/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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#include "postgres.h"
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#include "catalog/dependency.h"
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#include "catalog/objectaccess.h"
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#include "catalog/pg_class_d.h"
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#include "catalog/pg_namespace_d.h"
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#include "commands/defrem.h"
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#include "tcop/utility.h"
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#include "utils/lsyscache.h"
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#include "catalog/ag_catalog.h"
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#include "catalog/ag_graph.h"
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#include "catalog/ag_label.h"
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#include "catalog/ag_namespace.h"
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#include "utils/ag_cache.h"
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static object_access_hook_type prev_object_access_hook;
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static ProcessUtility_hook_type prev_process_utility_hook;
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static bool prev_object_hook_is_set;
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static void object_access(ObjectAccessType access, Oid class_id, Oid object_id,
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int sub_id, void *arg);
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void ag_ProcessUtility_hook(PlannedStmt *pstmt, const char *queryString, bool readOnlyTree,
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ProcessUtilityContext context, ParamListInfo params,
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QueryEnvironment *queryEnv, DestReceiver *dest,
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QueryCompletion *qc);
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static bool is_age_drop(PlannedStmt *pstmt);
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static void drop_age_extension(DropStmt *stmt);
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void object_access_hook_init(void)
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{
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prev_object_access_hook = object_access_hook;
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object_access_hook = object_access;
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prev_object_hook_is_set = true;
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}
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void object_access_hook_fini(void)
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{
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if (prev_object_hook_is_set)
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{
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object_access_hook = prev_object_access_hook;
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prev_object_access_hook = NULL;
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prev_object_hook_is_set = false;
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}
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}
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void process_utility_hook_init(void)
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{
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prev_process_utility_hook = ProcessUtility_hook;
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ProcessUtility_hook = ag_ProcessUtility_hook;
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}
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void process_utility_hook_fini(void)
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{
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ProcessUtility_hook = prev_process_utility_hook;
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}
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/*
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* When Postgres tries to drop AGE using the standard logic, two issues occur:
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*
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* 1. The schema that graphs in stored in are not dropped.
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*
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* 2. While dropping ag_catalog, the object hook is run. Which uses the
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* information in the indexes and tables being dropped. To prevent an error
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* from being thrown, we need to disable the object_access_hook before dropping
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* the extension.
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*/
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void ag_ProcessUtility_hook(PlannedStmt *pstmt, const char *queryString, bool readOnlyTree,
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ProcessUtilityContext context, ParamListInfo params,
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QueryEnvironment *queryEnv, DestReceiver *dest,
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QueryCompletion *qc)
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{
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if (is_age_drop(pstmt))
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drop_age_extension((DropStmt *)pstmt->utilityStmt);
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else if (prev_process_utility_hook)
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(*prev_process_utility_hook) (pstmt, queryString, readOnlyTree, context, params,
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queryEnv, dest, qc);
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else
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standard_ProcessUtility(pstmt, queryString, readOnlyTree, context, params, queryEnv,
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dest, qc);
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}
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static void drop_age_extension(DropStmt *stmt)
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{
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// Remove all graphs
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drop_graphs(get_graphnames());
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// Remove the object access hook
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object_access_hook_fini();
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/*
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* Run Postgres' logic to perform the remaining work to drop the
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* extension.
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*/
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RemoveObjects(stmt);
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/* reset global variables for OIDs */
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clear_global_Oids_AGTYPE();
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clear_global_Oids_GRAPHID();
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}
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// Check to see if the Utility Command is to drop the AGE Extension.
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static bool is_age_drop(PlannedStmt *pstmt)
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{
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ListCell *lc;
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DropStmt *drop_stmt;
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if (!IsA(pstmt->utilityStmt, DropStmt))
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return false;
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drop_stmt = (DropStmt *)pstmt->utilityStmt;
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foreach(lc, drop_stmt->objects)
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{
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Node *obj = lfirst(lc);
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if (IsA(obj, String))
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{
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Value *val = (Value *)obj;
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char *str = val->val.str;
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if (!pg_strcasecmp(str, "age"))
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return true;
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}
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}
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return false;
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}
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/*
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* object_access_hook is called before actual deletion. So, looking up ag_cache
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* is still valid at this point. For labels, once a backed table is deleted,
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* its corresponding ag_label cache entry will be removed by cache
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* invalidation.
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*/
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static void object_access(ObjectAccessType access, Oid class_id, Oid object_id,
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int sub_id, void *arg)
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{
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ObjectAccessDrop *drop_arg;
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if (prev_object_access_hook)
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prev_object_access_hook(access, class_id, object_id, sub_id, arg);
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// We are interested in DROP SCHEMA and DROP TABLE commands.
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if (access != OAT_DROP)
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return;
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drop_arg = arg;
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/*
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* PERFORM_DELETION_INTERNAL flag will be set when remove_schema() calls
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* performDeletion(). However, if PostgreSQL does performDeletion() with
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* PERFORM_DELETION_INTERNAL flag over backed schemas of graphs due to
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* side effects of other commands run by user, it is impossible to
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* distinguish between this and drop_graph().
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*
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* The above applies to DROP TABLE command too.
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*/
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if (class_id == NamespaceRelationId)
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{
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graph_cache_data *cache_data;
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if (drop_arg->dropflags & PERFORM_DELETION_INTERNAL)
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return;
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cache_data = search_graph_namespace_cache(object_id);
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if (cache_data)
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{
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char *nspname = get_namespace_name(object_id);
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ereport(ERROR, (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
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errmsg("schema \"%s\" is for graph \"%s\"",
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nspname, NameStr(cache_data->name))));
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}
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return;
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}
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if (class_id == RelationRelationId)
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{
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label_cache_data *cache_data;
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cache_data = search_label_relation_cache(object_id);
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// We are interested in only tables that are labels.
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if (!cache_data)
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return;
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if (drop_arg->dropflags & PERFORM_DELETION_INTERNAL)
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{
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/*
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* Remove the corresponding ag_label entry here first. We don't
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* know whether this operation is drop_label() or a part of
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* drop_graph().
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*/
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delete_label(object_id);
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}
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else
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{
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char *relname = get_rel_name(object_id);
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ereport(ERROR, (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
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errmsg("table \"%s\" is for label \"%s\"",
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relname, NameStr(cache_data->name))));
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}
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}
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}
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Oid ag_relation_id(const char *name, const char *kind)
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{
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Oid id;
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id = get_relname_relid(name, ag_catalog_namespace_id());
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if (!OidIsValid(id))
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{
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ereport(ERROR, (errcode(ERRCODE_UNDEFINED_TABLE),
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errmsg("%s \"%s\" does not exist", kind, name)));
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}
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return id;
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}
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