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table.c
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table.c
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/*-------------------------------------------------------------------------
*
* table.c
* Commands for creating and altering distributed tables.
*
* Copyright (c) Citus Data, Inc.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "distributed/pg_version_constants.h"
#include "access/genam.h"
#include "access/htup_details.h"
#include "access/xact.h"
#include "catalog/index.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_class.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_type.h"
#include "commands/tablecmds.h"
#include "distributed/citus_ruleutils.h"
#include "distributed/colocation_utils.h"
#include "distributed/commands.h"
#include "distributed/commands/utility_hook.h"
#include "distributed/coordinator_protocol.h"
#include "distributed/deparser.h"
#include "distributed/deparse_shard_query.h"
#include "distributed/distribution_column.h"
#include "distributed/foreign_key_relationship.h"
#include "distributed/local_executor.h"
#include "distributed/listutils.h"
#include "distributed/metadata_sync.h"
#include "distributed/metadata/dependency.h"
#include "distributed/metadata/distobject.h"
#include "distributed/multi_executor.h"
#include "distributed/multi_partitioning_utils.h"
#include "distributed/reference_table_utils.h"
#include "distributed/relation_access_tracking.h"
#include "distributed/resource_lock.h"
#include "distributed/version_compat.h"
#include "distributed/worker_shard_visibility.h"
#include "distributed/tenant_schema_metadata.h"
#include "foreign/foreign.h"
#include "lib/stringinfo.h"
#include "nodes/parsenodes.h"
#include "parser/parse_expr.h"
#include "parser/parse_type.h"
#include "storage/lmgr.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
/* controlled via GUC, should be accessed via GetEnableLocalReferenceForeignKeys() */
bool EnableLocalReferenceForeignKeys = true;
/*
* GUC that controls whether to allow unique/exclude constraints without
* distribution column.
*/
bool AllowUnsafeConstraints = false;
/* Local functions forward declarations for unsupported command checks */
static void PostprocessCreateTableStmtForeignKeys(CreateStmt *createStatement);
static void PostprocessCreateTableStmtPartitionOf(CreateStmt *createStatement,
const char *queryString);
static void PreprocessAttachPartitionToCitusTable(Oid parentRelationId,
Oid partitionRelationId);
static void PreprocessAttachCitusPartitionToCitusTable(Oid parentCitusRelationId,
Oid partitionRelationId);
static void DistributePartitionUsingParent(Oid parentRelationId,
Oid partitionRelationId);
static void ErrorIfMultiLevelPartitioning(Oid parentRelationId, Oid partitionRelationId);
static void ErrorIfAttachCitusTableToPgLocalTable(Oid parentRelationId,
Oid partitionRelationId);
static bool DeparserSupportsAlterTableAddColumn(AlterTableStmt *alterTableStatement,
AlterTableCmd *addColumnSubCommand);
static bool ATDefinesFKeyBetweenPostgresAndCitusLocalOrRef(
AlterTableStmt *alterTableStatement);
static bool ShouldMarkConnectedRelationsNotAutoConverted(Oid leftRelationId,
Oid rightRelationId);
static bool RelationIdListContainsCitusTableType(List *relationIdList,
CitusTableType citusTableType);
static bool RelationIdListContainsPostgresTable(List *relationIdList);
static void ConvertPostgresLocalTablesToCitusLocalTables(
AlterTableStmt *alterTableStatement);
static bool RangeVarListHasLocalRelationConvertedByUser(List *relationRangeVarList,
AlterTableStmt *
alterTableStatement);
static int CompareRangeVarsByOid(const void *leftElement, const void *rightElement);
static List * GetAlterTableAddFKeyRightRelationIdList(
AlterTableStmt *alterTableStatement);
static List * GetAlterTableAddFKeyRightRelationRangeVarList(
AlterTableStmt *alterTableStatement);
static List * GetAlterTableAddFKeyConstraintList(AlterTableStmt *alterTableStatement);
static List * GetAlterTableCommandFKeyConstraintList(AlterTableCmd *command);
static List * GetRangeVarListFromFKeyConstraintList(List *fKeyConstraintList);
static List * GetRelationIdListFromRangeVarList(List *rangeVarList, LOCKMODE lockmode,
bool missingOk);
static bool AlterTableCommandTypeIsTrigger(AlterTableType alterTableType);
static bool AlterTableDropsForeignKey(AlterTableStmt *alterTableStatement);
static void ErrorIfUnsupportedAlterTableStmt(AlterTableStmt *alterTableStatement);
static bool AlterInvolvesPartitionColumn(AlterTableStmt *alterTableStatement,
AlterTableCmd *command);
static bool AlterColumnInvolvesIdentityColumn(AlterTableStmt *alterTableStatement,
AlterTableCmd *command);
static void ErrorIfUnsupportedAlterAddConstraintStmt(AlterTableStmt *alterTableStatement);
static List * CreateRightShardListForInterShardDDLTask(Oid rightRelationId,
Oid leftRelationId,
List *leftShardList);
static void SetInterShardDDLTaskPlacementList(Task *task,
ShardInterval *leftShardInterval,
ShardInterval *rightShardInterval);
static void SetInterShardDDLTaskRelationShardList(Task *task,
ShardInterval *leftShardInterval,
ShardInterval *rightShardInterval);
static Oid get_attrdef_oid(Oid relationId, AttrNumber attnum);
static char * GetAddColumnWithNextvalDefaultCmd(Oid sequenceOid, Oid relationId,
char *colname, TypeName *typeName,
bool ifNotExists);
static void ErrorIfAlterTableDropTableNameFromPostgresFdw(List *optionList, Oid
relationId);
/*
* We need to run some of the commands sequentially if there is a foreign constraint
* from/to reference table.
*/
static bool SetupExecutionModeForAlterTable(Oid relationId, AlterTableCmd *command);
/*
* PreprocessDropTableStmt processes DROP TABLE commands for partitioned tables.
* If we are trying to DROP partitioned tables, we first need to go to MX nodes
* and DETACH partitions from their parents. Otherwise, we process DROP command
* multiple times in MX workers. For shards, we send DROP commands with IF EXISTS
* parameter which solves problem of processing same command multiple times.
* However, for distributed table itself, we directly remove related table from
* Postgres catalogs via performDeletion function, thus we need to be cautious
* about not processing same DROP command twice.
*/
List *
PreprocessDropTableStmt(Node *node, const char *queryString,
ProcessUtilityContext processUtilityContext)
{
DropStmt *dropTableStatement = castNode(DropStmt, node);
Assert(dropTableStatement->removeType == OBJECT_TABLE);
List *tableNameList = NULL;
foreach_ptr(tableNameList, dropTableStatement->objects)
{
RangeVar *tableRangeVar = makeRangeVarFromNameList(tableNameList);
bool missingOK = true;
Oid relationId = RangeVarGetRelid(tableRangeVar, AccessShareLock, missingOK);
ErrorIfIllegallyChangingKnownShard(relationId);
/* we're not interested in non-valid, non-distributed relations */
if (relationId == InvalidOid || !IsCitusTable(relationId))
{
continue;
}
/*
* While changing the tables that are part of a colocation group we need to
* prevent concurrent mutations to the placements of the shard groups.
*/
CitusTableCacheEntry *cacheEntry = GetCitusTableCacheEntry(relationId);
if (cacheEntry->colocationId != INVALID_COLOCATION_ID)
{
LockColocationId(cacheEntry->colocationId, ShareLock);
}
/* invalidate foreign key cache if the table involved in any foreign key */
if ((TableReferenced(relationId) || TableReferencing(relationId)))
{
MarkInvalidateForeignKeyGraph();
}
/* we're only interested in partitioned and mx tables */
if (!ShouldSyncTableMetadata(relationId) || !PartitionedTable(relationId))
{
continue;
}
EnsureCoordinator();
List *partitionList = PartitionList(relationId);
if (list_length(partitionList) == 0)
{
continue;
}
SendCommandToWorkersWithMetadata(DISABLE_DDL_PROPAGATION);
Oid partitionRelationId = InvalidOid;
foreach_oid(partitionRelationId, partitionList)
{
char *detachPartitionCommand =
GenerateDetachPartitionCommand(partitionRelationId);
SendCommandToWorkersWithMetadata(detachPartitionCommand);
}
SendCommandToWorkersWithMetadata(ENABLE_DDL_PROPAGATION);
}
return NIL;
}
/*
* PostprocessCreateTableStmt takes CreateStmt object as a parameter and
* processes foreign keys on relation via PostprocessCreateTableStmtForeignKeys
* function.
*
* This function also processes CREATE TABLE ... PARTITION OF statements via
* PostprocessCreateTableStmtPartitionOf function.
*
* Also CREATE TABLE ... INHERITS ... commands are filtered here. If the inherited
* table is a distributed table, this function errors out, as we currently don't
* support local tables inheriting a distributed table.
*/
void
PostprocessCreateTableStmt(CreateStmt *createStatement, const char *queryString)
{
PostprocessCreateTableStmtForeignKeys(createStatement);
bool missingOk = false;
Oid relationId = RangeVarGetRelid(createStatement->relation, NoLock, missingOk);
Oid schemaId = get_rel_namespace(relationId);
if (createStatement->ofTypename && IsTenantSchema(schemaId))
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot create tables in a distributed schema using "
"CREATE TABLE OF syntax")));
}
if (createStatement->inhRelations != NIL)
{
if (createStatement->partbound != NULL)
{
/* process CREATE TABLE ... PARTITION OF command */
PostprocessCreateTableStmtPartitionOf(createStatement, queryString);
}
else
{
/* process CREATE TABLE ... INHERITS ... */
if (IsTenantSchema(schemaId))
{
ereport(ERROR, (errmsg("tables in a distributed schema cannot inherit "
"or be inherited")));
}
RangeVar *parentRelation = NULL;
foreach_ptr(parentRelation, createStatement->inhRelations)
{
Oid parentRelationId = RangeVarGetRelid(parentRelation, NoLock,
missingOk);
Assert(parentRelationId != InvalidOid);
/*
* Throw a better error message if the user tries to inherit a
* tenant table or if the user tries to inherit from a tenant
* table.
*/
if (IsTenantSchema(get_rel_namespace(parentRelationId)))
{
ereport(ERROR, (errmsg("tables in a distributed schema cannot "
"inherit or be inherited")));
}
else if (IsCitusTable(parentRelationId))
{
/* here we error out if inheriting a distributed table */
ereport(ERROR, (errmsg("non-distributed tables cannot inherit "
"distributed tables")));
}
}
}
}
}
/*
* PostprocessCreateTableStmtForeignKeys drops ands re-defines foreign keys
* defined by given CREATE TABLE command if command defined any foreign to
* reference or citus local tables.
*/
static void
PostprocessCreateTableStmtForeignKeys(CreateStmt *createStatement)
{
if (!ShouldEnableLocalReferenceForeignKeys())
{
/*
* Either the user disabled foreign keys from/to local/reference tables
* or the coordinator is not in the metadata */
return;
}
/*
* Relation must exist and it is already locked as standard process utility
* is already executed.
*/
bool missingOk = false;
Oid relationId = RangeVarGetRelid(createStatement->relation, NoLock, missingOk);
if (ShouldCreateTenantSchemaTable(relationId))
{
/*
* Avoid unnecessarily adding the table into metadata if we will
* distribute it as a tenant table later.
*/
return;
}
/*
* As we are just creating the table, we cannot have foreign keys that our
* relation is referenced. So we use INCLUDE_REFERENCING_CONSTRAINTS here.
* Reason behind using other two flags is explained below.
*/
int nonDistTableFKeysFlag = INCLUDE_REFERENCING_CONSTRAINTS |
INCLUDE_CITUS_LOCAL_TABLES |
INCLUDE_REFERENCE_TABLES;
List *nonDistTableForeignKeyIdList =
GetForeignKeyOids(relationId, nonDistTableFKeysFlag);
bool hasForeignKeyToNonDistTable = list_length(nonDistTableForeignKeyIdList) != 0;
if (hasForeignKeyToNonDistTable)
{
/*
* To support foreign keys from postgres tables to reference or citus
* local tables, we drop and re-define foreign keys so that our ALTER
* TABLE hook does the necessary job.
*/
List *relationFKeyCreationCommands =
GetForeignConstraintCommandsInternal(relationId, nonDistTableFKeysFlag);
DropRelationForeignKeys(relationId, nonDistTableFKeysFlag);
bool skip_validation = true;
ExecuteForeignKeyCreateCommandList(relationFKeyCreationCommands,
skip_validation);
}
}
/*
* ShouldEnableLocalReferenceForeignKeys is a wrapper around getting the GUC
* EnableLocalReferenceForeignKeys. If the coordinator is not added
* to the metadata, the function returns false. Else, the function returns
* the value set by the user
*
*/
bool
ShouldEnableLocalReferenceForeignKeys(void)
{
if (!EnableLocalReferenceForeignKeys)
{
return false;
}
return CoordinatorAddedAsWorkerNode();
}
/*
* PostprocessCreateTableStmtPartitionOf processes CREATE TABLE ... PARTITION OF
* statements and it checks if user creates the table as a partition of a distributed
* table. In that case, it distributes partition as well. Since the table itself is a
* partition, CreateDistributedTable will attach it to its parent table automatically
* after distributing it.
*/
static void
PostprocessCreateTableStmtPartitionOf(CreateStmt *createStatement, const
char *queryString)
{
RangeVar *parentRelation = linitial(createStatement->inhRelations);
bool missingOk = false;
Oid parentRelationId = RangeVarGetRelid(parentRelation, NoLock, missingOk);
/* a partition can only inherit from single parent table */
Assert(list_length(createStatement->inhRelations) == 1);
Assert(parentRelationId != InvalidOid);
Oid relationId = RangeVarGetRelid(createStatement->relation, NoLock, missingOk);
/*
* In case of an IF NOT EXISTS statement, Postgres lets it pass through the
* standardProcess_Utility, and gets into this Post-process hook by
* ignoring the statement if the table already exists. Thus, we need to make
* sure Citus behaves like plain PG in case the relation already exists.
*/
if (createStatement->if_not_exists)
{
if (IsCitusTable(relationId))
{
/*
* Ignore if the relation is already distributed.
*/
return;
}
else if (!PartitionTable(relationId) ||
PartitionParentOid(relationId) != parentRelationId)
{
/*
* Ignore if the relation is not a partition, or if that
* partition's parent is not the current parent from parentRelationId
*/
return;
}
}
if (IsTenantSchema(get_rel_namespace(parentRelationId)) ||
IsTenantSchema(get_rel_namespace(relationId)))
{
ErrorIfIllegalPartitioningInTenantSchema(parentRelationId, relationId);
}
/*
* If a partition is being created and if its parent is a distributed
* table, we will distribute this table as well.
*/
if (IsCitusTable(parentRelationId))
{
/*
* We can create Citus local tables right away, without switching to
* sequential mode, because they are going to have only one shard.
*/
if (IsCitusTableType(parentRelationId, CITUS_LOCAL_TABLE))
{
CreateCitusLocalTablePartitionOf(createStatement, relationId,
parentRelationId);
return;
}
DistributePartitionUsingParent(parentRelationId, relationId);
}
}
/*
* PreprocessAlterTableStmtAttachPartition takes AlterTableStmt object as
* parameter but it only processes into ALTER TABLE ... ATTACH PARTITION
* commands and distributes the partition if necessary. There are four cases
* to consider;
*
* Parent is not distributed, partition is not distributed: We do not need to
* do anything in this case.
*
* Parent is not distributed, partition is distributed: This can happen if
* user first distributes a table and tries to attach it to a non-distributed
* table. Non-distributed tables cannot have distributed partitions, thus we
* simply error out in this case.
*
* Parent is distributed, partition is not distributed: We should distribute
* the table and attach it to its parent in workers. CreateDistributedTable
* perform both of these operations. Thus, we will not propagate ALTER TABLE
* ... ATTACH PARTITION command to workers.
*
* Parent is distributed, partition is distributed: Partition is already
* distributed, we only need to attach it to its parent in workers. Attaching
* operation will be performed via propagating this ALTER TABLE ... ATTACH
* PARTITION command to workers.
*
* This function does nothing if the provided CreateStmt is not an ALTER TABLE ...
* ATTACH PARTITION OF command.
*/
List *
PreprocessAlterTableStmtAttachPartition(AlterTableStmt *alterTableStatement,
const char *queryString)
{
List *commandList = alterTableStatement->cmds;
AlterTableCmd *alterTableCommand = NULL;
foreach_ptr(alterTableCommand, commandList)
{
if (alterTableCommand->subtype == AT_AttachPartition)
{
/*
* We acquire the lock on the parent and child as we are in the pre-process
* and want to ensure we acquire the locks in the same order with Postgres
*/
LOCKMODE lockmode = AlterTableGetLockLevel(alterTableStatement->cmds);
Oid parentRelationId = AlterTableLookupRelation(alterTableStatement,
lockmode);
PartitionCmd *partitionCommand = (PartitionCmd *) alterTableCommand->def;
bool partitionMissingOk = true;
Oid partitionRelationId = RangeVarGetRelid(partitionCommand->name, lockmode,
partitionMissingOk);
if (!OidIsValid(partitionRelationId))
{
/*
* We can stop propagation here instead of logging error. Pg will complain
* in standard_utility, so we are safe to stop here. We pass missing_ok
* as true to not diverge from pg output.
*/
return NIL;
}
if (IsTenantSchema(get_rel_namespace(parentRelationId)) ||
IsTenantSchema(get_rel_namespace(partitionRelationId)))
{
ErrorIfIllegalPartitioningInTenantSchema(parentRelationId,
partitionRelationId);
}
if (!IsCitusTable(parentRelationId))
{
/*
* If the parent is a regular Postgres table, but the partition is a
* Citus table, we error out.
*/
ErrorIfAttachCitusTableToPgLocalTable(parentRelationId,
partitionRelationId);
/*
* If both the parent and the child table are Postgres tables,
* we can just skip preprocessing this command.
*/
continue;
}
/* Citus doesn't support multi-level partitioned tables */
ErrorIfMultiLevelPartitioning(parentRelationId, partitionRelationId);
/* attaching to a Citus table */
PreprocessAttachPartitionToCitusTable(parentRelationId, partitionRelationId);
}
}
return NIL;
}
/*
* PreprocessAttachPartitionToCitusTable takes a parent relation, which is a Citus table,
* and a partition to be attached to it.
* If the partition table is a regular Postgres table:
* - Converts the partition to Citus Local Table, if the parent is a Citus Local Table.
* - Distributes the partition, if the parent is a distributed table.
* If not, calls PreprocessAttachCitusPartitionToCitusTable to attach given partition to
* the parent relation.
*/
static void
PreprocessAttachPartitionToCitusTable(Oid parentRelationId, Oid partitionRelationId)
{
Assert(IsCitusTable(parentRelationId));
/* reference tables cannot be partitioned */
Assert(!IsCitusTableType(parentRelationId, REFERENCE_TABLE));
/* if parent of this table is distributed, distribute this table too */
if (!IsCitusTable(partitionRelationId))
{
if (IsCitusTableType(parentRelationId, CITUS_LOCAL_TABLE))
{
/*
* We pass the cascade option as false, since Citus Local Table partitions
* cannot have non-inherited foreign keys.
*/
bool cascadeViaForeignKeys = false;
CitusTableCacheEntry *entry = GetCitusTableCacheEntry(parentRelationId);
bool autoConverted = entry->autoConverted;
CreateCitusLocalTable(partitionRelationId, cascadeViaForeignKeys,
autoConverted);
}
else if (IsCitusTableType(parentRelationId, DISTRIBUTED_TABLE))
{
DistributePartitionUsingParent(parentRelationId, partitionRelationId);
}
}
else
{
/* both the parent and child are Citus tables */
PreprocessAttachCitusPartitionToCitusTable(parentRelationId, partitionRelationId);
}
}
/*
* PreprocessAttachCitusPartitionToCitusTable takes a parent relation, and a partition
* to be attached to it. Both of them are Citus tables.
* Errors out if the partition is a reference table.
* Errors out if the partition is distributed and the parent is a Citus Local Table.
* Distributes the partition, if it's a Citus Local Table, and the parent is distributed.
*/
static void
PreprocessAttachCitusPartitionToCitusTable(Oid parentCitusRelationId, Oid
partitionRelationId)
{
if (IsCitusTableType(partitionRelationId, REFERENCE_TABLE))
{
ereport(ERROR, (errmsg("partitioned reference tables are not supported")));
}
else if (IsCitusTableType(partitionRelationId, DISTRIBUTED_TABLE) &&
IsCitusTableType(parentCitusRelationId, CITUS_LOCAL_TABLE))
{
ereport(ERROR, (errmsg("non-distributed partitioned tables cannot have "
"distributed partitions")));
}
else if (IsCitusTableType(partitionRelationId, CITUS_LOCAL_TABLE) &&
IsCitusTableType(parentCitusRelationId, DISTRIBUTED_TABLE))
{
/* if the parent is a distributed table, distribute the partition too */
DistributePartitionUsingParent(parentCitusRelationId, partitionRelationId);
}
else if (IsCitusTableType(partitionRelationId, CITUS_LOCAL_TABLE) &&
IsCitusTableType(parentCitusRelationId, CITUS_LOCAL_TABLE))
{
/*
* We should ensure that the partition relation has no foreign keys,
* as Citus Local Table partitions can only have inherited foreign keys.
*/
if (TableHasExternalForeignKeys(partitionRelationId))
{
ereport(ERROR, (errmsg("partition local tables added to citus metadata "
"cannot have non-inherited foreign keys")));
}
}
/*
* We don't need to add other cases here, like distributed - distributed and
* citus_local - citus_local, as PreprocessAlterTableStmt and standard process
* utility would do the work to attach partitions to shell and shard relations.
*/
}
/*
* DistributePartitionUsingParent takes a parent and a partition relation and
* distributes the partition, using the same distribution column as the parent, if the
* parent has a distribution column. It creates a *hash* distributed table by default, as
* partitioned tables can only be distributed by hash, unless it's null key distributed.
*
* If the parent has no distribution key, we distribute the partition with null key too.
*/
static void
DistributePartitionUsingParent(Oid parentCitusRelationId, Oid partitionRelationId)
{
char *parentRelationName = generate_qualified_relation_name(parentCitusRelationId);
/*
* We can create tenant tables and single shard tables right away, without
* switching to sequential mode, because they are going to have only one shard.
*/
if (ShouldCreateTenantSchemaTable(partitionRelationId))
{
CreateTenantSchemaTable(partitionRelationId);
return;
}
else if (!HasDistributionKey(parentCitusRelationId))
{
/*
* If the parent is null key distributed, we should distribute the partition
* with null distribution key as well.
*/
ColocationParam colocationParam = {
.colocationParamType = COLOCATE_WITH_TABLE_LIKE_OPT,
.colocateWithTableName = parentRelationName,
};
CreateSingleShardTable(partitionRelationId, colocationParam);
return;
}
Var *distributionColumn = DistPartitionKeyOrError(parentCitusRelationId);
char *distributionColumnName = ColumnToColumnName(parentCitusRelationId,
(Node *) distributionColumn);
char distributionMethod = DISTRIBUTE_BY_HASH;
SwitchToSequentialAndLocalExecutionIfPartitionNameTooLong(
parentCitusRelationId, partitionRelationId);
CreateDistributedTable(partitionRelationId, distributionColumnName,
distributionMethod, ShardCount, false,
parentRelationName);
}
/*
* ErrorIfMultiLevelPartitioning takes a parent, and a partition relation to be attached
* and errors out if the partition is also a partitioned table, which means we are
* trying to build a multi-level partitioned table.
*/
static void
ErrorIfMultiLevelPartitioning(Oid parentRelationId, Oid partitionRelationId)
{
if (PartitionedTable(partitionRelationId))
{
char *relationName = get_rel_name(partitionRelationId);
char *parentRelationName = get_rel_name(parentRelationId);
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Citus doesn't support multi-level "
"partitioned tables"),
errdetail("Relation \"%s\" is partitioned table "
"itself and it is also partition of "
"relation \"%s\".",
relationName, parentRelationName)));
}
}
/*
* ErrorIfAttachCitusTableToPgLocalTable takes a parent, and a partition relation
* to be attached. Errors out if the partition is a Citus table, and the parent is a
* regular Postgres table.
*/
static void
ErrorIfAttachCitusTableToPgLocalTable(Oid parentRelationId, Oid partitionRelationId)
{
if (!IsCitusTable(parentRelationId) &&
IsCitusTable(partitionRelationId))
{
char *parentRelationName = get_rel_name(parentRelationId);
ereport(ERROR, (errmsg("non-citus partitioned tables cannot have "
"citus table partitions"),
errhint("Distribute the partitioned table \"%s\" "
"instead, or add it to metadata", parentRelationName)));
}
}
/*
* PostprocessAlterTableSchemaStmt is executed after the change has been applied
* locally, we can now use the new dependencies of the table to ensure all its
* dependencies exist on the workers before we apply the commands remotely.
*/
List *
PostprocessAlterTableSchemaStmt(Node *node, const char *queryString)
{
AlterObjectSchemaStmt *stmt = castNode(AlterObjectSchemaStmt, node);
Assert(stmt->objectType == OBJECT_TABLE || stmt->objectType == OBJECT_FOREIGN_TABLE);
/*
* We will let Postgres deal with missing_ok
*/
List *tableAddresses = GetObjectAddressListFromParseTree((Node *) stmt, true, true);
/* the code-path only supports a single object */
Assert(list_length(tableAddresses) == 1);
/* We have already asserted that we have exactly 1 address in the addresses. */
ObjectAddress *tableAddress = linitial(tableAddresses);
/*
* Check whether we are dealing with a sequence or view here and route queries
* accordingly to the right processor function.
*/
char relKind = get_rel_relkind(tableAddress->objectId);
if (relKind == RELKIND_SEQUENCE)
{
stmt->objectType = OBJECT_SEQUENCE;
return PostprocessAlterSequenceSchemaStmt((Node *) stmt, queryString);
}
else if (relKind == RELKIND_VIEW)
{
stmt->objectType = OBJECT_VIEW;
return PostprocessAlterViewSchemaStmt((Node *) stmt, queryString);
}
if (!ShouldPropagate() || !IsCitusTable(tableAddress->objectId))
{
return NIL;
}
EnsureAllObjectDependenciesExistOnAllNodes(tableAddresses);
return NIL;
}
/*
* ChooseForeignKeyConstraintNameAddition returns the string of column names to be used when generating a foreign
* key constraint name. This function is copied from postgres codebase.
*/
static char *
ChooseForeignKeyConstraintNameAddition(List *columnNames)
{
char buf[NAMEDATALEN * 2];
int buflen = 0;
buf[0] = '\0';
String *columnNameString = NULL;
foreach_ptr(columnNameString, columnNames)
{
const char *name = strVal(columnNameString);
if (buflen > 0)
{
buf[buflen++] = '_'; /* insert _ between names */
}
/*
* At this point we have buflen <= NAMEDATALEN. name should be less
* than NAMEDATALEN already, but use strlcpy for paranoia.
*/
strlcpy(buf + buflen, name, NAMEDATALEN);
buflen += strlen(buf + buflen);
if (buflen >= NAMEDATALEN)
{
break;
}
}
return pstrdup(buf);
}
/*
* GenerateConstraintName creates and returns a default name for the constraints Citus supports
* for default naming. See ConstTypeCitusCanDefaultName function for the supported constraint types.
*/
static char *
GenerateConstraintName(const char *tableName, Oid namespaceId, Constraint *constraint)
{
char *conname = NULL;
switch (constraint->contype)
{
case CONSTR_PRIMARY:
{
conname = ChooseIndexName(tableName, namespaceId,
NULL, NULL, true, true);
break;
}
case CONSTR_UNIQUE:
{
ListCell *lc;
List *indexParams = NIL;
foreach(lc, constraint->keys)
{
IndexElem *iparam = makeNode(IndexElem);
iparam->name = pstrdup(strVal(lfirst(lc)));
indexParams = lappend(indexParams, iparam);
}
conname = ChooseIndexName(tableName, namespaceId,
ChooseIndexColumnNames(indexParams),
NULL, false, true);
break;
}
case CONSTR_EXCLUSION:
{
ListCell *lc;
List *indexParams = NIL;
List *excludeOpNames = NIL;
foreach(lc, constraint->exclusions)
{
List *pair = (List *) lfirst(lc);
Assert(list_length(pair) == 2);
IndexElem *elem = linitial_node(IndexElem, pair);
List *opname = lsecond_node(List, pair);
indexParams = lappend(indexParams, elem);
excludeOpNames = lappend(excludeOpNames, opname);
}
conname = ChooseIndexName(tableName, namespaceId,
ChooseIndexColumnNames(indexParams),
excludeOpNames,
false, true);
break;
}
case CONSTR_CHECK:
{
conname = ChooseConstraintName(tableName, NULL, "check", namespaceId, NIL);
break;
}
case CONSTR_FOREIGN:
{
conname = ChooseConstraintName(tableName,
ChooseForeignKeyConstraintNameAddition(
constraint->fk_attrs),
"fkey",
namespaceId,
NIL);
break;
}
default:
{
ereport(ERROR, (errmsg(
"unsupported constraint type for generating a constraint name: %d",
constraint->contype)));
break;
}
}
return conname;
}
/*
* EnsureSequentialModeForAlterTableOperation makes sure that the current transaction is already in
* sequential mode, or can still safely be put in sequential mode, it errors if that is
* not possible. The error contains information for the user to retry the transaction with
* sequential mode set from the beginning.
*/
static void
EnsureSequentialModeForAlterTableOperation(void)
{
const char *objTypeString = "ALTER TABLE ... ADD FOREIGN KEY";
if (ParallelQueryExecutedInTransaction())
{
ereport(ERROR, (errmsg("cannot run %s command because there was a "
"parallel operation on a distributed table in the "
"transaction", objTypeString),
errdetail("When running command on/for a distributed %s, Citus "
"needs to perform all operations over a single "
"connection per node to ensure consistency.",
objTypeString),
errhint("Try re-running the transaction with "
"\"SET LOCAL citus.multi_shard_modify_mode TO "
"\'sequential\';\"")));
}
ereport(DEBUG1, (errmsg("switching to sequential query execution mode"),
errdetail(
"A command for a distributed %s is run. To make sure subsequent "
"commands see the %s correctly we need to make sure to "
"use only one connection for all future commands",
objTypeString, objTypeString)));
SetLocalMultiShardModifyModeToSequential();
}
/*
* SwitchToSequentialAndLocalExecutionIfConstraintNameTooLong generates the longest index constraint name
* among the shards of the partitions, and if exceeds the limit switches to sequential and
* local execution to prevent self-deadlocks.
*/
static void
SwitchToSequentialAndLocalExecutionIfConstraintNameTooLong(Oid relationId,
Constraint *constraint)
{
if (!PartitionedTable(relationId))
{
/* Citus already handles long names for regular tables */
return;
}
if (ShardIntervalCount(relationId) == 0)
{
/*
* Relation has no shards, so we cannot run into "long shard index
* name" issue.
*/
return;
}
Oid longestNamePartitionId = PartitionWithLongestNameRelationId(relationId);
if (!OidIsValid(longestNamePartitionId))
{
/* no partitions have been created yet */
return;
}
char *longestPartitionShardName = get_rel_name(longestNamePartitionId);
ShardInterval *shardInterval = LoadShardIntervalWithLongestShardName(
longestNamePartitionId);
AppendShardIdToName(&longestPartitionShardName, shardInterval->shardId);
Relation rel = RelationIdGetRelation(longestNamePartitionId);
Oid namespaceOid = RelationGetNamespace(rel);
RelationClose(rel);
char *longestConname = GenerateConstraintName(longestPartitionShardName,
namespaceOid, constraint);
if (longestConname && strnlen(longestConname, NAMEDATALEN) >= NAMEDATALEN - 1)
{
if (ParallelQueryExecutedInTransaction())
{
/*
* If there has already been a parallel query executed, the sequential mode
* would still use the already opened parallel connections to the workers,
* thus contradicting our purpose of using sequential mode.
*/
ereport(ERROR, (errmsg(
"The constraint name (%s) on a shard is too long and could lead "