mirror of https://github.com/citusdata/citus.git
implement DROP CONSTRAINT fkey between local tables & reference tables
Onur Tirtir
parent
a40d36b783
commit
ef1447e360
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@ -17,6 +17,7 @@
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#include "access/xact.h"
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#include "catalog/index.h"
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#include "catalog/pg_class.h"
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#include "catalog/pg_constraint.h"
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#include "commands/tablecmds.h"
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#include "distributed/citus_ruleutils.h"
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#include "distributed/colocation_utils.h"
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@ -37,6 +38,7 @@
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#include "nodes/parsenodes.h"
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#include "storage/lmgr.h"
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#include "utils/builtins.h"
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#include "utils/fmgroids.h"
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#include "utils/lsyscache.h"
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#include "utils/syscache.h"
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@ -567,86 +569,248 @@ PreprocessAlterTableAddDropFKey(AlterTableStmt *alterTableStatement)
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{
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AlterTableType alterTableType = command->subtype;
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if (alterTableType != AT_AddConstraint)
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if (alterTableType == AT_AddConstraint)
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{
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continue;
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}
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Constraint *constraint = (Constraint *) command->def;
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/* found an ADD CONSTRAINT subcommand */
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if (constraint->contype != CONSTR_FOREIGN)
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{
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continue;
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}
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Constraint *constraint = (Constraint *) command->def;
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/* found an ADD CONSTRAINT (foreign key) subcommand */
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if (constraint->contype != CONSTR_FOREIGN)
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{
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continue;
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}
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/* TODO: should I take lock here */
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Oid referencedRelationOid = RangeVarGetRelid(constraint->pktable, NoLock,
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alterTableStatement->missing_ok);
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/* found an ADD CONSTRAINT (foreign key) subcommand */
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if (!OidIsValid(referencedRelationOid))
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{
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continue;
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}
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/* check for skip_validation field */
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if (!referencingIsLocalTable)
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{
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/*
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* Foreign constraint validations will be done in workers if referencing
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* table is not a distributed table.
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* If we do not set this flag, PostgreSQL tries to do additional checking when we drop
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* to standard_ProcessUtility. standard_ProcessUtility tries to open new
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* connections to workers to verify foreign constraints while original
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* transaction is in process, which causes deadlock.
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*
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* Note that if referencing table is a local table, we should perform needed
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* checks in coordinator as the command will be executed only in the coordinator.
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*/
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constraint->skip_validation = true;
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}
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/* TODO: should I take lock here */
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Oid referencedRelationOid = RangeVarGetRelid(constraint->pktable, NoLock,
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alterTableStatement->missing_ok);
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if (!OidIsValid(referencedRelationOid))
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{
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continue;
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}
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bool referencedIsLocalTable = !IsDistributedTable(referencedRelationOid);
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bool referencedIsReferenceTable = !referencedIsLocalTable &&
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(PartitionMethod(referencedRelationOid) ==
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DISTRIBUTE_BY_NONE);
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bool referencedIsLocalTable = !IsCitusTable(referencedRelationOid);
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bool referencedIsReferenceTable = !referencedIsLocalTable &&
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(PartitionMethod(referencedRelationOid) ==
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DISTRIBUTE_BY_NONE);
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ErrorIfUnsupportedAlterAddDropFKeyBetweenReferecenceAndLocalTable(
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referencingRelationOid,
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referencedRelationOid,
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referencingRelationOid,
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referencedRelationOid,
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AT_AddConstraint,
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constraint);
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constraint);
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/*
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* Replace reference table's name if we are to define foreign key constraint
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* between a local table and a reference table
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*/
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/*
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* Replace reference table's name if we are to define foreign key constraint
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* between a local table and a reference table
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*/
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/* reference table references to a local table */
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if (referencingIsReferenceTable && referencedIsLocalTable)
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{
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/* rewrite referencing table name */
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Oid referenceTableShardOid = GetOnlyShardOidOfReferenceTable(
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referencingRelationOid);
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if (referencingIsReferenceTable && referencedIsLocalTable)
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{
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/* reference table references to a local table, rewrite referencing table name */
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Oid referenceTableShardOid = GetOnlyShardOidOfReferenceTable(
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referencingRelationOid);
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alterTableStatement->relation->relname = get_rel_name(
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referenceTableShardOid);
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}
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else if (referencingIsLocalTable && referencedIsReferenceTable)
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{
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/* local table references to a reference table, rewrite referenced table name */
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Oid referenceTableShardOid = GetOnlyShardOidOfReferenceTable(
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referencedRelationOid);
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constraint->pktable->relname = get_rel_name(referenceTableShardOid);
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}
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/* check for skip_validation field */
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bool fKeyFromReferenceTableToLocalTable = referencingIsReferenceTable &&
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referencedIsLocalTable;
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if (!referencingIsLocalTable && !fKeyFromReferenceTableToLocalTable)
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{
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/*
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* Foreign constraint validations will be done in workers if referencing
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* table is not a distributed table or we are defining a foreign key constraint
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* from a reference table to a coordinator local table.
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* If we do not set this flag, PostgreSQL tries to do additional checking when
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* we drop to standard_ProcessUtility. standard_ProcessUtility tries to open new
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* connections to workers to verify foreign constraints while original transaction
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* is in process, which causes deadlock.
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*/
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constraint->skip_validation = true;
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}
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}
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/* local table references to a reference table */
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else if (referencingIsLocalTable && referencedIsReferenceTable)
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else if (alterTableType == AT_DropConstraint)
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{
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/* rewrite referenced table name */
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Oid referenceTableShardOid = GetOnlyShardOidOfReferenceTable(
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referencedRelationOid);
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constraint->pktable->relname = get_rel_name(referenceTableShardOid);
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if (referencingIsReferenceTable)
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{
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/*
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* Find referenced table OID by traversing the constraints defined for
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* reference table's only shard. If referenced table is local table,
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* then replace reference table's name and perform checks via
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* ErrorIfUnsupportedAlterAddDropFKeyBetweenReferecenceAndLocalTable
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*/
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Oid referenceTableShardOid = GetOnlyShardOidOfReferenceTable(
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referencingRelationOid);
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const char *constraintName = command->name;
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Oid referencedRelationOid = GetReferencedTableOidByFKeyConstraintName(
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referenceTableShardOid, constraintName);
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if (!OidIsValid(referencedRelationOid) || IsCitusTable(
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referencedRelationOid))
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{
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/*
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* Constraint with constraintName does not belong to a fkey constraint of
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* referencing relation or the referencing relation is not a local table.
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* Do not replace reference table's name and do not perform checks
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* via ErrorIfUnsupportedAlterAddDropFKeyBetweenReferecenceAndLocalTable,
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* PostgreSQL will already error out
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*/
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continue;
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}
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/*
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* Now we have a foreign key constraint to be dropped via and ALTER TABLE DROP
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* CONSTRAINT command, which is previously defined from a reference table to
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* a coordinator local table
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*/
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/* we pass constraint to be NULL to perform ALTER TABLE DROP constraint checks */
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Constraint *constraint = NULL;
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ErrorIfUnsupportedAlterAddDropFKeyBetweenReferecenceAndLocalTable(
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referencingRelationOid,
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referencedRelationOid,
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AT_DropConstraint,
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constraint);
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/* rewrite referenced table name */
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alterTableStatement->relation->relname = get_rel_name(
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referenceTableShardOid);
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}
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else if (referencingIsLocalTable)
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{
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/*
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* Find referenced table OID by traversing the constraints defined for
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* local table. If referenced table is the only shard of a reference
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* table, find the reference table owning that shard and perform checks
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* via
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* ErrorIfUnsupportedAlterAddDropFKeyBetweenReferecenceAndLocalTable
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*/
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const char *constraintName = command->name;
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Oid referencedRelationOid = GetReferencedTableOidByFKeyConstraintName(
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referencingRelationOid, constraintName);
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/* search owner relation only in current search path */
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bool onlySearchPath = true;
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Oid candidateReferenceTableOid = GetOwnerRelationOid(
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referencedRelationOid, onlySearchPath);
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bool candidateIsReferenceTable = OidIsValid(candidateReferenceTableOid) &&
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(PartitionMethod(
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candidateReferenceTableOid) ==
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DISTRIBUTE_BY_NONE);
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if (!candidateIsReferenceTable)
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{
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/*
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* Constraint with constraintName does not belong to a foreign key constraint
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* of referencing relation or the referencing relation is not a reference table
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* shard. Do do not perform checks
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* via ErrorIfUnsupportedAlterAddDropFKeyBetweenReferecenceAndLocalTable,
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* PostgreSQL will already error out.
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*/
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continue;
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}
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/*
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* Now we have a foreign key constraint to be droped via and ALTER TABLE DROP
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* CONSTRAINT command, which is previously defined from a coordinator local
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* table to a reference reference table, whose relation id is
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* candidateReferenceTableOid
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*/
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/* we pass constraint to be NULL to perform ALTER TABLE DROP constraint checks */
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Constraint *constraint = NULL;
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/* perform checks using the reference table itself */
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ErrorIfUnsupportedAlterAddDropFKeyBetweenReferecenceAndLocalTable(
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referencingRelationOid,
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candidateReferenceTableOid,
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AT_DropConstraint,
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constraint);
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}
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}
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}
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}
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/*
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* GetReferencedTableOidByFKeyConstraintName returns OID of the referenced table
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* that is referenced by table with referencingRelationOid in terms of foreign
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* key constraint with constraintName. It does that by scanning pg_constraint
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* for foreign key constraints.
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*
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* If there does not exist such a foreign key constraint, returns InvalidOid
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*/
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static Oid
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GetReferencedTableOidByFKeyConstraintName(Oid referencingRelationOid, const
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char *constraintName)
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{
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Oid referencedTableOid = InvalidOid;
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ScanKeyData scanKey[1];
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int scanKeyCount = 1;
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Relation pgConstraint = heap_open(ConstraintRelationId, AccessShareLock);
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ScanKeyInit(&scanKey[0], Anum_pg_constraint_conrelid, BTEqualStrategyNumber, F_OIDEQ,
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referencingRelationOid);
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SysScanDesc scanDescriptor = systable_beginscan(pgConstraint,
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ConstraintRelidTypidNameIndexId,
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true, NULL,
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scanKeyCount, scanKey);
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HeapTuple heapTuple = systable_getnext(scanDescriptor);
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while (HeapTupleIsValid(heapTuple))
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{
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Form_pg_constraint constraintForm = (Form_pg_constraint) GETSTRUCT(heapTuple);
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const char *foundConstraintName = constraintForm->conname.data;
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char foundConstraintType = constraintForm->contype;
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if (foundConstraintType == CONSTRAINT_FOREIGN && strncasecmp(foundConstraintName,
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constraintName,
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NAMEDATALEN) == 0)
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{
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/*
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* Found the foreign key constraint with name "constraintName",
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* set referenced table's OID
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*/
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referencedTableOid = constraintForm->confrelid;
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break;
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}
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heapTuple = systable_getnext(scanDescriptor);
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}
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/* clean up scan and close system catalog */
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systable_endscan(scanDescriptor);
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heap_close(pgConstraint, AccessShareLock);
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return referencedTableOid;
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}
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/*
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* PreprocessAlterTableStmt issues a warning.
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* ALTER TABLE ALL IN TABLESPACE statements have their node type as
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