_cons_hash(c1); -- OK, contains distribution column CREATE UNIQUE INDEX xc_cons_hash_unique2 ON xc_cons_hash(c1,c2); --- OK, expression contains only distribution column +-- error, expression contains only distribution column CREATE UNIQUE INDEX xc_cons_hash_unique3 ON xc_cons_hash((c1 || c1)); -- error, expression contains other columns than distribution one CREATE UNIQUE INDEX xc_cons_hash_unique3 ON xc_cons_hash((c1 || c2)); |