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Files
postgres/src/backend/rewrite/rewriteDefine.c
Tom Lane 110d293a68 Add some errdetail to checkRuleResultList().
This function wasn't originally thought to be really user-facing,
because converting a table to a view isn't something we expect people
to do manually.  So not all that much effort was spent on the error
messages; in particular, while the code will complain that you got
the column types wrong it won't say exactly what they are.  But since
we repurposed the code to also check compatibility of rule RETURNING
lists, it's definitely user-facing.  It now seems worthwhile to add
errdetail messages showing exactly what the conflict is when there's
a mismatch of column names or types.  This is prompted by bug #10836
from Matthias Raffelsieper, which might have been forestalled if the
error message had reported the wrong column type as being "record".

Per Alvaro's advice, back-patch to branches before 9.4, but resist
the temptation to rephrase any existing strings there.  Adding new
strings is not really a translation degradation; anyway having the
info presented in English is better than not having it at all.
2014-07-02 14:20:34 -04:00

982 lines
30 KiB
C

/*-------------------------------------------------------------------------
*
* 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, bool requireColumnNameMatch);
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 */
InvokeObjectPostCreateHook(RewriteRelationId, rewriteObjectId, 0);
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.
* Internal callers can target materialized views, but transformRuleStmt()
* blocks them for users. Don't mention them in the error message.
*/
if (event_relation->rd_rel->relkind != RELKIND_RELATION &&
event_relation->rd_rel->relkind != RELKIND_MATVIEW &&
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,
event_relation->rd_rel->relkind !=
RELKIND_MATVIEW);
/*
* ... 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 &&
event_relation->rd_rel->relkind != RELKIND_MATVIEW)
{
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, 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 used for choosing error messages.
*
* A SELECT targetlist may optionally require that column names match.
*/
static void
checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect,
bool requireColumnNameMatch)
{
ListCell *tllist;
int i;
/* Only a SELECT may require a column name match. */
Assert(isSelect || !requireColumnNameMatch);
i = 0;
foreach(tllist, targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tllist);
Oid tletypid;
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")));
/* Check name match if required; no need for two error texts here */
if (requireColumnNameMatch && 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),
errdetail("SELECT target entry is named \"%s\".",
tle->resname)));
/* Check type match. */
tletypid = exprType((Node *) tle->expr);
if (attr->atttypid != tletypid)
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),
isSelect ?
errdetail("SELECT target entry has type %s, but column has type %s.",
format_type_be(tletypid),
format_type_be(attr->atttypid)) :
errdetail("RETURNING list entry has type %s, but column has type %s.",
format_type_be(tletypid),
format_type_be(attr->atttypid))));
/*
* 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),
isSelect ?
errdetail("SELECT target entry has type %s, but column has type %s.",
format_type_with_typemod(tletypid, tletypmod),
format_type_with_typemod(attr->atttypid,
attr->atttypmod)) :
errdetail("RETURNING list entry has type %s, but column has type %s.",
format_type_with_typemod(tletypid, tletypmod),
format_type_with_typemod(attr->atttypid,
attr->atttypmod))));
}
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;
}
InvokeObjectPostAlterHook(RewriteRelationId,
HeapTupleGetOid(ruletup), 0);
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;
}