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Postgres FD Implementation
Commit 54d6706d authored by Kevin Grittner's avatar Kevin Grittner Committed by Magnus Hagander
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Remove accidentally-committed .orig file.

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src/backend/rewrite/rewriteDefine.c.orig deleted 100644 → 0
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/*-------------------------------------------------------------------------
*
* rewriteDefine.c
* routines for defining a rewrite rule
*
* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/rewrite/rewriteDefine.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/multixact.h"
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_rewrite.h"
#include "catalog/storage.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "parser/parse_utilcmd.h"
#include "rewrite/rewriteDefine.h"
#include "rewrite/rewriteManip.h"
#include "rewrite/rewriteSupport.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
static void checkRuleResultList(List *targetList, TupleDesc resultDesc,
bool isSelect);
static bool setRuleCheckAsUser_walker(Node *node, Oid *context);
static void setRuleCheckAsUser_Query(Query *qry, Oid userid);
/*
* InsertRule -
* takes the arguments and inserts them as a row into the system
* relation "pg_rewrite"
*/
static Oid
InsertRule(char *rulname,
int evtype,
Oid eventrel_oid,
AttrNumber evslot_index,
bool evinstead,
Node *event_qual,
List *action,
bool replace)
{
char *evqual = nodeToString(event_qual);
char *actiontree = nodeToString((Node *) action);
Datum values[Natts_pg_rewrite];
bool nulls[Natts_pg_rewrite];
bool replaces[Natts_pg_rewrite];
NameData rname;
Relation pg_rewrite_desc;
HeapTuple tup,
oldtup;
Oid rewriteObjectId;
ObjectAddress myself,
referenced;
bool is_update = false;
/*
* Set up *nulls and *values arrays
*/
MemSet(nulls, false, sizeof(nulls));
namestrcpy(&rname, rulname);
values[Anum_pg_rewrite_rulename - 1] = NameGetDatum(&rname);
values[Anum_pg_rewrite_ev_class - 1] = ObjectIdGetDatum(eventrel_oid);
values[Anum_pg_rewrite_ev_attr - 1] = Int16GetDatum(evslot_index);
values[Anum_pg_rewrite_ev_type - 1] = CharGetDatum(evtype + '0');
values[Anum_pg_rewrite_ev_enabled - 1] = CharGetDatum(RULE_FIRES_ON_ORIGIN);
values[Anum_pg_rewrite_is_instead - 1] = BoolGetDatum(evinstead);
values[Anum_pg_rewrite_ev_qual - 1] = CStringGetTextDatum(evqual);
values[Anum_pg_rewrite_ev_action - 1] = CStringGetTextDatum(actiontree);
/*
* Ready to store new pg_rewrite tuple
*/
pg_rewrite_desc = heap_open(RewriteRelationId, RowExclusiveLock);
/*
* Check to see if we are replacing an existing tuple
*/
oldtup = SearchSysCache2(RULERELNAME,
ObjectIdGetDatum(eventrel_oid),
PointerGetDatum(rulname));
if (HeapTupleIsValid(oldtup))
{
if (!replace)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("rule \"%s\" for relation \"%s\" already exists",
rulname, get_rel_name(eventrel_oid))));
/*
* When replacing, we don't need to replace every attribute
*/
MemSet(replaces, false, sizeof(replaces));
replaces[Anum_pg_rewrite_ev_attr - 1] = true;
replaces[Anum_pg_rewrite_ev_type - 1] = true;
replaces[Anum_pg_rewrite_is_instead - 1] = true;
replaces[Anum_pg_rewrite_ev_qual - 1] = true;
replaces[Anum_pg_rewrite_ev_action - 1] = true;
tup = heap_modify_tuple(oldtup, RelationGetDescr(pg_rewrite_desc),
values, nulls, replaces);
simple_heap_update(pg_rewrite_desc, &tup->t_self, tup);
ReleaseSysCache(oldtup);
rewriteObjectId = HeapTupleGetOid(tup);
is_update = true;
}
else
{
tup = heap_form_tuple(pg_rewrite_desc->rd_att, values, nulls);
rewriteObjectId = simple_heap_insert(pg_rewrite_desc, tup);
}
/* Need to update indexes in either case */
CatalogUpdateIndexes(pg_rewrite_desc, tup);
heap_freetuple(tup);
/* If replacing, get rid of old dependencies and make new ones */
if (is_update)
deleteDependencyRecordsFor(RewriteRelationId, rewriteObjectId, false);
/*
* Install dependency on rule's relation to ensure it will go away on
* relation deletion. If the rule is ON SELECT, make the dependency
* implicit --- this prevents deleting a view's SELECT rule. Other kinds
* of rules can be AUTO.
*/
myself.classId = RewriteRelationId;
myself.objectId = rewriteObjectId;
myself.objectSubId = 0;
referenced.classId = RelationRelationId;
referenced.objectId = eventrel_oid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced,
(evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);
/*
* Also install dependencies on objects referenced in action and qual.
*/
recordDependencyOnExpr(&myself, (Node *) action, NIL,
DEPENDENCY_NORMAL);
if (event_qual != NULL)
{
/* Find query containing OLD/NEW rtable entries */
Query *qry = (Query *) linitial(action);
qry = getInsertSelectQuery(qry, NULL);
recordDependencyOnExpr(&myself, event_qual, qry->rtable,
DEPENDENCY_NORMAL);
}
/* Post creation hook for new rule */
InvokeObjectAccessHook(OAT_POST_CREATE,
RewriteRelationId, rewriteObjectId, 0, NULL);
heap_close(pg_rewrite_desc, RowExclusiveLock);
return rewriteObjectId;
}
/*
* DefineRule
* Execute a CREATE RULE command.
*/
Oid
DefineRule(RuleStmt *stmt, const char *queryString)
{
List *actions;
Node *whereClause;
Oid relId;
/* Parse analysis. */
transformRuleStmt(stmt, queryString, &actions, &whereClause);
/*
* Find and lock the relation. Lock level should match
* DefineQueryRewrite.
*/
relId = RangeVarGetRelid(stmt->relation, AccessExclusiveLock, false);
/* ... and execute */
return DefineQueryRewrite(stmt->rulename,
relId,
whereClause,
stmt->event,
stmt->instead,
stmt->replace,
actions);
}
/*
* DefineQueryRewrite
* Create a rule
*
* This is essentially the same as DefineRule() except that the rule's
* action and qual have already been passed through parse analysis.
*/
Oid
DefineQueryRewrite(char *rulename,
Oid event_relid,
Node *event_qual,
CmdType event_type,
bool is_instead,
bool replace,
List *action)
{
Relation event_relation;
int event_attno;
ListCell *l;
Query *query;
bool RelisBecomingView = false;
Oid ruleId = InvalidOid;
/*
* If we are installing an ON SELECT rule, we had better grab
* AccessExclusiveLock to ensure no SELECTs are currently running on the
* event relation. For other types of rules, it would be sufficient to
* grab ShareRowExclusiveLock to lock out insert/update/delete actions and
* to ensure that we lock out current CREATE RULE statements; but because
* of race conditions in access to catalog entries, we can't do that yet.
*
* Note that this lock level should match the one used in DefineRule.
*/
event_relation = heap_open(event_relid, AccessExclusiveLock);
/*
* Verify relation is of a type that rules can sensibly be applied to.
*/
if (event_relation->rd_rel->relkind != RELKIND_RELATION &&
event_relation->rd_rel->relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or view",
RelationGetRelationName(event_relation))));
if (!allowSystemTableMods && IsSystemRelation(event_relation))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(event_relation))));
/*
* Check user has permission to apply rules to this relation.
*/
if (!pg_class_ownercheck(event_relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(event_relation));
/*
* No rule actions that modify OLD or NEW
*/
foreach(l, action)
{
query = (Query *) lfirst(l);
if (query->resultRelation == 0)
continue;
/* Don't be fooled by INSERT/SELECT */
if (query != getInsertSelectQuery(query, NULL))
continue;
if (query->resultRelation == PRS2_OLD_VARNO)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("rule actions on OLD are not implemented"),
errhint("Use views or triggers instead.")));
if (query->resultRelation == PRS2_NEW_VARNO)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("rule actions on NEW are not implemented"),
errhint("Use triggers instead.")));
}
if (event_type == CMD_SELECT)
{
/*
* Rules ON SELECT are restricted to view definitions
*
* So there cannot be INSTEAD NOTHING, ...
*/
if (list_length(action) == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("INSTEAD NOTHING rules on SELECT are not implemented"),
errhint("Use views instead.")));
/*
* ... there cannot be multiple actions, ...
*/
if (list_length(action) > 1)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("multiple actions for rules on SELECT are not implemented")));
/*
* ... the one action must be a SELECT, ...
*/
query = (Query *) linitial(action);
if (!is_instead ||
query->commandType != CMD_SELECT ||
query->utilityStmt != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("rules on SELECT must have action INSTEAD SELECT")));
/*
* ... it cannot contain data-modifying WITH ...
*/
if (query->hasModifyingCTE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("rules on SELECT must not contain data-modifying statements in WITH")));
/*
* ... there can be no rule qual, ...
*/
if (event_qual != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("event qualifications are not implemented for rules on SELECT")));
/*
* ... the targetlist of the SELECT action must exactly match the
* event relation, ...
*/
checkRuleResultList(query->targetList,
RelationGetDescr(event_relation),
true);
/*
* ... there must not be another ON SELECT rule already ...
*/
if (!replace && event_relation->rd_rules != NULL)
{
int i;
for (i = 0; i < event_relation->rd_rules->numLocks; i++)
{
RewriteRule *rule;
rule = event_relation->rd_rules->rules[i];
if (rule->event == CMD_SELECT)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("\"%s\" is already a view",
RelationGetRelationName(event_relation))));
}
}
/*
* ... and finally the rule must be named _RETURN.
*/
if (strcmp(rulename, ViewSelectRuleName) != 0)
{
/*
* In versions before 7.3, the expected name was _RETviewname. For
* backwards compatibility with old pg_dump output, accept that
* and silently change it to _RETURN. Since this is just a quick
* backwards-compatibility hack, limit the number of characters
* checked to a few less than NAMEDATALEN; this saves having to
* worry about where a multibyte character might have gotten
* truncated.
*/
if (strncmp(rulename, "_RET", 4) != 0 ||
strncmp(rulename + 4, RelationGetRelationName(event_relation),
NAMEDATALEN - 4 - 4) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("view rule for \"%s\" must be named \"%s\"",
RelationGetRelationName(event_relation),
ViewSelectRuleName)));
rulename = pstrdup(ViewSelectRuleName);
}
/*
* Are we converting a relation to a view?
*
* If so, check that the relation is empty because the storage for the
* relation is going to be deleted. Also insist that the rel not have
* any triggers, indexes, or child tables. (Note: these tests are too
* strict, because they will reject relations that once had such but
* don't anymore. But we don't really care, because this whole
* business of converting relations to views is just a kluge to allow
* dump/reload of views that participate in circular dependencies.)
*/
if (event_relation->rd_rel->relkind != RELKIND_VIEW)
{
HeapScanDesc scanDesc;
scanDesc = heap_beginscan(event_relation, SnapshotNow, 0, NULL);
if (heap_getnext(scanDesc, ForwardScanDirection) != NULL)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not convert table \"%s\" to a view because it is not empty",
RelationGetRelationName(event_relation))));
heap_endscan(scanDesc);
if (event_relation->rd_rel->relhastriggers)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not convert table \"%s\" to a view because it has triggers",
RelationGetRelationName(event_relation)),
errhint("In particular, the table cannot be involved in any foreign key relationships.")));
if (event_relation->rd_rel->relhasindex)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not convert table \"%s\" to a view because it has indexes",
RelationGetRelationName(event_relation))));
if (event_relation->rd_rel->relhassubclass)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not convert table \"%s\" to a view because it has child tables",
RelationGetRelationName(event_relation))));
RelisBecomingView = true;
}
}
else
{
/*
* For non-SELECT rules, a RETURNING list can appear in at most one of
* the actions ... and there can't be any RETURNING list at all in a
* conditional or non-INSTEAD rule. (Actually, there can be at most
* one RETURNING list across all rules on the same event, but it seems
* best to enforce that at rule expansion time.) If there is a
* RETURNING list, it must match the event relation.
*/
bool haveReturning = false;
foreach(l, action)
{
query = (Query *) lfirst(l);
if (!query->returningList)
continue;
if (haveReturning)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot have multiple RETURNING lists in a rule")));
haveReturning = true;
if (event_qual != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("RETURNING lists are not supported in conditional rules")));
if (!is_instead)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("RETURNING lists are not supported in non-INSTEAD rules")));
checkRuleResultList(query->returningList,
RelationGetDescr(event_relation),
false);
}
}
/*
* This rule is allowed - prepare to install it.
*/
event_attno = -1;
/* discard rule if it's null action and not INSTEAD; it's a no-op */
if (action != NIL || is_instead)
{
ruleId = InsertRule(rulename,
event_type,
event_relid,
event_attno,
is_instead,
event_qual,
action,
replace);
/*
* Set pg_class 'relhasrules' field TRUE for event relation.
*
* Important side effect: an SI notice is broadcast to force all
* backends (including me!) to update relcache entries with the new
* rule.
*/
SetRelationRuleStatus(event_relid, true);
}
/* ---------------------------------------------------------------------
* If the relation is becoming a view:
* - delete the associated storage files
* - get rid of any system attributes in pg_attribute; a view shouldn't
* have any of those
* - remove the toast table; there is no need for it anymore, and its
* presence would make vacuum slightly more complicated
* - set relkind to RELKIND_VIEW, and adjust other pg_class fields
* to be appropriate for a view
*
* NB: we had better have AccessExclusiveLock to do this ...
* ---------------------------------------------------------------------
*/
if (RelisBecomingView)
{
Relation relationRelation;
Oid toastrelid;
HeapTuple classTup;
Form_pg_class classForm;
relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
toastrelid = event_relation->rd_rel->reltoastrelid;
/* drop storage while table still looks like a table */
RelationDropStorage(event_relation);
DeleteSystemAttributeTuples(event_relid);
/*
* Drop the toast table if any. (This won't take care of updating
* the toast fields in the relation's own pg_class entry; we handle
* that below.)
*/
if (OidIsValid(toastrelid))
{
ObjectAddress toastobject;
/*
* Delete the dependency of the toast relation on the main
* relation so we can drop the former without dropping the latter.
*/
deleteDependencyRecordsFor(RelationRelationId, toastrelid,
false);
/* Make deletion of dependency record visible */
CommandCounterIncrement();
/* Now drop toast table, including its index */
toastobject.classId = RelationRelationId;
toastobject.objectId = toastrelid;
toastobject.objectSubId = 0;
performDeletion(&toastobject, DROP_RESTRICT,
PERFORM_DELETION_INTERNAL);
}
/*
* SetRelationRuleStatus may have updated the pg_class row, so we must
* advance the command counter before trying to update it again.
*/
CommandCounterIncrement();
/*
* Fix pg_class entry to look like a normal view's, including setting
* the correct relkind and removal of reltoastrelid/reltoastidxid of
* the toast table we potentially removed above.
*/
classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(event_relid));
if (!HeapTupleIsValid(classTup))
elog(ERROR, "cache lookup failed for relation %u", event_relid);
classForm = (Form_pg_class) GETSTRUCT(classTup);
classForm->reltablespace = InvalidOid;
classForm->relpages = 0;
classForm->reltuples = 0;
classForm->relallvisible = 0;
classForm->reltoastrelid = InvalidOid;
classForm->reltoastidxid = InvalidOid;
classForm->relhasindex = false;
classForm->relkind = RELKIND_VIEW;
classForm->relhasoids = false;
classForm->relhaspkey = false;
classForm->relfrozenxid = InvalidTransactionId;
classForm->relminmxid = InvalidMultiXactId;
simple_heap_update(relationRelation, &classTup->t_self, classTup);
CatalogUpdateIndexes(relationRelation, classTup);
heap_freetuple(classTup);
heap_close(relationRelation, RowExclusiveLock);
}
/* Close rel, but keep lock till commit... */
heap_close(event_relation, NoLock);
return ruleId;
}
/*
* checkRuleResultList
* Verify that targetList produces output compatible with a tupledesc
*
* The targetList might be either a SELECT targetlist, or a RETURNING list;
* isSelect tells which. (This is mostly used for choosing error messages,
* but also we don't enforce column name matching for RETURNING.)
*/
static void
checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect)
{
ListCell *tllist;
int i;
i = 0;
foreach(tllist, targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tllist);
int32 tletypmod;
Form_pg_attribute attr;
char *attname;
/* resjunk entries may be ignored */
if (tle->resjunk)
continue;
i++;
if (i > resultDesc->natts)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
isSelect ?
errmsg("SELECT rule's target list has too many entries") :
errmsg("RETURNING list has too many entries")));
attr = resultDesc->attrs[i - 1];
attname = NameStr(attr->attname);
/*
* Disallow dropped columns in the relation. This won't happen in the
* cases we actually care about (namely creating a view via CREATE
* TABLE then CREATE RULE, or adding a RETURNING rule to a view).
* Trying to cope with it is much more trouble than it's worth,
* because we'd have to modify the rule to insert dummy NULLs at the
* right positions.
*/
if (attr->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot convert relation containing dropped columns to view")));
if (isSelect && strcmp(tle->resname, attname) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("SELECT rule's target entry %d has different column name from \"%s\"", i, attname)));
if (attr->atttypid != exprType((Node *) tle->expr))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
isSelect ?
errmsg("SELECT rule's target entry %d has different type from column \"%s\"",
i, attname) :
errmsg("RETURNING list's entry %d has different type from column \"%s\"",
i, attname)));
/*
* Allow typmods to be different only if one of them is -1, ie,
* "unspecified". This is necessary for cases like "numeric", where
* the table will have a filled-in default length but the select
* rule's expression will probably have typmod = -1.
*/
tletypmod = exprTypmod((Node *) tle->expr);
if (attr->atttypmod != tletypmod &&
attr->atttypmod != -1 && tletypmod != -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
isSelect ?
errmsg("SELECT rule's target entry %d has different size from column \"%s\"",
i, attname) :
errmsg("RETURNING list's entry %d has different size from column \"%s\"",
i, attname)));
}
if (i != resultDesc->natts)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
isSelect ?
errmsg("SELECT rule's target list has too few entries") :
errmsg("RETURNING list has too few entries")));
}
/*
* setRuleCheckAsUser
* Recursively scan a query or expression tree and set the checkAsUser
* field to the given userid in all rtable entries.
*
* Note: for a view (ON SELECT rule), the checkAsUser field of the OLD
* RTE entry will be overridden when the view rule is expanded, and the
* checkAsUser field of the NEW entry is irrelevant because that entry's
* requiredPerms bits will always be zero. However, for other types of rules
* it's important to set these fields to match the rule owner. So we just set
* them always.
*/
void
setRuleCheckAsUser(Node *node, Oid userid)
{
(void) setRuleCheckAsUser_walker(node, &userid);
}
static bool
setRuleCheckAsUser_walker(Node *node, Oid *context)
{
if (node == NULL)
return false;
if (IsA(node, Query))
{
setRuleCheckAsUser_Query((Query *) node, *context);
return false;
}
return expression_tree_walker(node, setRuleCheckAsUser_walker,
(void *) context);
}
static void
setRuleCheckAsUser_Query(Query *qry, Oid userid)
{
ListCell *l;
/* Set all the RTEs in this query node */
foreach(l, qry->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
if (rte->rtekind == RTE_SUBQUERY)
{
/* Recurse into subquery in FROM */
setRuleCheckAsUser_Query(rte->subquery, userid);
}
else
rte->checkAsUser = userid;
}
/* Recurse into subquery-in-WITH */
foreach(l, qry->cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
setRuleCheckAsUser_Query((Query *) cte->ctequery, userid);
}
/* If there are sublinks, search for them and process their RTEs */
if (qry->hasSubLinks)
query_tree_walker(qry, setRuleCheckAsUser_walker, (void *) &userid,
QTW_IGNORE_RC_SUBQUERIES);
}
/*
* Change the firing semantics of an existing rule.
*/
void
EnableDisableRule(Relation rel, const char *rulename,
char fires_when)
{
Relation pg_rewrite_desc;
Oid owningRel = RelationGetRelid(rel);
Oid eventRelationOid;
HeapTuple ruletup;
bool changed = false;
/*
* Find the rule tuple to change.
*/
pg_rewrite_desc = heap_open(RewriteRelationId, RowExclusiveLock);
ruletup = SearchSysCacheCopy2(RULERELNAME,
ObjectIdGetDatum(owningRel),
PointerGetDatum(rulename));
if (!HeapTupleIsValid(ruletup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("rule \"%s\" for relation \"%s\" does not exist",
rulename, get_rel_name(owningRel))));
/*
* Verify that the user has appropriate permissions.
*/
eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(ruletup))->ev_class;
Assert(eventRelationOid == owningRel);
if (!pg_class_ownercheck(eventRelationOid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
get_rel_name(eventRelationOid));
/*
* Change ev_enabled if it is different from the desired new state.
*/
if (DatumGetChar(((Form_pg_rewrite) GETSTRUCT(ruletup))->ev_enabled) !=
fires_when)
{
((Form_pg_rewrite) GETSTRUCT(ruletup))->ev_enabled =
CharGetDatum(fires_when);
simple_heap_update(pg_rewrite_desc, &ruletup->t_self, ruletup);
/* keep system catalog indexes current */
CatalogUpdateIndexes(pg_rewrite_desc, ruletup);
changed = true;
}
heap_freetuple(ruletup);
heap_close(pg_rewrite_desc, RowExclusiveLock);
/*
* If we changed anything, broadcast a SI inval message to force each
* backend (including our own!) to rebuild relation's relcache entry.
* Otherwise they will fail to apply the change promptly.
*/
if (changed)
CacheInvalidateRelcache(rel);
}
/*
* Perform permissions and integrity checks before acquiring a relation lock.
*/
static void
RangeVarCallbackForRenameRule(const RangeVar *rv, Oid relid, Oid oldrelid,
void *arg)
{
HeapTuple tuple;
Form_pg_class form;
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tuple))
return; /* concurrently dropped */
form = (Form_pg_class) GETSTRUCT(tuple);
/* only tables and views can have rules */
if (form->relkind != RELKIND_RELATION && form->relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or view", rv->relname)));
if (!allowSystemTableMods && IsSystemClass(form))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
rv->relname)));
/* you must own the table to rename one of its rules */
if (!pg_class_ownercheck(relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, rv->relname);
ReleaseSysCache(tuple);
}
/*
* Rename an existing rewrite rule.
*/
Oid
RenameRewriteRule(RangeVar *relation, const char *oldName,
const char *newName)
{
Oid relid;
Relation targetrel;
Relation pg_rewrite_desc;
HeapTuple ruletup;
Form_pg_rewrite ruleform;
Oid ruleOid;
/*
* Look up name, check permissions, and acquire lock (which we will NOT
* release until end of transaction).
*/
relid = RangeVarGetRelidExtended(relation, AccessExclusiveLock,
false, false,
RangeVarCallbackForRenameRule,
NULL);
/* Have lock already, so just need to build relcache entry. */
targetrel = relation_open(relid, NoLock);
/* Prepare to modify pg_rewrite */
pg_rewrite_desc = heap_open(RewriteRelationId, RowExclusiveLock);
/* Fetch the rule's entry (it had better exist) */
ruletup = SearchSysCacheCopy2(RULERELNAME,
ObjectIdGetDatum(relid),
PointerGetDatum(oldName));
if (!HeapTupleIsValid(ruletup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("rule \"%s\" for relation \"%s\" does not exist",
oldName, RelationGetRelationName(targetrel))));
ruleform = (Form_pg_rewrite) GETSTRUCT(ruletup);
ruleOid = HeapTupleGetOid(ruletup);
/* rule with the new name should not already exist */
if (IsDefinedRewriteRule(relid, newName))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("rule \"%s\" for relation \"%s\" already exists",
newName, RelationGetRelationName(targetrel))));
/*
* We disallow renaming ON SELECT rules, because they should always be
* named "_RETURN".
*/
if (ruleform->ev_type == CMD_SELECT + '0')
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("renaming an ON SELECT rule is not allowed")));
/* OK, do the update */
namestrcpy(&(ruleform->rulename), newName);
simple_heap_update(pg_rewrite_desc, &ruletup->t_self, ruletup);
/* keep system catalog indexes current */
CatalogUpdateIndexes(pg_rewrite_desc, ruletup);
heap_freetuple(ruletup);
heap_close(pg_rewrite_desc, RowExclusiveLock);
/*
* Invalidate relation's relcache entry so that other backends (and this
* one too!) are sent SI message to make them rebuild relcache entries.
* (Ideally this should happen automatically...)
*/
CacheInvalidateRelcache(targetrel);
/*
* Close rel, but keep exclusive lock!
*/
relation_close(targetrel, NoLock);
return ruleOid;
}
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