3507 lines
107 KiB
C
3507 lines
107 KiB
C
/*-------------------------------------------------------------------------
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*
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* rewriteHandler.c
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* Primary module of query rewriter.
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*
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* Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* src/backend/rewrite/rewriteHandler.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/sysattr.h"
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#include "catalog/pg_type.h"
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#include "commands/trigger.h"
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#include "foreign/fdwapi.h"
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#include "nodes/makefuncs.h"
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#include "nodes/nodeFuncs.h"
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#include "parser/analyze.h"
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#include "parser/parse_coerce.h"
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#include "parser/parsetree.h"
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#include "rewrite/rewriteDefine.h"
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#include "rewrite/rewriteHandler.h"
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#include "rewrite/rewriteManip.h"
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#include "rewrite/rowsecurity.h"
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#include "utils/builtins.h"
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#include "utils/lsyscache.h"
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#include "utils/rel.h"
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/* We use a list of these to detect recursion in RewriteQuery */
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typedef struct rewrite_event
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{
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Oid relation; /* OID of relation having rules */
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CmdType event; /* type of rule being fired */
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} rewrite_event;
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typedef struct acquireLocksOnSubLinks_context
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{
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bool for_execute; /* AcquireRewriteLocks' forExecute param */
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} acquireLocksOnSubLinks_context;
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static bool acquireLocksOnSubLinks(Node *node,
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acquireLocksOnSubLinks_context *context);
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static Query *rewriteRuleAction(Query *parsetree,
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Query *rule_action,
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Node *rule_qual,
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int rt_index,
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CmdType event,
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bool *returning_flag);
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static List *adjustJoinTreeList(Query *parsetree, bool removert, int rt_index);
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static List *rewriteTargetListIU(List *targetList,
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CmdType commandType,
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Relation target_relation,
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int result_rti,
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List **attrno_list);
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static TargetEntry *process_matched_tle(TargetEntry *src_tle,
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TargetEntry *prior_tle,
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const char *attrName);
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static Node *get_assignment_input(Node *node);
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static void rewriteValuesRTE(RangeTblEntry *rte, Relation target_relation,
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List *attrnos);
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static void rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
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Relation target_relation);
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static void markQueryForLocking(Query *qry, Node *jtnode,
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LockClauseStrength strength, LockWaitPolicy waitPolicy,
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bool pushedDown);
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static List *matchLocks(CmdType event, RuleLock *rulelocks,
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int varno, Query *parsetree, bool *hasUpdate);
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static Query *fireRIRrules(Query *parsetree, List *activeRIRs,
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bool forUpdatePushedDown);
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static bool view_has_instead_trigger(Relation view, CmdType event);
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static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
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/*
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* AcquireRewriteLocks -
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* Acquire suitable locks on all the relations mentioned in the Query.
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* These locks will ensure that the relation schemas don't change under us
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* while we are rewriting and planning the query.
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*
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* forExecute indicates that the query is about to be executed.
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* If so, we'll acquire RowExclusiveLock on the query's resultRelation,
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* RowShareLock on any relation accessed FOR [KEY] UPDATE/SHARE, and
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* AccessShareLock on all other relations mentioned.
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*
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* If forExecute is false, AccessShareLock is acquired on all relations.
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* This case is suitable for ruleutils.c, for example, where we only need
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* schema stability and we don't intend to actually modify any relations.
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*
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* forUpdatePushedDown indicates that a pushed-down FOR [KEY] UPDATE/SHARE
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* applies to the current subquery, requiring all rels to be opened with at
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* least RowShareLock. This should always be false at the top of the
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* recursion. This flag is ignored if forExecute is false.
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*
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* A secondary purpose of this routine is to fix up JOIN RTE references to
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* dropped columns (see details below). Because the RTEs are modified in
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* place, it is generally appropriate for the caller of this routine to have
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* first done a copyObject() to make a writable copy of the querytree in the
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* current memory context.
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*
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* This processing can, and for efficiency's sake should, be skipped when the
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* querytree has just been built by the parser: parse analysis already got
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* all the same locks we'd get here, and the parser will have omitted dropped
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* columns from JOINs to begin with. But we must do this whenever we are
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* dealing with a querytree produced earlier than the current command.
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*
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* About JOINs and dropped columns: although the parser never includes an
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* already-dropped column in a JOIN RTE's alias var list, it is possible for
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* such a list in a stored rule to include references to dropped columns.
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* (If the column is not explicitly referenced anywhere else in the query,
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* the dependency mechanism won't consider it used by the rule and so won't
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* prevent the column drop.) To support get_rte_attribute_is_dropped(), we
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* replace join alias vars that reference dropped columns with null pointers.
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*
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* (In PostgreSQL 8.0, we did not do this processing but instead had
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* get_rte_attribute_is_dropped() recurse to detect dropped columns in joins.
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* That approach had horrible performance unfortunately; in particular
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* construction of a nested join was O(N^2) in the nesting depth.)
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*/
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void
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AcquireRewriteLocks(Query *parsetree,
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bool forExecute,
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bool forUpdatePushedDown)
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{
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ListCell *l;
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int rt_index;
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acquireLocksOnSubLinks_context context;
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context.for_execute = forExecute;
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/*
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* First, process RTEs of the current query level.
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*/
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rt_index = 0;
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foreach(l, parsetree->rtable)
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{
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RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
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Relation rel;
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LOCKMODE lockmode;
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List *newaliasvars;
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Index curinputvarno;
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RangeTblEntry *curinputrte;
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ListCell *ll;
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++rt_index;
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switch (rte->rtekind)
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{
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case RTE_RELATION:
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/*
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* Grab the appropriate lock type for the relation, and do not
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* release it until end of transaction. This protects the
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* rewriter and planner against schema changes mid-query.
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*
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* Assuming forExecute is true, this logic must match what the
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* executor will do, else we risk lock-upgrade deadlocks.
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*/
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if (!forExecute)
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lockmode = AccessShareLock;
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else if (rt_index == parsetree->resultRelation)
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lockmode = RowExclusiveLock;
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else if (forUpdatePushedDown ||
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get_parse_rowmark(parsetree, rt_index) != NULL)
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lockmode = RowShareLock;
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else
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lockmode = AccessShareLock;
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rel = heap_open(rte->relid, lockmode);
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/*
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* While we have the relation open, update the RTE's relkind,
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* just in case it changed since this rule was made.
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*/
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rte->relkind = rel->rd_rel->relkind;
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heap_close(rel, NoLock);
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break;
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case RTE_JOIN:
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/*
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* Scan the join's alias var list to see if any columns have
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* been dropped, and if so replace those Vars with null
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* pointers.
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*
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* Since a join has only two inputs, we can expect to see
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* multiple references to the same input RTE; optimize away
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* multiple fetches.
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*/
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newaliasvars = NIL;
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curinputvarno = 0;
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curinputrte = NULL;
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foreach(ll, rte->joinaliasvars)
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{
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Var *aliasitem = (Var *) lfirst(ll);
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Var *aliasvar = aliasitem;
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/* Look through any implicit coercion */
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aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
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/*
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* If the list item isn't a simple Var, then it must
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* represent a merged column, ie a USING column, and so it
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* couldn't possibly be dropped, since it's referenced in
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* the join clause. (Conceivably it could also be a null
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* pointer already? But that's OK too.)
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*/
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if (aliasvar && IsA(aliasvar, Var))
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{
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/*
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* The elements of an alias list have to refer to
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* earlier RTEs of the same rtable, because that's the
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* order the planner builds things in. So we already
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* processed the referenced RTE, and so it's safe to
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* use get_rte_attribute_is_dropped on it. (This might
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* not hold after rewriting or planning, but it's OK
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* to assume here.)
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*/
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Assert(aliasvar->varlevelsup == 0);
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if (aliasvar->varno != curinputvarno)
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{
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curinputvarno = aliasvar->varno;
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if (curinputvarno >= rt_index)
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elog(ERROR, "unexpected varno %d in JOIN RTE %d",
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curinputvarno, rt_index);
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curinputrte = rt_fetch(curinputvarno,
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parsetree->rtable);
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}
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if (get_rte_attribute_is_dropped(curinputrte,
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aliasvar->varattno))
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{
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/* Replace the join alias item with a NULL */
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aliasitem = NULL;
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}
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}
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newaliasvars = lappend(newaliasvars, aliasitem);
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}
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rte->joinaliasvars = newaliasvars;
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break;
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case RTE_SUBQUERY:
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/*
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* The subquery RTE itself is all right, but we have to
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* recurse to process the represented subquery.
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*/
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AcquireRewriteLocks(rte->subquery,
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forExecute,
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(forUpdatePushedDown ||
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get_parse_rowmark(parsetree, rt_index) != NULL));
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break;
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default:
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/* ignore other types of RTEs */
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break;
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}
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}
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/* Recurse into subqueries in WITH */
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foreach(l, parsetree->cteList)
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{
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CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
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AcquireRewriteLocks((Query *) cte->ctequery, forExecute, false);
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}
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/*
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* Recurse into sublink subqueries, too. But we already did the ones in
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* the rtable and cteList.
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*/
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if (parsetree->hasSubLinks)
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query_tree_walker(parsetree, acquireLocksOnSubLinks, &context,
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QTW_IGNORE_RC_SUBQUERIES);
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}
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/*
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* Walker to find sublink subqueries for AcquireRewriteLocks
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*/
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static bool
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acquireLocksOnSubLinks(Node *node, acquireLocksOnSubLinks_context *context)
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{
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if (node == NULL)
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return false;
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if (IsA(node, SubLink))
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{
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SubLink *sub = (SubLink *) node;
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/* Do what we came for */
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AcquireRewriteLocks((Query *) sub->subselect,
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context->for_execute,
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false);
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/* Fall through to process lefthand args of SubLink */
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}
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/*
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* Do NOT recurse into Query nodes, because AcquireRewriteLocks already
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* processed subselects of subselects for us.
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*/
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return expression_tree_walker(node, acquireLocksOnSubLinks, context);
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}
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/*
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* rewriteRuleAction -
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* Rewrite the rule action with appropriate qualifiers (taken from
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* the triggering query).
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*
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* Input arguments:
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* parsetree - original query
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* rule_action - one action (query) of a rule
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* rule_qual - WHERE condition of rule, or NULL if unconditional
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* rt_index - RT index of result relation in original query
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* event - type of rule event
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* Output arguments:
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* *returning_flag - set TRUE if we rewrite RETURNING clause in rule_action
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* (must be initialized to FALSE)
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* Return value:
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* rewritten form of rule_action
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*/
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static Query *
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rewriteRuleAction(Query *parsetree,
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Query *rule_action,
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Node *rule_qual,
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int rt_index,
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CmdType event,
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bool *returning_flag)
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{
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int current_varno,
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new_varno;
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int rt_length;
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Query *sub_action;
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Query **sub_action_ptr;
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acquireLocksOnSubLinks_context context;
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context.for_execute = true;
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/*
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* Make modifiable copies of rule action and qual (what we're passed are
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* the stored versions in the relcache; don't touch 'em!).
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*/
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rule_action = (Query *) copyObject(rule_action);
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rule_qual = (Node *) copyObject(rule_qual);
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/*
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* Acquire necessary locks and fix any deleted JOIN RTE entries.
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*/
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AcquireRewriteLocks(rule_action, true, false);
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(void) acquireLocksOnSubLinks(rule_qual, &context);
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current_varno = rt_index;
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rt_length = list_length(parsetree->rtable);
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new_varno = PRS2_NEW_VARNO + rt_length;
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/*
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* Adjust rule action and qual to offset its varnos, so that we can merge
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* its rtable with the main parsetree's rtable.
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*
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* If the rule action is an INSERT...SELECT, the OLD/NEW rtable entries
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* will be in the SELECT part, and we have to modify that rather than the
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* top-level INSERT (kluge!).
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*/
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sub_action = getInsertSelectQuery(rule_action, &sub_action_ptr);
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OffsetVarNodes((Node *) sub_action, rt_length, 0);
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OffsetVarNodes(rule_qual, rt_length, 0);
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/* but references to OLD should point at original rt_index */
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ChangeVarNodes((Node *) sub_action,
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PRS2_OLD_VARNO + rt_length, rt_index, 0);
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ChangeVarNodes(rule_qual,
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PRS2_OLD_VARNO + rt_length, rt_index, 0);
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/*
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* Generate expanded rtable consisting of main parsetree's rtable plus
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* rule action's rtable; this becomes the complete rtable for the rule
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* action. Some of the entries may be unused after we finish rewriting,
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* but we leave them all in place for two reasons:
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*
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* We'd have a much harder job to adjust the query's varnos if we
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* selectively removed RT entries.
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*
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* If the rule is INSTEAD, then the original query won't be executed at
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* all, and so its rtable must be preserved so that the executor will do
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* the correct permissions checks on it.
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*
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* RT entries that are not referenced in the completed jointree will be
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* ignored by the planner, so they do not affect query semantics. But any
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* permissions checks specified in them will be applied during executor
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* startup (see ExecCheckRTEPerms()). This allows us to check that the
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* caller has, say, insert-permission on a view, when the view is not
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* semantically referenced at all in the resulting query.
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*
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* When a rule is not INSTEAD, the permissions checks done on its copied
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* RT entries will be redundant with those done during execution of the
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* original query, but we don't bother to treat that case differently.
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*
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* NOTE: because planner will destructively alter rtable, we must ensure
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* that rule action's rtable is separate and shares no substructure with
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* the main rtable. Hence do a deep copy here.
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*/
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sub_action->rtable = list_concat((List *) copyObject(parsetree->rtable),
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sub_action->rtable);
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/*
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* There could have been some SubLinks in parsetree's rtable, in which
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* case we'd better mark the sub_action correctly.
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*/
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if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
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{
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ListCell *lc;
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foreach(lc, parsetree->rtable)
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{
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RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
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switch (rte->rtekind)
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{
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case RTE_RELATION:
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sub_action->hasSubLinks =
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checkExprHasSubLink((Node *) rte->tablesample);
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break;
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case RTE_FUNCTION:
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sub_action->hasSubLinks =
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checkExprHasSubLink((Node *) rte->functions);
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break;
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case RTE_VALUES:
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sub_action->hasSubLinks =
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checkExprHasSubLink((Node *) rte->values_lists);
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break;
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default:
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/* other RTE types don't contain bare expressions */
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break;
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}
|
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if (sub_action->hasSubLinks)
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break; /* no need to keep scanning rtable */
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}
|
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}
|
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|
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/*
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* Each rule action's jointree should be the main parsetree's jointree
|
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* plus that rule's jointree, but usually *without* the original rtindex
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* that we're replacing (if present, which it won't be for INSERT). Note
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* that if the rule action refers to OLD, its jointree will add a
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* reference to rt_index. If the rule action doesn't refer to OLD, but
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* either the rule_qual or the user query quals do, then we need to keep
|
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* the original rtindex in the jointree to provide data for the quals. We
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* don't want the original rtindex to be joined twice, however, so avoid
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* keeping it if the rule action mentions it.
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*
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* As above, the action's jointree must not share substructure with the
|
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* main parsetree's.
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*/
|
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if (sub_action->commandType != CMD_UTILITY)
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{
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bool keeporig;
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List *newjointree;
|
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Assert(sub_action->jointree != NULL);
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keeporig = (!rangeTableEntry_used((Node *) sub_action->jointree,
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rt_index, 0)) &&
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(rangeTableEntry_used(rule_qual, rt_index, 0) ||
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rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
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newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
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if (newjointree != NIL)
|
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{
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/*
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* If sub_action is a setop, manipulating its jointree will do no
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* good at all, because the jointree is dummy. (Perhaps someday
|
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* we could push the joining and quals down to the member
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* statements of the setop?)
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*/
|
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if (sub_action->setOperations != NULL)
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
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sub_action->jointree->fromlist =
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list_concat(newjointree, sub_action->jointree->fromlist);
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|
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/*
|
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* There could have been some SubLinks in newjointree, in which
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* case we'd better mark the sub_action correctly.
|
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*/
|
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if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
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sub_action->hasSubLinks =
|
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checkExprHasSubLink((Node *) newjointree);
|
|
}
|
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}
|
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|
|
/*
|
|
* If the original query has any CTEs, copy them into the rule action. But
|
|
* we don't need them for a utility action.
|
|
*/
|
|
if (parsetree->cteList != NIL && sub_action->commandType != CMD_UTILITY)
|
|
{
|
|
ListCell *lc;
|
|
|
|
/*
|
|
* Annoying implementation restriction: because CTEs are identified by
|
|
* name within a cteList, we can't merge a CTE from the original query
|
|
* if it has the same name as any CTE in the rule action.
|
|
*
|
|
* This could possibly be fixed by using some sort of internally
|
|
* generated ID, instead of names, to link CTE RTEs to their CTEs.
|
|
*/
|
|
foreach(lc, parsetree->cteList)
|
|
{
|
|
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
|
|
ListCell *lc2;
|
|
|
|
foreach(lc2, sub_action->cteList)
|
|
{
|
|
CommonTableExpr *cte2 = (CommonTableExpr *) lfirst(lc2);
|
|
|
|
if (strcmp(cte->ctename, cte2->ctename) == 0)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("WITH query name \"%s\" appears in both a rule action and the query being rewritten",
|
|
cte->ctename)));
|
|
}
|
|
}
|
|
|
|
/* OK, it's safe to combine the CTE lists */
|
|
sub_action->cteList = list_concat(sub_action->cteList,
|
|
copyObject(parsetree->cteList));
|
|
}
|
|
|
|
/*
|
|
* Event Qualification forces copying of parsetree and splitting into two
|
|
* queries one w/rule_qual, one w/NOT rule_qual. Also add user query qual
|
|
* onto rule action
|
|
*/
|
|
AddQual(sub_action, rule_qual);
|
|
|
|
AddQual(sub_action, parsetree->jointree->quals);
|
|
|
|
/*
|
|
* Rewrite new.attribute with right hand side of target-list entry for
|
|
* appropriate field name in insert/update.
|
|
*
|
|
* KLUGE ALERT: since ReplaceVarsFromTargetList returns a mutated copy, we
|
|
* can't just apply it to sub_action; we have to remember to update the
|
|
* sublink inside rule_action, too.
|
|
*/
|
|
if ((event == CMD_INSERT || event == CMD_UPDATE) &&
|
|
sub_action->commandType != CMD_UTILITY)
|
|
{
|
|
sub_action = (Query *)
|
|
ReplaceVarsFromTargetList((Node *) sub_action,
|
|
new_varno,
|
|
0,
|
|
rt_fetch(new_varno, sub_action->rtable),
|
|
parsetree->targetList,
|
|
(event == CMD_UPDATE) ?
|
|
REPLACEVARS_CHANGE_VARNO :
|
|
REPLACEVARS_SUBSTITUTE_NULL,
|
|
current_varno,
|
|
NULL);
|
|
if (sub_action_ptr)
|
|
*sub_action_ptr = sub_action;
|
|
else
|
|
rule_action = sub_action;
|
|
}
|
|
|
|
/*
|
|
* If rule_action has a RETURNING clause, then either throw it away if the
|
|
* triggering query has no RETURNING clause, or rewrite it to emit what
|
|
* the triggering query's RETURNING clause asks for. Throw an error if
|
|
* more than one rule has a RETURNING clause.
|
|
*/
|
|
if (!parsetree->returningList)
|
|
rule_action->returningList = NIL;
|
|
else if (rule_action->returningList)
|
|
{
|
|
if (*returning_flag)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot have RETURNING lists in multiple rules")));
|
|
*returning_flag = true;
|
|
rule_action->returningList = (List *)
|
|
ReplaceVarsFromTargetList((Node *) parsetree->returningList,
|
|
parsetree->resultRelation,
|
|
0,
|
|
rt_fetch(parsetree->resultRelation,
|
|
parsetree->rtable),
|
|
rule_action->returningList,
|
|
REPLACEVARS_REPORT_ERROR,
|
|
0,
|
|
&rule_action->hasSubLinks);
|
|
|
|
/*
|
|
* There could have been some SubLinks in parsetree's returningList,
|
|
* in which case we'd better mark the rule_action correctly.
|
|
*/
|
|
if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
|
|
rule_action->hasSubLinks =
|
|
checkExprHasSubLink((Node *) rule_action->returningList);
|
|
}
|
|
|
|
return rule_action;
|
|
}
|
|
|
|
/*
|
|
* Copy the query's jointree list, and optionally attempt to remove any
|
|
* occurrence of the given rt_index as a top-level join item (we do not look
|
|
* for it within join items; this is OK because we are only expecting to find
|
|
* it as an UPDATE or DELETE target relation, which will be at the top level
|
|
* of the join). Returns modified jointree list --- this is a separate copy
|
|
* sharing no nodes with the original.
|
|
*/
|
|
static List *
|
|
adjustJoinTreeList(Query *parsetree, bool removert, int rt_index)
|
|
{
|
|
List *newjointree = copyObject(parsetree->jointree->fromlist);
|
|
ListCell *l;
|
|
|
|
if (removert)
|
|
{
|
|
foreach(l, newjointree)
|
|
{
|
|
RangeTblRef *rtr = lfirst(l);
|
|
|
|
if (IsA(rtr, RangeTblRef) &&
|
|
rtr->rtindex == rt_index)
|
|
{
|
|
newjointree = list_delete_ptr(newjointree, rtr);
|
|
|
|
/*
|
|
* foreach is safe because we exit loop after list_delete...
|
|
*/
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
return newjointree;
|
|
}
|
|
|
|
|
|
/*
|
|
* rewriteTargetListIU - rewrite INSERT/UPDATE targetlist into standard form
|
|
*
|
|
* This has the following responsibilities:
|
|
*
|
|
* 1. For an INSERT, add tlist entries to compute default values for any
|
|
* attributes that have defaults and are not assigned to in the given tlist.
|
|
* (We do not insert anything for default-less attributes, however. The
|
|
* planner will later insert NULLs for them, but there's no reason to slow
|
|
* down rewriter processing with extra tlist nodes.) Also, for both INSERT
|
|
* and UPDATE, replace explicit DEFAULT specifications with column default
|
|
* expressions.
|
|
*
|
|
* 2. For an UPDATE on a trigger-updatable view, add tlist entries for any
|
|
* unassigned-to attributes, assigning them their old values. These will
|
|
* later get expanded to the output values of the view. (This is equivalent
|
|
* to what the planner's expand_targetlist() will do for UPDATE on a regular
|
|
* table, but it's more convenient to do it here while we still have easy
|
|
* access to the view's original RT index.) This is only necessary for
|
|
* trigger-updatable views, for which the view remains the result relation of
|
|
* the query. For auto-updatable views we must not do this, since it might
|
|
* add assignments to non-updatable view columns. For rule-updatable views it
|
|
* is unnecessary extra work, since the query will be rewritten with a
|
|
* different result relation which will be processed when we recurse via
|
|
* RewriteQuery.
|
|
*
|
|
* 3. Merge multiple entries for the same target attribute, or declare error
|
|
* if we can't. Multiple entries are only allowed for INSERT/UPDATE of
|
|
* portions of an array or record field, for example
|
|
* UPDATE table SET foo[2] = 42, foo[4] = 43;
|
|
* We can merge such operations into a single assignment op. Essentially,
|
|
* the expression we want to produce in this case is like
|
|
* foo = array_set_element(array_set_element(foo, 2, 42), 4, 43)
|
|
*
|
|
* 4. Sort the tlist into standard order: non-junk fields in order by resno,
|
|
* then junk fields (these in no particular order).
|
|
*
|
|
* We must do items 1,2,3 before firing rewrite rules, else rewritten
|
|
* references to NEW.foo will produce wrong or incomplete results. Item 4
|
|
* is not needed for rewriting, but will be needed by the planner, and we
|
|
* can do it essentially for free while handling the other items.
|
|
*
|
|
* If attrno_list isn't NULL, we return an additional output besides the
|
|
* rewritten targetlist: an integer list of the assigned-to attnums, in
|
|
* order of the original tlist's non-junk entries. This is needed for
|
|
* processing VALUES RTEs.
|
|
*/
|
|
static List *
|
|
rewriteTargetListIU(List *targetList,
|
|
CmdType commandType,
|
|
Relation target_relation,
|
|
int result_rti,
|
|
List **attrno_list)
|
|
{
|
|
TargetEntry **new_tles;
|
|
List *new_tlist = NIL;
|
|
List *junk_tlist = NIL;
|
|
Form_pg_attribute att_tup;
|
|
int attrno,
|
|
next_junk_attrno,
|
|
numattrs;
|
|
ListCell *temp;
|
|
|
|
if (attrno_list) /* initialize optional result list */
|
|
*attrno_list = NIL;
|
|
|
|
/*
|
|
* We process the normal (non-junk) attributes by scanning the input tlist
|
|
* once and transferring TLEs into an array, then scanning the array to
|
|
* build an output tlist. This avoids O(N^2) behavior for large numbers
|
|
* of attributes.
|
|
*
|
|
* Junk attributes are tossed into a separate list during the same tlist
|
|
* scan, then appended to the reconstructed tlist.
|
|
*/
|
|
numattrs = RelationGetNumberOfAttributes(target_relation);
|
|
new_tles = (TargetEntry **) palloc0(numattrs * sizeof(TargetEntry *));
|
|
next_junk_attrno = numattrs + 1;
|
|
|
|
foreach(temp, targetList)
|
|
{
|
|
TargetEntry *old_tle = (TargetEntry *) lfirst(temp);
|
|
|
|
if (!old_tle->resjunk)
|
|
{
|
|
/* Normal attr: stash it into new_tles[] */
|
|
attrno = old_tle->resno;
|
|
if (attrno < 1 || attrno > numattrs)
|
|
elog(ERROR, "bogus resno %d in targetlist", attrno);
|
|
att_tup = target_relation->rd_att->attrs[attrno - 1];
|
|
|
|
/* put attrno into attrno_list even if it's dropped */
|
|
if (attrno_list)
|
|
*attrno_list = lappend_int(*attrno_list, attrno);
|
|
|
|
/* We can (and must) ignore deleted attributes */
|
|
if (att_tup->attisdropped)
|
|
continue;
|
|
|
|
/* Merge with any prior assignment to same attribute */
|
|
new_tles[attrno - 1] =
|
|
process_matched_tle(old_tle,
|
|
new_tles[attrno - 1],
|
|
NameStr(att_tup->attname));
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* Copy all resjunk tlist entries to junk_tlist, and assign them
|
|
* resnos above the last real resno.
|
|
*
|
|
* Typical junk entries include ORDER BY or GROUP BY expressions
|
|
* (are these actually possible in an INSERT or UPDATE?), system
|
|
* attribute references, etc.
|
|
*/
|
|
|
|
/* Get the resno right, but don't copy unnecessarily */
|
|
if (old_tle->resno != next_junk_attrno)
|
|
{
|
|
old_tle = flatCopyTargetEntry(old_tle);
|
|
old_tle->resno = next_junk_attrno;
|
|
}
|
|
junk_tlist = lappend(junk_tlist, old_tle);
|
|
next_junk_attrno++;
|
|
}
|
|
}
|
|
|
|
for (attrno = 1; attrno <= numattrs; attrno++)
|
|
{
|
|
TargetEntry *new_tle = new_tles[attrno - 1];
|
|
|
|
att_tup = target_relation->rd_att->attrs[attrno - 1];
|
|
|
|
/* We can (and must) ignore deleted attributes */
|
|
if (att_tup->attisdropped)
|
|
continue;
|
|
|
|
/*
|
|
* Handle the two cases where we need to insert a default expression:
|
|
* it's an INSERT and there's no tlist entry for the column, or the
|
|
* tlist entry is a DEFAULT placeholder node.
|
|
*/
|
|
if ((new_tle == NULL && commandType == CMD_INSERT) ||
|
|
(new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)))
|
|
{
|
|
Node *new_expr;
|
|
|
|
new_expr = build_column_default(target_relation, attrno);
|
|
|
|
/*
|
|
* If there is no default (ie, default is effectively NULL), we
|
|
* can omit the tlist entry in the INSERT case, since the planner
|
|
* can insert a NULL for itself, and there's no point in spending
|
|
* any more rewriter cycles on the entry. But in the UPDATE case
|
|
* we've got to explicitly set the column to NULL.
|
|
*/
|
|
if (!new_expr)
|
|
{
|
|
if (commandType == CMD_INSERT)
|
|
new_tle = NULL;
|
|
else
|
|
{
|
|
new_expr = (Node *) makeConst(att_tup->atttypid,
|
|
-1,
|
|
att_tup->attcollation,
|
|
att_tup->attlen,
|
|
(Datum) 0,
|
|
true, /* isnull */
|
|
att_tup->attbyval);
|
|
/* this is to catch a NOT NULL domain constraint */
|
|
new_expr = coerce_to_domain(new_expr,
|
|
InvalidOid, -1,
|
|
att_tup->atttypid,
|
|
COERCE_IMPLICIT_CAST,
|
|
-1,
|
|
false,
|
|
false);
|
|
}
|
|
}
|
|
|
|
if (new_expr)
|
|
new_tle = makeTargetEntry((Expr *) new_expr,
|
|
attrno,
|
|
pstrdup(NameStr(att_tup->attname)),
|
|
false);
|
|
}
|
|
|
|
/*
|
|
* For an UPDATE on a trigger-updatable view, provide a dummy entry
|
|
* whenever there is no explicit assignment.
|
|
*/
|
|
if (new_tle == NULL && commandType == CMD_UPDATE &&
|
|
target_relation->rd_rel->relkind == RELKIND_VIEW &&
|
|
view_has_instead_trigger(target_relation, CMD_UPDATE))
|
|
{
|
|
Node *new_expr;
|
|
|
|
new_expr = (Node *) makeVar(result_rti,
|
|
attrno,
|
|
att_tup->atttypid,
|
|
att_tup->atttypmod,
|
|
att_tup->attcollation,
|
|
0);
|
|
|
|
new_tle = makeTargetEntry((Expr *) new_expr,
|
|
attrno,
|
|
pstrdup(NameStr(att_tup->attname)),
|
|
false);
|
|
}
|
|
|
|
if (new_tle)
|
|
new_tlist = lappend(new_tlist, new_tle);
|
|
}
|
|
|
|
pfree(new_tles);
|
|
|
|
return list_concat(new_tlist, junk_tlist);
|
|
}
|
|
|
|
|
|
/*
|
|
* Convert a matched TLE from the original tlist into a correct new TLE.
|
|
*
|
|
* This routine detects and handles multiple assignments to the same target
|
|
* attribute. (The attribute name is needed only for error messages.)
|
|
*/
|
|
static TargetEntry *
|
|
process_matched_tle(TargetEntry *src_tle,
|
|
TargetEntry *prior_tle,
|
|
const char *attrName)
|
|
{
|
|
TargetEntry *result;
|
|
Node *src_expr;
|
|
Node *prior_expr;
|
|
Node *src_input;
|
|
Node *prior_input;
|
|
Node *priorbottom;
|
|
Node *newexpr;
|
|
|
|
if (prior_tle == NULL)
|
|
{
|
|
/*
|
|
* Normal case where this is the first assignment to the attribute.
|
|
*/
|
|
return src_tle;
|
|
}
|
|
|
|
/*----------
|
|
* Multiple assignments to same attribute. Allow only if all are
|
|
* FieldStore or ArrayRef assignment operations. This is a bit
|
|
* tricky because what we may actually be looking at is a nest of
|
|
* such nodes; consider
|
|
* UPDATE tab SET col.fld1.subfld1 = x, col.fld2.subfld2 = y
|
|
* The two expressions produced by the parser will look like
|
|
* FieldStore(col, fld1, FieldStore(placeholder, subfld1, x))
|
|
* FieldStore(col, fld2, FieldStore(placeholder, subfld2, y))
|
|
* However, we can ignore the substructure and just consider the top
|
|
* FieldStore or ArrayRef from each assignment, because it works to
|
|
* combine these as
|
|
* FieldStore(FieldStore(col, fld1,
|
|
* FieldStore(placeholder, subfld1, x)),
|
|
* fld2, FieldStore(placeholder, subfld2, y))
|
|
* Note the leftmost expression goes on the inside so that the
|
|
* assignments appear to occur left-to-right.
|
|
*
|
|
* For FieldStore, instead of nesting we can generate a single
|
|
* FieldStore with multiple target fields. We must nest when
|
|
* ArrayRefs are involved though.
|
|
*----------
|
|
*/
|
|
src_expr = (Node *) src_tle->expr;
|
|
prior_expr = (Node *) prior_tle->expr;
|
|
src_input = get_assignment_input(src_expr);
|
|
prior_input = get_assignment_input(prior_expr);
|
|
if (src_input == NULL ||
|
|
prior_input == NULL ||
|
|
exprType(src_expr) != exprType(prior_expr))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_SYNTAX_ERROR),
|
|
errmsg("multiple assignments to same column \"%s\"",
|
|
attrName)));
|
|
|
|
/*
|
|
* Prior TLE could be a nest of assignments if we do this more than once.
|
|
*/
|
|
priorbottom = prior_input;
|
|
for (;;)
|
|
{
|
|
Node *newbottom = get_assignment_input(priorbottom);
|
|
|
|
if (newbottom == NULL)
|
|
break; /* found the original Var reference */
|
|
priorbottom = newbottom;
|
|
}
|
|
if (!equal(priorbottom, src_input))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_SYNTAX_ERROR),
|
|
errmsg("multiple assignments to same column \"%s\"",
|
|
attrName)));
|
|
|
|
/*
|
|
* Looks OK to nest 'em.
|
|
*/
|
|
if (IsA(src_expr, FieldStore))
|
|
{
|
|
FieldStore *fstore = makeNode(FieldStore);
|
|
|
|
if (IsA(prior_expr, FieldStore))
|
|
{
|
|
/* combine the two */
|
|
memcpy(fstore, prior_expr, sizeof(FieldStore));
|
|
fstore->newvals =
|
|
list_concat(list_copy(((FieldStore *) prior_expr)->newvals),
|
|
list_copy(((FieldStore *) src_expr)->newvals));
|
|
fstore->fieldnums =
|
|
list_concat(list_copy(((FieldStore *) prior_expr)->fieldnums),
|
|
list_copy(((FieldStore *) src_expr)->fieldnums));
|
|
}
|
|
else
|
|
{
|
|
/* general case, just nest 'em */
|
|
memcpy(fstore, src_expr, sizeof(FieldStore));
|
|
fstore->arg = (Expr *) prior_expr;
|
|
}
|
|
newexpr = (Node *) fstore;
|
|
}
|
|
else if (IsA(src_expr, ArrayRef))
|
|
{
|
|
ArrayRef *aref = makeNode(ArrayRef);
|
|
|
|
memcpy(aref, src_expr, sizeof(ArrayRef));
|
|
aref->refexpr = (Expr *) prior_expr;
|
|
newexpr = (Node *) aref;
|
|
}
|
|
else
|
|
{
|
|
elog(ERROR, "cannot happen");
|
|
newexpr = NULL;
|
|
}
|
|
|
|
result = flatCopyTargetEntry(src_tle);
|
|
result->expr = (Expr *) newexpr;
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* If node is an assignment node, return its input; else return NULL
|
|
*/
|
|
static Node *
|
|
get_assignment_input(Node *node)
|
|
{
|
|
if (node == NULL)
|
|
return NULL;
|
|
if (IsA(node, FieldStore))
|
|
{
|
|
FieldStore *fstore = (FieldStore *) node;
|
|
|
|
return (Node *) fstore->arg;
|
|
}
|
|
else if (IsA(node, ArrayRef))
|
|
{
|
|
ArrayRef *aref = (ArrayRef *) node;
|
|
|
|
if (aref->refassgnexpr == NULL)
|
|
return NULL;
|
|
return (Node *) aref->refexpr;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Make an expression tree for the default value for a column.
|
|
*
|
|
* If there is no default, return a NULL instead.
|
|
*/
|
|
Node *
|
|
build_column_default(Relation rel, int attrno)
|
|
{
|
|
TupleDesc rd_att = rel->rd_att;
|
|
Form_pg_attribute att_tup = rd_att->attrs[attrno - 1];
|
|
Oid atttype = att_tup->atttypid;
|
|
int32 atttypmod = att_tup->atttypmod;
|
|
Node *expr = NULL;
|
|
Oid exprtype;
|
|
|
|
/*
|
|
* Scan to see if relation has a default for this column.
|
|
*/
|
|
if (rd_att->constr && rd_att->constr->num_defval > 0)
|
|
{
|
|
AttrDefault *defval = rd_att->constr->defval;
|
|
int ndef = rd_att->constr->num_defval;
|
|
|
|
while (--ndef >= 0)
|
|
{
|
|
if (attrno == defval[ndef].adnum)
|
|
{
|
|
/*
|
|
* Found it, convert string representation to node tree.
|
|
*/
|
|
expr = stringToNode(defval[ndef].adbin);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (expr == NULL)
|
|
{
|
|
/*
|
|
* No per-column default, so look for a default for the type itself.
|
|
*/
|
|
expr = get_typdefault(atttype);
|
|
}
|
|
|
|
if (expr == NULL)
|
|
return NULL; /* No default anywhere */
|
|
|
|
/*
|
|
* Make sure the value is coerced to the target column type; this will
|
|
* generally be true already, but there seem to be some corner cases
|
|
* involving domain defaults where it might not be true. This should match
|
|
* the parser's processing of non-defaulted expressions --- see
|
|
* transformAssignedExpr().
|
|
*/
|
|
exprtype = exprType(expr);
|
|
|
|
expr = coerce_to_target_type(NULL, /* no UNKNOWN params here */
|
|
expr, exprtype,
|
|
atttype, atttypmod,
|
|
COERCION_ASSIGNMENT,
|
|
COERCE_IMPLICIT_CAST,
|
|
-1);
|
|
if (expr == NULL)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATATYPE_MISMATCH),
|
|
errmsg("column \"%s\" is of type %s"
|
|
" but default expression is of type %s",
|
|
NameStr(att_tup->attname),
|
|
format_type_be(atttype),
|
|
format_type_be(exprtype)),
|
|
errhint("You will need to rewrite or cast the expression.")));
|
|
|
|
return expr;
|
|
}
|
|
|
|
|
|
/* Does VALUES RTE contain any SetToDefault items? */
|
|
static bool
|
|
searchForDefault(RangeTblEntry *rte)
|
|
{
|
|
ListCell *lc;
|
|
|
|
foreach(lc, rte->values_lists)
|
|
{
|
|
List *sublist = (List *) lfirst(lc);
|
|
ListCell *lc2;
|
|
|
|
foreach(lc2, sublist)
|
|
{
|
|
Node *col = (Node *) lfirst(lc2);
|
|
|
|
if (IsA(col, SetToDefault))
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* When processing INSERT ... VALUES with a VALUES RTE (ie, multiple VALUES
|
|
* lists), we have to replace any DEFAULT items in the VALUES lists with
|
|
* the appropriate default expressions. The other aspects of targetlist
|
|
* rewriting need be applied only to the query's targetlist proper.
|
|
*
|
|
* Note that we currently can't support subscripted or field assignment
|
|
* in the multi-VALUES case. The targetlist will contain simple Vars
|
|
* referencing the VALUES RTE, and therefore process_matched_tle() will
|
|
* reject any such attempt with "multiple assignments to same column".
|
|
*/
|
|
static void
|
|
rewriteValuesRTE(RangeTblEntry *rte, Relation target_relation, List *attrnos)
|
|
{
|
|
List *newValues;
|
|
ListCell *lc;
|
|
|
|
/*
|
|
* Rebuilding all the lists is a pretty expensive proposition in a big
|
|
* VALUES list, and it's a waste of time if there aren't any DEFAULT
|
|
* placeholders. So first scan to see if there are any.
|
|
*/
|
|
if (!searchForDefault(rte))
|
|
return; /* nothing to do */
|
|
|
|
/* Check list lengths (we can assume all the VALUES sublists are alike) */
|
|
Assert(list_length(attrnos) == list_length(linitial(rte->values_lists)));
|
|
|
|
newValues = NIL;
|
|
foreach(lc, rte->values_lists)
|
|
{
|
|
List *sublist = (List *) lfirst(lc);
|
|
List *newList = NIL;
|
|
ListCell *lc2;
|
|
ListCell *lc3;
|
|
|
|
forboth(lc2, sublist, lc3, attrnos)
|
|
{
|
|
Node *col = (Node *) lfirst(lc2);
|
|
int attrno = lfirst_int(lc3);
|
|
|
|
if (IsA(col, SetToDefault))
|
|
{
|
|
Form_pg_attribute att_tup;
|
|
Node *new_expr;
|
|
|
|
att_tup = target_relation->rd_att->attrs[attrno - 1];
|
|
|
|
if (!att_tup->attisdropped)
|
|
new_expr = build_column_default(target_relation, attrno);
|
|
else
|
|
new_expr = NULL; /* force a NULL if dropped */
|
|
|
|
/*
|
|
* If there is no default (ie, default is effectively NULL),
|
|
* we've got to explicitly set the column to NULL.
|
|
*/
|
|
if (!new_expr)
|
|
{
|
|
new_expr = (Node *) makeConst(att_tup->atttypid,
|
|
-1,
|
|
att_tup->attcollation,
|
|
att_tup->attlen,
|
|
(Datum) 0,
|
|
true, /* isnull */
|
|
att_tup->attbyval);
|
|
/* this is to catch a NOT NULL domain constraint */
|
|
new_expr = coerce_to_domain(new_expr,
|
|
InvalidOid, -1,
|
|
att_tup->atttypid,
|
|
COERCE_IMPLICIT_CAST,
|
|
-1,
|
|
false,
|
|
false);
|
|
}
|
|
newList = lappend(newList, new_expr);
|
|
}
|
|
else
|
|
newList = lappend(newList, col);
|
|
}
|
|
newValues = lappend(newValues, newList);
|
|
}
|
|
rte->values_lists = newValues;
|
|
}
|
|
|
|
|
|
/*
|
|
* rewriteTargetListUD - rewrite UPDATE/DELETE targetlist as needed
|
|
*
|
|
* This function adds a "junk" TLE that is needed to allow the executor to
|
|
* find the original row for the update or delete. When the target relation
|
|
* is a regular table, the junk TLE emits the ctid attribute of the original
|
|
* row. When the target relation is a view, there is no ctid, so we instead
|
|
* emit a whole-row Var that will contain the "old" values of the view row.
|
|
* If it's a foreign table, we let the FDW decide what to add.
|
|
*
|
|
* For UPDATE queries, this is applied after rewriteTargetListIU. The
|
|
* ordering isn't actually critical at the moment.
|
|
*/
|
|
static void
|
|
rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
|
|
Relation target_relation)
|
|
{
|
|
Var *var = NULL;
|
|
const char *attrname;
|
|
TargetEntry *tle;
|
|
|
|
if (target_relation->rd_rel->relkind == RELKIND_RELATION ||
|
|
target_relation->rd_rel->relkind == RELKIND_MATVIEW)
|
|
{
|
|
/*
|
|
* Emit CTID so that executor can find the row to update or delete.
|
|
*/
|
|
var = makeVar(parsetree->resultRelation,
|
|
SelfItemPointerAttributeNumber,
|
|
TIDOID,
|
|
-1,
|
|
InvalidOid,
|
|
0);
|
|
|
|
attrname = "ctid";
|
|
}
|
|
else if (target_relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
|
|
{
|
|
/*
|
|
* Let the foreign table's FDW add whatever junk TLEs it wants.
|
|
*/
|
|
FdwRoutine *fdwroutine;
|
|
|
|
fdwroutine = GetFdwRoutineForRelation(target_relation, false);
|
|
|
|
if (fdwroutine->AddForeignUpdateTargets != NULL)
|
|
fdwroutine->AddForeignUpdateTargets(parsetree, target_rte,
|
|
target_relation);
|
|
|
|
/*
|
|
* If we have a row-level trigger corresponding to the operation, emit
|
|
* a whole-row Var so that executor will have the "old" row to pass to
|
|
* the trigger. Alas, this misses system columns.
|
|
*/
|
|
if (target_relation->trigdesc &&
|
|
((parsetree->commandType == CMD_UPDATE &&
|
|
(target_relation->trigdesc->trig_update_after_row ||
|
|
target_relation->trigdesc->trig_update_before_row)) ||
|
|
(parsetree->commandType == CMD_DELETE &&
|
|
(target_relation->trigdesc->trig_delete_after_row ||
|
|
target_relation->trigdesc->trig_delete_before_row))))
|
|
{
|
|
var = makeWholeRowVar(target_rte,
|
|
parsetree->resultRelation,
|
|
0,
|
|
false);
|
|
|
|
attrname = "wholerow";
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* Emit whole-row Var so that executor will have the "old" view row to
|
|
* pass to the INSTEAD OF trigger.
|
|
*/
|
|
var = makeWholeRowVar(target_rte,
|
|
parsetree->resultRelation,
|
|
0,
|
|
false);
|
|
|
|
attrname = "wholerow";
|
|
}
|
|
|
|
if (var != NULL)
|
|
{
|
|
tle = makeTargetEntry((Expr *) var,
|
|
list_length(parsetree->targetList) + 1,
|
|
pstrdup(attrname),
|
|
true);
|
|
|
|
parsetree->targetList = lappend(parsetree->targetList, tle);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* matchLocks -
|
|
* match the list of locks and returns the matching rules
|
|
*/
|
|
static List *
|
|
matchLocks(CmdType event,
|
|
RuleLock *rulelocks,
|
|
int varno,
|
|
Query *parsetree,
|
|
bool *hasUpdate)
|
|
{
|
|
List *matching_locks = NIL;
|
|
int nlocks;
|
|
int i;
|
|
|
|
if (rulelocks == NULL)
|
|
return NIL;
|
|
|
|
if (parsetree->commandType != CMD_SELECT)
|
|
{
|
|
if (parsetree->resultRelation != varno)
|
|
return NIL;
|
|
}
|
|
|
|
nlocks = rulelocks->numLocks;
|
|
|
|
for (i = 0; i < nlocks; i++)
|
|
{
|
|
RewriteRule *oneLock = rulelocks->rules[i];
|
|
|
|
if (oneLock->event == CMD_UPDATE)
|
|
*hasUpdate = true;
|
|
|
|
/*
|
|
* Suppress ON INSERT/UPDATE/DELETE rules that are disabled or
|
|
* configured to not fire during the current sessions replication
|
|
* role. ON SELECT rules will always be applied in order to keep views
|
|
* working even in LOCAL or REPLICA role.
|
|
*/
|
|
if (oneLock->event != CMD_SELECT)
|
|
{
|
|
if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
|
|
{
|
|
if (oneLock->enabled == RULE_FIRES_ON_ORIGIN ||
|
|
oneLock->enabled == RULE_DISABLED)
|
|
continue;
|
|
}
|
|
else /* ORIGIN or LOCAL ROLE */
|
|
{
|
|
if (oneLock->enabled == RULE_FIRES_ON_REPLICA ||
|
|
oneLock->enabled == RULE_DISABLED)
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (oneLock->event == event)
|
|
{
|
|
if (parsetree->commandType != CMD_SELECT ||
|
|
rangeTableEntry_used((Node *) parsetree, varno, 0))
|
|
matching_locks = lappend(matching_locks, oneLock);
|
|
}
|
|
}
|
|
|
|
return matching_locks;
|
|
}
|
|
|
|
|
|
/*
|
|
* ApplyRetrieveRule - expand an ON SELECT rule
|
|
*/
|
|
static Query *
|
|
ApplyRetrieveRule(Query *parsetree,
|
|
RewriteRule *rule,
|
|
int rt_index,
|
|
Relation relation,
|
|
List *activeRIRs,
|
|
bool forUpdatePushedDown)
|
|
{
|
|
Query *rule_action;
|
|
RangeTblEntry *rte,
|
|
*subrte;
|
|
RowMarkClause *rc;
|
|
|
|
if (list_length(rule->actions) != 1)
|
|
elog(ERROR, "expected just one rule action");
|
|
if (rule->qual != NULL)
|
|
elog(ERROR, "cannot handle qualified ON SELECT rule");
|
|
|
|
if (rt_index == parsetree->resultRelation)
|
|
{
|
|
/*
|
|
* We have a view as the result relation of the query, and it wasn't
|
|
* rewritten by any rule. This case is supported if there is an
|
|
* INSTEAD OF trigger that will trap attempts to insert/update/delete
|
|
* view rows. The executor will check that; for the moment just plow
|
|
* ahead. We have two cases:
|
|
*
|
|
* For INSERT, we needn't do anything. The unmodified RTE will serve
|
|
* fine as the result relation.
|
|
*
|
|
* For UPDATE/DELETE, we need to expand the view so as to have source
|
|
* data for the operation. But we also need an unmodified RTE to
|
|
* serve as the target. So, copy the RTE and add the copy to the
|
|
* rangetable. Note that the copy does not get added to the jointree.
|
|
* Also note that there's a hack in fireRIRrules to avoid calling this
|
|
* function again when it arrives at the copied RTE.
|
|
*/
|
|
if (parsetree->commandType == CMD_INSERT)
|
|
return parsetree;
|
|
else if (parsetree->commandType == CMD_UPDATE ||
|
|
parsetree->commandType == CMD_DELETE)
|
|
{
|
|
RangeTblEntry *newrte;
|
|
|
|
rte = rt_fetch(rt_index, parsetree->rtable);
|
|
newrte = copyObject(rte);
|
|
parsetree->rtable = lappend(parsetree->rtable, newrte);
|
|
parsetree->resultRelation = list_length(parsetree->rtable);
|
|
|
|
/*
|
|
* There's no need to do permissions checks twice, so wipe out the
|
|
* permissions info for the original RTE (we prefer to keep the
|
|
* bits set on the result RTE).
|
|
*/
|
|
rte->requiredPerms = 0;
|
|
rte->checkAsUser = InvalidOid;
|
|
rte->selectedCols = NULL;
|
|
rte->insertedCols = NULL;
|
|
rte->updatedCols = NULL;
|
|
|
|
/*
|
|
* For the most part, Vars referencing the view should remain as
|
|
* they are, meaning that they implicitly represent OLD values.
|
|
* But in the RETURNING list if any, we want such Vars to
|
|
* represent NEW values, so change them to reference the new RTE.
|
|
*
|
|
* Since ChangeVarNodes scribbles on the tree in-place, copy the
|
|
* RETURNING list first for safety.
|
|
*/
|
|
parsetree->returningList = copyObject(parsetree->returningList);
|
|
ChangeVarNodes((Node *) parsetree->returningList, rt_index,
|
|
parsetree->resultRelation, 0);
|
|
|
|
/* Now, continue with expanding the original view RTE */
|
|
}
|
|
else
|
|
elog(ERROR, "unrecognized commandType: %d",
|
|
(int) parsetree->commandType);
|
|
}
|
|
|
|
/*
|
|
* If FOR [KEY] UPDATE/SHARE of view, be sure we get right initial lock on
|
|
* the relations it references.
|
|
*/
|
|
rc = get_parse_rowmark(parsetree, rt_index);
|
|
forUpdatePushedDown |= (rc != NULL);
|
|
|
|
/*
|
|
* Make a modifiable copy of the view query, and acquire needed locks on
|
|
* the relations it mentions.
|
|
*/
|
|
rule_action = copyObject(linitial(rule->actions));
|
|
|
|
AcquireRewriteLocks(rule_action, true, forUpdatePushedDown);
|
|
|
|
/*
|
|
* Recursively expand any view references inside the view.
|
|
*/
|
|
rule_action = fireRIRrules(rule_action, activeRIRs, forUpdatePushedDown);
|
|
|
|
/*
|
|
* Now, plug the view query in as a subselect, replacing the relation's
|
|
* original RTE.
|
|
*/
|
|
rte = rt_fetch(rt_index, parsetree->rtable);
|
|
|
|
rte->rtekind = RTE_SUBQUERY;
|
|
rte->relid = InvalidOid;
|
|
rte->security_barrier = RelationIsSecurityView(relation);
|
|
rte->subquery = rule_action;
|
|
rte->inh = false; /* must not be set for a subquery */
|
|
|
|
/*
|
|
* We move the view's permission check data down to its rangetable. The
|
|
* checks will actually be done against the OLD entry therein.
|
|
*/
|
|
subrte = rt_fetch(PRS2_OLD_VARNO, rule_action->rtable);
|
|
Assert(subrte->relid == relation->rd_id);
|
|
subrte->requiredPerms = rte->requiredPerms;
|
|
subrte->checkAsUser = rte->checkAsUser;
|
|
subrte->selectedCols = rte->selectedCols;
|
|
subrte->insertedCols = rte->insertedCols;
|
|
subrte->updatedCols = rte->updatedCols;
|
|
|
|
rte->requiredPerms = 0; /* no permission check on subquery itself */
|
|
rte->checkAsUser = InvalidOid;
|
|
rte->selectedCols = NULL;
|
|
rte->insertedCols = NULL;
|
|
rte->updatedCols = NULL;
|
|
|
|
/*
|
|
* If FOR [KEY] UPDATE/SHARE of view, mark all the contained tables as
|
|
* implicit FOR [KEY] UPDATE/SHARE, the same as the parser would have done
|
|
* if the view's subquery had been written out explicitly.
|
|
*
|
|
* Note: we don't consider forUpdatePushedDown here; such marks will be
|
|
* made by recursing from the upper level in markQueryForLocking.
|
|
*/
|
|
if (rc != NULL)
|
|
markQueryForLocking(rule_action, (Node *) rule_action->jointree,
|
|
rc->strength, rc->waitPolicy, true);
|
|
|
|
return parsetree;
|
|
}
|
|
|
|
/*
|
|
* Recursively mark all relations used by a view as FOR [KEY] UPDATE/SHARE.
|
|
*
|
|
* This may generate an invalid query, eg if some sub-query uses an
|
|
* aggregate. We leave it to the planner to detect that.
|
|
*
|
|
* NB: this must agree with the parser's transformLockingClause() routine.
|
|
* However, unlike the parser we have to be careful not to mark a view's
|
|
* OLD and NEW rels for updating. The best way to handle that seems to be
|
|
* to scan the jointree to determine which rels are used.
|
|
*/
|
|
static void
|
|
markQueryForLocking(Query *qry, Node *jtnode,
|
|
LockClauseStrength strength, LockWaitPolicy waitPolicy,
|
|
bool pushedDown)
|
|
{
|
|
if (jtnode == NULL)
|
|
return;
|
|
if (IsA(jtnode, RangeTblRef))
|
|
{
|
|
int rti = ((RangeTblRef *) jtnode)->rtindex;
|
|
RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
|
|
|
|
if (rte->rtekind == RTE_RELATION)
|
|
{
|
|
applyLockingClause(qry, rti, strength, waitPolicy, pushedDown);
|
|
rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
|
|
}
|
|
else if (rte->rtekind == RTE_SUBQUERY)
|
|
{
|
|
applyLockingClause(qry, rti, strength, waitPolicy, pushedDown);
|
|
/* FOR UPDATE/SHARE of subquery is propagated to subquery's rels */
|
|
markQueryForLocking(rte->subquery, (Node *) rte->subquery->jointree,
|
|
strength, waitPolicy, true);
|
|
}
|
|
/* other RTE types are unaffected by FOR UPDATE */
|
|
}
|
|
else if (IsA(jtnode, FromExpr))
|
|
{
|
|
FromExpr *f = (FromExpr *) jtnode;
|
|
ListCell *l;
|
|
|
|
foreach(l, f->fromlist)
|
|
markQueryForLocking(qry, lfirst(l), strength, waitPolicy, pushedDown);
|
|
}
|
|
else if (IsA(jtnode, JoinExpr))
|
|
{
|
|
JoinExpr *j = (JoinExpr *) jtnode;
|
|
|
|
markQueryForLocking(qry, j->larg, strength, waitPolicy, pushedDown);
|
|
markQueryForLocking(qry, j->rarg, strength, waitPolicy, pushedDown);
|
|
}
|
|
else
|
|
elog(ERROR, "unrecognized node type: %d",
|
|
(int) nodeTag(jtnode));
|
|
}
|
|
|
|
|
|
/*
|
|
* fireRIRonSubLink -
|
|
* Apply fireRIRrules() to each SubLink (subselect in expression) found
|
|
* in the given tree.
|
|
*
|
|
* NOTE: although this has the form of a walker, we cheat and modify the
|
|
* SubLink nodes in-place. It is caller's responsibility to ensure that
|
|
* no unwanted side-effects occur!
|
|
*
|
|
* This is unlike most of the other routines that recurse into subselects,
|
|
* because we must take control at the SubLink node in order to replace
|
|
* the SubLink's subselect link with the possibly-rewritten subquery.
|
|
*/
|
|
static bool
|
|
fireRIRonSubLink(Node *node, List *activeRIRs)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, SubLink))
|
|
{
|
|
SubLink *sub = (SubLink *) node;
|
|
|
|
/* Do what we came for */
|
|
sub->subselect = (Node *) fireRIRrules((Query *) sub->subselect,
|
|
activeRIRs, false);
|
|
/* Fall through to process lefthand args of SubLink */
|
|
}
|
|
|
|
/*
|
|
* Do NOT recurse into Query nodes, because fireRIRrules already processed
|
|
* subselects of subselects for us.
|
|
*/
|
|
return expression_tree_walker(node, fireRIRonSubLink,
|
|
(void *) activeRIRs);
|
|
}
|
|
|
|
|
|
/*
|
|
* fireRIRrules -
|
|
* Apply all RIR rules on each rangetable entry in a query
|
|
*/
|
|
static Query *
|
|
fireRIRrules(Query *parsetree, List *activeRIRs, bool forUpdatePushedDown)
|
|
{
|
|
int origResultRelation = parsetree->resultRelation;
|
|
int rt_index;
|
|
ListCell *lc;
|
|
|
|
/*
|
|
* don't try to convert this into a foreach loop, because rtable list can
|
|
* get changed each time through...
|
|
*/
|
|
rt_index = 0;
|
|
while (rt_index < list_length(parsetree->rtable))
|
|
{
|
|
RangeTblEntry *rte;
|
|
Relation rel;
|
|
List *locks;
|
|
RuleLock *rules;
|
|
RewriteRule *rule;
|
|
int i;
|
|
|
|
++rt_index;
|
|
|
|
rte = rt_fetch(rt_index, parsetree->rtable);
|
|
|
|
/*
|
|
* A subquery RTE can't have associated rules, so there's nothing to
|
|
* do to this level of the query, but we must recurse into the
|
|
* subquery to expand any rule references in it.
|
|
*/
|
|
if (rte->rtekind == RTE_SUBQUERY)
|
|
{
|
|
rte->subquery = fireRIRrules(rte->subquery, activeRIRs,
|
|
(forUpdatePushedDown ||
|
|
get_parse_rowmark(parsetree, rt_index) != NULL));
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Joins and other non-relation RTEs can be ignored completely.
|
|
*/
|
|
if (rte->rtekind != RTE_RELATION)
|
|
continue;
|
|
|
|
/*
|
|
* Always ignore RIR rules for materialized views referenced in
|
|
* queries. (This does not prevent refreshing MVs, since they aren't
|
|
* referenced in their own query definitions.)
|
|
*
|
|
* Note: in the future we might want to allow MVs to be conditionally
|
|
* expanded as if they were regular views, if they are not scannable.
|
|
* In that case this test would need to be postponed till after we've
|
|
* opened the rel, so that we could check its state.
|
|
*/
|
|
if (rte->relkind == RELKIND_MATVIEW)
|
|
continue;
|
|
|
|
/*
|
|
* If the table is not referenced in the query, then we ignore it.
|
|
* This prevents infinite expansion loop due to new rtable entries
|
|
* inserted by expansion of a rule. A table is referenced if it is
|
|
* part of the join set (a source table), or is referenced by any Var
|
|
* nodes, or is the result table.
|
|
*/
|
|
if (rt_index != parsetree->resultRelation &&
|
|
!rangeTableEntry_used((Node *) parsetree, rt_index, 0))
|
|
continue;
|
|
|
|
/*
|
|
* Also, if this is a new result relation introduced by
|
|
* ApplyRetrieveRule, we don't want to do anything more with it.
|
|
*/
|
|
if (rt_index == parsetree->resultRelation &&
|
|
rt_index != origResultRelation)
|
|
continue;
|
|
|
|
/*
|
|
* We can use NoLock here since either the parser or
|
|
* AcquireRewriteLocks should have locked the rel already.
|
|
*/
|
|
rel = heap_open(rte->relid, NoLock);
|
|
|
|
/*
|
|
* Collect the RIR rules that we must apply
|
|
*/
|
|
rules = rel->rd_rules;
|
|
if (rules != NULL)
|
|
{
|
|
locks = NIL;
|
|
for (i = 0; i < rules->numLocks; i++)
|
|
{
|
|
rule = rules->rules[i];
|
|
if (rule->event != CMD_SELECT)
|
|
continue;
|
|
|
|
locks = lappend(locks, rule);
|
|
}
|
|
|
|
/*
|
|
* If we found any, apply them --- but first check for recursion!
|
|
*/
|
|
if (locks != NIL)
|
|
{
|
|
ListCell *l;
|
|
|
|
if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
|
|
errmsg("infinite recursion detected in rules for relation \"%s\"",
|
|
RelationGetRelationName(rel))));
|
|
activeRIRs = lcons_oid(RelationGetRelid(rel), activeRIRs);
|
|
|
|
foreach(l, locks)
|
|
{
|
|
rule = lfirst(l);
|
|
|
|
parsetree = ApplyRetrieveRule(parsetree,
|
|
rule,
|
|
rt_index,
|
|
rel,
|
|
activeRIRs,
|
|
forUpdatePushedDown);
|
|
}
|
|
|
|
activeRIRs = list_delete_first(activeRIRs);
|
|
}
|
|
}
|
|
|
|
heap_close(rel, NoLock);
|
|
}
|
|
|
|
/* Recurse into subqueries in WITH */
|
|
foreach(lc, parsetree->cteList)
|
|
{
|
|
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
|
|
|
|
cte->ctequery = (Node *)
|
|
fireRIRrules((Query *) cte->ctequery, activeRIRs, false);
|
|
}
|
|
|
|
/*
|
|
* Recurse into sublink subqueries, too. But we already did the ones in
|
|
* the rtable and cteList.
|
|
*/
|
|
if (parsetree->hasSubLinks)
|
|
query_tree_walker(parsetree, fireRIRonSubLink, (void *) activeRIRs,
|
|
QTW_IGNORE_RC_SUBQUERIES);
|
|
|
|
/*
|
|
* Apply any row level security policies. We do this last because it
|
|
* requires special recursion detection if the new quals have sublink
|
|
* subqueries, and if we did it in the loop above query_tree_walker would
|
|
* then recurse into those quals a second time.
|
|
*/
|
|
rt_index = 0;
|
|
foreach(lc, parsetree->rtable)
|
|
{
|
|
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
|
|
Relation rel;
|
|
List *securityQuals;
|
|
List *withCheckOptions;
|
|
bool hasRowSecurity;
|
|
bool hasSubLinks;
|
|
|
|
++rt_index;
|
|
|
|
/* Only normal relations can have RLS policies */
|
|
if (rte->rtekind != RTE_RELATION ||
|
|
rte->relkind != RELKIND_RELATION)
|
|
continue;
|
|
|
|
rel = heap_open(rte->relid, NoLock);
|
|
|
|
/*
|
|
* Fetch any new security quals that must be applied to this RTE.
|
|
*/
|
|
get_row_security_policies(parsetree, parsetree->commandType, rte,
|
|
rt_index, &securityQuals, &withCheckOptions,
|
|
&hasRowSecurity, &hasSubLinks);
|
|
|
|
if (securityQuals != NIL || withCheckOptions != NIL)
|
|
{
|
|
if (hasSubLinks)
|
|
{
|
|
/*
|
|
* Recursively process the new quals, checking for infinite
|
|
* recursion.
|
|
*/
|
|
if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
|
|
errmsg("infinite recursion detected in policy for relation \"%s\"",
|
|
RelationGetRelationName(rel))));
|
|
|
|
activeRIRs = lcons_oid(RelationGetRelid(rel), activeRIRs);
|
|
|
|
expression_tree_walker((Node *) securityQuals,
|
|
fireRIRonSubLink, (void *) activeRIRs);
|
|
|
|
expression_tree_walker((Node *) withCheckOptions,
|
|
fireRIRonSubLink, (void *) activeRIRs);
|
|
|
|
activeRIRs = list_delete_first(activeRIRs);
|
|
}
|
|
|
|
/*
|
|
* Add the new security quals to the start of the RTE's list so
|
|
* that they get applied before any existing security quals (which
|
|
* might have come from a user-written security barrier view, and
|
|
* might contain malicious code).
|
|
*/
|
|
rte->securityQuals = list_concat(securityQuals,
|
|
rte->securityQuals);
|
|
|
|
parsetree->withCheckOptions = list_concat(withCheckOptions,
|
|
parsetree->withCheckOptions);
|
|
}
|
|
|
|
/*
|
|
* Make sure the query is marked correctly if row level security
|
|
* applies, or if the new quals had sublinks.
|
|
*/
|
|
if (hasRowSecurity)
|
|
parsetree->hasRowSecurity = true;
|
|
if (hasSubLinks)
|
|
parsetree->hasSubLinks = true;
|
|
|
|
heap_close(rel, NoLock);
|
|
}
|
|
|
|
return parsetree;
|
|
}
|
|
|
|
|
|
/*
|
|
* Modify the given query by adding 'AND rule_qual IS NOT TRUE' to its
|
|
* qualification. This is used to generate suitable "else clauses" for
|
|
* conditional INSTEAD rules. (Unfortunately we must use "x IS NOT TRUE",
|
|
* not just "NOT x" which the planner is much smarter about, else we will
|
|
* do the wrong thing when the qual evaluates to NULL.)
|
|
*
|
|
* The rule_qual may contain references to OLD or NEW. OLD references are
|
|
* replaced by references to the specified rt_index (the relation that the
|
|
* rule applies to). NEW references are only possible for INSERT and UPDATE
|
|
* queries on the relation itself, and so they should be replaced by copies
|
|
* of the related entries in the query's own targetlist.
|
|
*/
|
|
static Query *
|
|
CopyAndAddInvertedQual(Query *parsetree,
|
|
Node *rule_qual,
|
|
int rt_index,
|
|
CmdType event)
|
|
{
|
|
/* Don't scribble on the passed qual (it's in the relcache!) */
|
|
Node *new_qual = (Node *) copyObject(rule_qual);
|
|
acquireLocksOnSubLinks_context context;
|
|
|
|
context.for_execute = true;
|
|
|
|
/*
|
|
* In case there are subqueries in the qual, acquire necessary locks and
|
|
* fix any deleted JOIN RTE entries. (This is somewhat redundant with
|
|
* rewriteRuleAction, but not entirely ... consider restructuring so that
|
|
* we only need to process the qual this way once.)
|
|
*/
|
|
(void) acquireLocksOnSubLinks(new_qual, &context);
|
|
|
|
/* Fix references to OLD */
|
|
ChangeVarNodes(new_qual, PRS2_OLD_VARNO, rt_index, 0);
|
|
/* Fix references to NEW */
|
|
if (event == CMD_INSERT || event == CMD_UPDATE)
|
|
new_qual = ReplaceVarsFromTargetList(new_qual,
|
|
PRS2_NEW_VARNO,
|
|
0,
|
|
rt_fetch(rt_index,
|
|
parsetree->rtable),
|
|
parsetree->targetList,
|
|
(event == CMD_UPDATE) ?
|
|
REPLACEVARS_CHANGE_VARNO :
|
|
REPLACEVARS_SUBSTITUTE_NULL,
|
|
rt_index,
|
|
&parsetree->hasSubLinks);
|
|
/* And attach the fixed qual */
|
|
AddInvertedQual(parsetree, new_qual);
|
|
|
|
return parsetree;
|
|
}
|
|
|
|
|
|
/*
|
|
* fireRules -
|
|
* Iterate through rule locks applying rules.
|
|
*
|
|
* Input arguments:
|
|
* parsetree - original query
|
|
* rt_index - RT index of result relation in original query
|
|
* event - type of rule event
|
|
* locks - list of rules to fire
|
|
* Output arguments:
|
|
* *instead_flag - set TRUE if any unqualified INSTEAD rule is found
|
|
* (must be initialized to FALSE)
|
|
* *returning_flag - set TRUE if we rewrite RETURNING clause in any rule
|
|
* (must be initialized to FALSE)
|
|
* *qual_product - filled with modified original query if any qualified
|
|
* INSTEAD rule is found (must be initialized to NULL)
|
|
* Return value:
|
|
* list of rule actions adjusted for use with this query
|
|
*
|
|
* Qualified INSTEAD rules generate their action with the qualification
|
|
* condition added. They also generate a modified version of the original
|
|
* query with the negated qualification added, so that it will run only for
|
|
* rows that the qualified action doesn't act on. (If there are multiple
|
|
* qualified INSTEAD rules, we AND all the negated quals onto a single
|
|
* modified original query.) We won't execute the original, unmodified
|
|
* query if we find either qualified or unqualified INSTEAD rules. If
|
|
* we find both, the modified original query is discarded too.
|
|
*/
|
|
static List *
|
|
fireRules(Query *parsetree,
|
|
int rt_index,
|
|
CmdType event,
|
|
List *locks,
|
|
bool *instead_flag,
|
|
bool *returning_flag,
|
|
Query **qual_product)
|
|
{
|
|
List *results = NIL;
|
|
ListCell *l;
|
|
|
|
foreach(l, locks)
|
|
{
|
|
RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
|
|
Node *event_qual = rule_lock->qual;
|
|
List *actions = rule_lock->actions;
|
|
QuerySource qsrc;
|
|
ListCell *r;
|
|
|
|
/* Determine correct QuerySource value for actions */
|
|
if (rule_lock->isInstead)
|
|
{
|
|
if (event_qual != NULL)
|
|
qsrc = QSRC_QUAL_INSTEAD_RULE;
|
|
else
|
|
{
|
|
qsrc = QSRC_INSTEAD_RULE;
|
|
*instead_flag = true; /* report unqualified INSTEAD */
|
|
}
|
|
}
|
|
else
|
|
qsrc = QSRC_NON_INSTEAD_RULE;
|
|
|
|
if (qsrc == QSRC_QUAL_INSTEAD_RULE)
|
|
{
|
|
/*
|
|
* If there are INSTEAD rules with qualifications, the original
|
|
* query is still performed. But all the negated rule
|
|
* qualifications of the INSTEAD rules are added so it does its
|
|
* actions only in cases where the rule quals of all INSTEAD rules
|
|
* are false. Think of it as the default action in a case. We save
|
|
* this in *qual_product so RewriteQuery() can add it to the query
|
|
* list after we mangled it up enough.
|
|
*
|
|
* If we have already found an unqualified INSTEAD rule, then
|
|
* *qual_product won't be used, so don't bother building it.
|
|
*/
|
|
if (!*instead_flag)
|
|
{
|
|
if (*qual_product == NULL)
|
|
*qual_product = copyObject(parsetree);
|
|
*qual_product = CopyAndAddInvertedQual(*qual_product,
|
|
event_qual,
|
|
rt_index,
|
|
event);
|
|
}
|
|
}
|
|
|
|
/* Now process the rule's actions and add them to the result list */
|
|
foreach(r, actions)
|
|
{
|
|
Query *rule_action = lfirst(r);
|
|
|
|
if (rule_action->commandType == CMD_NOTHING)
|
|
continue;
|
|
|
|
rule_action = rewriteRuleAction(parsetree, rule_action,
|
|
event_qual, rt_index, event,
|
|
returning_flag);
|
|
|
|
rule_action->querySource = qsrc;
|
|
rule_action->canSetTag = false; /* might change later */
|
|
|
|
results = lappend(results, rule_action);
|
|
}
|
|
}
|
|
|
|
return results;
|
|
}
|
|
|
|
|
|
/*
|
|
* get_view_query - get the Query from a view's _RETURN rule.
|
|
*
|
|
* Caller should have verified that the relation is a view, and therefore
|
|
* we should find an ON SELECT action.
|
|
*/
|
|
Query *
|
|
get_view_query(Relation view)
|
|
{
|
|
int i;
|
|
|
|
Assert(view->rd_rel->relkind == RELKIND_VIEW);
|
|
|
|
for (i = 0; i < view->rd_rules->numLocks; i++)
|
|
{
|
|
RewriteRule *rule = view->rd_rules->rules[i];
|
|
|
|
if (rule->event == CMD_SELECT)
|
|
{
|
|
/* A _RETURN rule should have only one action */
|
|
if (list_length(rule->actions) != 1)
|
|
elog(ERROR, "invalid _RETURN rule action specification");
|
|
|
|
return (Query *) linitial(rule->actions);
|
|
}
|
|
}
|
|
|
|
elog(ERROR, "failed to find _RETURN rule for view");
|
|
return NULL; /* keep compiler quiet */
|
|
}
|
|
|
|
|
|
/*
|
|
* view_has_instead_trigger - does view have an INSTEAD OF trigger for event?
|
|
*
|
|
* If it does, we don't want to treat it as auto-updatable. This test can't
|
|
* be folded into view_query_is_auto_updatable because it's not an error
|
|
* condition.
|
|
*/
|
|
static bool
|
|
view_has_instead_trigger(Relation view, CmdType event)
|
|
{
|
|
TriggerDesc *trigDesc = view->trigdesc;
|
|
|
|
switch (event)
|
|
{
|
|
case CMD_INSERT:
|
|
if (trigDesc && trigDesc->trig_insert_instead_row)
|
|
return true;
|
|
break;
|
|
case CMD_UPDATE:
|
|
if (trigDesc && trigDesc->trig_update_instead_row)
|
|
return true;
|
|
break;
|
|
case CMD_DELETE:
|
|
if (trigDesc && trigDesc->trig_delete_instead_row)
|
|
return true;
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized CmdType: %d", (int) event);
|
|
break;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
|
|
/*
|
|
* view_col_is_auto_updatable - test whether the specified column of a view
|
|
* is auto-updatable. Returns NULL (if the column can be updated) or a message
|
|
* string giving the reason that it cannot be.
|
|
*
|
|
* Note that the checks performed here are local to this view. We do not check
|
|
* whether the referenced column of the underlying base relation is updatable.
|
|
*/
|
|
static const char *
|
|
view_col_is_auto_updatable(RangeTblRef *rtr, TargetEntry *tle)
|
|
{
|
|
Var *var = (Var *) tle->expr;
|
|
|
|
/*
|
|
* For now, the only updatable columns we support are those that are Vars
|
|
* referring to user columns of the underlying base relation.
|
|
*
|
|
* The view targetlist may contain resjunk columns (e.g., a view defined
|
|
* like "SELECT * FROM t ORDER BY a+b" is auto-updatable) but such columns
|
|
* are not auto-updatable, and in fact should never appear in the outer
|
|
* query's targetlist.
|
|
*/
|
|
if (tle->resjunk)
|
|
return gettext_noop("Junk view columns are not updatable.");
|
|
|
|
if (!IsA(var, Var) ||
|
|
var->varno != rtr->rtindex ||
|
|
var->varlevelsup != 0)
|
|
return gettext_noop("View columns that are not columns of their base relation are not updatable.");
|
|
|
|
if (var->varattno < 0)
|
|
return gettext_noop("View columns that refer to system columns are not updatable.");
|
|
|
|
if (var->varattno == 0)
|
|
return gettext_noop("View columns that return whole-row references are not updatable.");
|
|
|
|
return NULL; /* the view column is updatable */
|
|
}
|
|
|
|
|
|
/*
|
|
* view_query_is_auto_updatable - test whether the specified view definition
|
|
* represents an auto-updatable view. Returns NULL (if the view can be updated)
|
|
* or a message string giving the reason that it cannot be.
|
|
*
|
|
* If check_cols is true, the view is required to have at least one updatable
|
|
* column (necessary for INSERT/UPDATE). Otherwise the view's columns are not
|
|
* checked for updatability. See also view_cols_are_auto_updatable.
|
|
*
|
|
* Note that the checks performed here are only based on the view definition.
|
|
* We do not check whether any base relations referred to by the view are
|
|
* updatable.
|
|
*/
|
|
const char *
|
|
view_query_is_auto_updatable(Query *viewquery, bool check_cols)
|
|
{
|
|
RangeTblRef *rtr;
|
|
RangeTblEntry *base_rte;
|
|
|
|
/*----------
|
|
* Check if the view is simply updatable. According to SQL-92 this means:
|
|
* - No DISTINCT clause.
|
|
* - Each TLE is a column reference, and each column appears at most once.
|
|
* - FROM contains exactly one base relation.
|
|
* - No GROUP BY or HAVING clauses.
|
|
* - No set operations (UNION, INTERSECT or EXCEPT).
|
|
* - No sub-queries in the WHERE clause that reference the target table.
|
|
*
|
|
* We ignore that last restriction since it would be complex to enforce
|
|
* and there isn't any actual benefit to disallowing sub-queries. (The
|
|
* semantic issues that the standard is presumably concerned about don't
|
|
* arise in Postgres, since any such sub-query will not see any updates
|
|
* executed by the outer query anyway, thanks to MVCC snapshotting.)
|
|
*
|
|
* We also relax the second restriction by supporting part of SQL:1999
|
|
* feature T111, which allows for a mix of updatable and non-updatable
|
|
* columns, provided that an INSERT or UPDATE doesn't attempt to assign to
|
|
* a non-updatable column.
|
|
*
|
|
* In addition we impose these constraints, involving features that are
|
|
* not part of SQL-92:
|
|
* - No CTEs (WITH clauses).
|
|
* - No OFFSET or LIMIT clauses (this matches a SQL:2008 restriction).
|
|
* - No system columns (including whole-row references) in the tlist.
|
|
* - No window functions in the tlist.
|
|
* - No set-returning functions in the tlist.
|
|
*
|
|
* Note that we do these checks without recursively expanding the view.
|
|
* If the base relation is a view, we'll recursively deal with it later.
|
|
*----------
|
|
*/
|
|
if (viewquery->distinctClause != NIL)
|
|
return gettext_noop("Views containing DISTINCT are not automatically updatable.");
|
|
|
|
if (viewquery->groupClause != NIL || viewquery->groupingSets)
|
|
return gettext_noop("Views containing GROUP BY are not automatically updatable.");
|
|
|
|
if (viewquery->havingQual != NULL)
|
|
return gettext_noop("Views containing HAVING are not automatically updatable.");
|
|
|
|
if (viewquery->setOperations != NULL)
|
|
return gettext_noop("Views containing UNION, INTERSECT, or EXCEPT are not automatically updatable.");
|
|
|
|
if (viewquery->cteList != NIL)
|
|
return gettext_noop("Views containing WITH are not automatically updatable.");
|
|
|
|
if (viewquery->limitOffset != NULL || viewquery->limitCount != NULL)
|
|
return gettext_noop("Views containing LIMIT or OFFSET are not automatically updatable.");
|
|
|
|
/*
|
|
* We must not allow window functions or set returning functions in the
|
|
* targetlist. Otherwise we might end up inserting them into the quals of
|
|
* the main query. We must also check for aggregates in the targetlist in
|
|
* case they appear without a GROUP BY.
|
|
*
|
|
* These restrictions ensure that each row of the view corresponds to a
|
|
* unique row in the underlying base relation.
|
|
*/
|
|
if (viewquery->hasAggs)
|
|
return gettext_noop("Views that return aggregate functions are not automatically updatable.");
|
|
|
|
if (viewquery->hasWindowFuncs)
|
|
return gettext_noop("Views that return window functions are not automatically updatable.");
|
|
|
|
if (expression_returns_set((Node *) viewquery->targetList))
|
|
return gettext_noop("Views that return set-returning functions are not automatically updatable.");
|
|
|
|
/*
|
|
* The view query should select from a single base relation, which must be
|
|
* a table or another view.
|
|
*/
|
|
if (list_length(viewquery->jointree->fromlist) != 1)
|
|
return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
|
|
|
|
rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
|
|
if (!IsA(rtr, RangeTblRef))
|
|
return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
|
|
|
|
base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
|
|
if (base_rte->rtekind != RTE_RELATION ||
|
|
(base_rte->relkind != RELKIND_RELATION &&
|
|
base_rte->relkind != RELKIND_FOREIGN_TABLE &&
|
|
base_rte->relkind != RELKIND_VIEW))
|
|
return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
|
|
|
|
if (base_rte->tablesample)
|
|
return gettext_noop("Views containing TABLESAMPLE are not automatically updatable.");
|
|
|
|
/*
|
|
* Check that the view has at least one updatable column. This is required
|
|
* for INSERT/UPDATE but not for DELETE.
|
|
*/
|
|
if (check_cols)
|
|
{
|
|
ListCell *cell;
|
|
bool found;
|
|
|
|
found = false;
|
|
foreach(cell, viewquery->targetList)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) lfirst(cell);
|
|
|
|
if (view_col_is_auto_updatable(rtr, tle) == NULL)
|
|
{
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!found)
|
|
return gettext_noop("Views that have no updatable columns are not automatically updatable.");
|
|
}
|
|
|
|
return NULL; /* the view is updatable */
|
|
}
|
|
|
|
|
|
/*
|
|
* view_cols_are_auto_updatable - test whether all of the required columns of
|
|
* an auto-updatable view are actually updatable. Returns NULL (if all the
|
|
* required columns can be updated) or a message string giving the reason that
|
|
* they cannot be.
|
|
*
|
|
* This should be used for INSERT/UPDATE to ensure that we don't attempt to
|
|
* assign to any non-updatable columns.
|
|
*
|
|
* Additionally it may be used to retrieve the set of updatable columns in the
|
|
* view, or if one or more of the required columns is not updatable, the name
|
|
* of the first offending non-updatable column.
|
|
*
|
|
* The caller must have already verified that this is an auto-updatable view
|
|
* using view_query_is_auto_updatable.
|
|
*
|
|
* Note that the checks performed here are only based on the view definition.
|
|
* We do not check whether the referenced columns of the base relation are
|
|
* updatable.
|
|
*/
|
|
static const char *
|
|
view_cols_are_auto_updatable(Query *viewquery,
|
|
Bitmapset *required_cols,
|
|
Bitmapset **updatable_cols,
|
|
char **non_updatable_col)
|
|
{
|
|
RangeTblRef *rtr;
|
|
AttrNumber col;
|
|
ListCell *cell;
|
|
|
|
/*
|
|
* The caller should have verified that this view is auto-updatable and so
|
|
* there should be a single base relation.
|
|
*/
|
|
Assert(list_length(viewquery->jointree->fromlist) == 1);
|
|
rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
|
|
Assert(IsA(rtr, RangeTblRef));
|
|
|
|
/* Initialize the optional return values */
|
|
if (updatable_cols != NULL)
|
|
*updatable_cols = NULL;
|
|
if (non_updatable_col != NULL)
|
|
*non_updatable_col = NULL;
|
|
|
|
/* Test each view column for updatability */
|
|
col = -FirstLowInvalidHeapAttributeNumber;
|
|
foreach(cell, viewquery->targetList)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) lfirst(cell);
|
|
const char *col_update_detail;
|
|
|
|
col++;
|
|
col_update_detail = view_col_is_auto_updatable(rtr, tle);
|
|
|
|
if (col_update_detail == NULL)
|
|
{
|
|
/* The column is updatable */
|
|
if (updatable_cols != NULL)
|
|
*updatable_cols = bms_add_member(*updatable_cols, col);
|
|
}
|
|
else if (bms_is_member(col, required_cols))
|
|
{
|
|
/* The required column is not updatable */
|
|
if (non_updatable_col != NULL)
|
|
*non_updatable_col = tle->resname;
|
|
return col_update_detail;
|
|
}
|
|
}
|
|
|
|
return NULL; /* all the required view columns are updatable */
|
|
}
|
|
|
|
|
|
/*
|
|
* relation_is_updatable - determine which update events the specified
|
|
* relation supports.
|
|
*
|
|
* Note that views may contain a mix of updatable and non-updatable columns.
|
|
* For a view to support INSERT/UPDATE it must have at least one updatable
|
|
* column, but there is no such restriction for DELETE. If include_cols is
|
|
* non-NULL, then only the specified columns are considered when testing for
|
|
* updatability.
|
|
*
|
|
* This is used for the information_schema views, which have separate concepts
|
|
* of "updatable" and "trigger updatable". A relation is "updatable" if it
|
|
* can be updated without the need for triggers (either because it has a
|
|
* suitable RULE, or because it is simple enough to be automatically updated).
|
|
* A relation is "trigger updatable" if it has a suitable INSTEAD OF trigger.
|
|
* The SQL standard regards this as not necessarily updatable, presumably
|
|
* because there is no way of knowing what the trigger will actually do.
|
|
* The information_schema views therefore call this function with
|
|
* include_triggers = false. However, other callers might only care whether
|
|
* data-modifying SQL will work, so they can pass include_triggers = true
|
|
* to have trigger updatability included in the result.
|
|
*
|
|
* The return value is a bitmask of rule event numbers indicating which of
|
|
* the INSERT, UPDATE and DELETE operations are supported. (We do it this way
|
|
* so that we can test for UPDATE plus DELETE support in a single call.)
|
|
*/
|
|
int
|
|
relation_is_updatable(Oid reloid,
|
|
bool include_triggers,
|
|
Bitmapset *include_cols)
|
|
{
|
|
int events = 0;
|
|
Relation rel;
|
|
RuleLock *rulelocks;
|
|
|
|
#define ALL_EVENTS ((1 << CMD_INSERT) | (1 << CMD_UPDATE) | (1 << CMD_DELETE))
|
|
|
|
rel = try_relation_open(reloid, AccessShareLock);
|
|
|
|
/*
|
|
* If the relation doesn't exist, return zero rather than throwing an
|
|
* error. This is helpful since scanning an information_schema view under
|
|
* MVCC rules can result in referencing rels that have actually been
|
|
* deleted already.
|
|
*/
|
|
if (rel == NULL)
|
|
return 0;
|
|
|
|
/* If the relation is a table, it is always updatable */
|
|
if (rel->rd_rel->relkind == RELKIND_RELATION)
|
|
{
|
|
relation_close(rel, AccessShareLock);
|
|
return ALL_EVENTS;
|
|
}
|
|
|
|
/* Look for unconditional DO INSTEAD rules, and note supported events */
|
|
rulelocks = rel->rd_rules;
|
|
if (rulelocks != NULL)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < rulelocks->numLocks; i++)
|
|
{
|
|
if (rulelocks->rules[i]->isInstead &&
|
|
rulelocks->rules[i]->qual == NULL)
|
|
{
|
|
events |= ((1 << rulelocks->rules[i]->event) & ALL_EVENTS);
|
|
}
|
|
}
|
|
|
|
/* If we have rules for all events, we're done */
|
|
if (events == ALL_EVENTS)
|
|
{
|
|
relation_close(rel, AccessShareLock);
|
|
return events;
|
|
}
|
|
}
|
|
|
|
/* Similarly look for INSTEAD OF triggers, if they are to be included */
|
|
if (include_triggers)
|
|
{
|
|
TriggerDesc *trigDesc = rel->trigdesc;
|
|
|
|
if (trigDesc)
|
|
{
|
|
if (trigDesc->trig_insert_instead_row)
|
|
events |= (1 << CMD_INSERT);
|
|
if (trigDesc->trig_update_instead_row)
|
|
events |= (1 << CMD_UPDATE);
|
|
if (trigDesc->trig_delete_instead_row)
|
|
events |= (1 << CMD_DELETE);
|
|
|
|
/* If we have triggers for all events, we're done */
|
|
if (events == ALL_EVENTS)
|
|
{
|
|
relation_close(rel, AccessShareLock);
|
|
return events;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* If this is a foreign table, check which update events it supports */
|
|
if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
|
|
{
|
|
FdwRoutine *fdwroutine = GetFdwRoutineForRelation(rel, false);
|
|
|
|
if (fdwroutine->IsForeignRelUpdatable != NULL)
|
|
events |= fdwroutine->IsForeignRelUpdatable(rel);
|
|
else
|
|
{
|
|
/* Assume presence of executor functions is sufficient */
|
|
if (fdwroutine->ExecForeignInsert != NULL)
|
|
events |= (1 << CMD_INSERT);
|
|
if (fdwroutine->ExecForeignUpdate != NULL)
|
|
events |= (1 << CMD_UPDATE);
|
|
if (fdwroutine->ExecForeignDelete != NULL)
|
|
events |= (1 << CMD_DELETE);
|
|
}
|
|
|
|
relation_close(rel, AccessShareLock);
|
|
return events;
|
|
}
|
|
|
|
/* Check if this is an automatically updatable view */
|
|
if (rel->rd_rel->relkind == RELKIND_VIEW)
|
|
{
|
|
Query *viewquery = get_view_query(rel);
|
|
|
|
if (view_query_is_auto_updatable(viewquery, false) == NULL)
|
|
{
|
|
Bitmapset *updatable_cols;
|
|
int auto_events;
|
|
RangeTblRef *rtr;
|
|
RangeTblEntry *base_rte;
|
|
Oid baseoid;
|
|
|
|
/*
|
|
* Determine which of the view's columns are updatable. If there
|
|
* are none within the set of columns we are looking at, then the
|
|
* view doesn't support INSERT/UPDATE, but it may still support
|
|
* DELETE.
|
|
*/
|
|
view_cols_are_auto_updatable(viewquery, NULL,
|
|
&updatable_cols, NULL);
|
|
|
|
if (include_cols != NULL)
|
|
updatable_cols = bms_int_members(updatable_cols, include_cols);
|
|
|
|
if (bms_is_empty(updatable_cols))
|
|
auto_events = (1 << CMD_DELETE); /* May support DELETE */
|
|
else
|
|
auto_events = ALL_EVENTS; /* May support all events */
|
|
|
|
/*
|
|
* The base relation must also support these update commands.
|
|
* Tables are always updatable, but for any other kind of base
|
|
* relation we must do a recursive check limited to the columns
|
|
* referenced by the locally updatable columns in this view.
|
|
*/
|
|
rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
|
|
base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
|
|
Assert(base_rte->rtekind == RTE_RELATION);
|
|
|
|
if (base_rte->relkind != RELKIND_RELATION)
|
|
{
|
|
baseoid = base_rte->relid;
|
|
include_cols = adjust_view_column_set(updatable_cols,
|
|
viewquery->targetList);
|
|
auto_events &= relation_is_updatable(baseoid,
|
|
include_triggers,
|
|
include_cols);
|
|
}
|
|
events |= auto_events;
|
|
}
|
|
}
|
|
|
|
/* If we reach here, the relation may support some update commands */
|
|
relation_close(rel, AccessShareLock);
|
|
return events;
|
|
}
|
|
|
|
|
|
/*
|
|
* adjust_view_column_set - map a set of column numbers according to targetlist
|
|
*
|
|
* This is used with simply-updatable views to map column-permissions sets for
|
|
* the view columns onto the matching columns in the underlying base relation.
|
|
* The targetlist is expected to be a list of plain Vars of the underlying
|
|
* relation (as per the checks above in view_query_is_auto_updatable).
|
|
*/
|
|
static Bitmapset *
|
|
adjust_view_column_set(Bitmapset *cols, List *targetlist)
|
|
{
|
|
Bitmapset *result = NULL;
|
|
int col;
|
|
|
|
col = -1;
|
|
while ((col = bms_next_member(cols, col)) >= 0)
|
|
{
|
|
/* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
|
|
AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber;
|
|
|
|
if (attno == InvalidAttrNumber)
|
|
{
|
|
/*
|
|
* There's a whole-row reference to the view. For permissions
|
|
* purposes, treat it as a reference to each column available from
|
|
* the view. (We should *not* convert this to a whole-row
|
|
* reference to the base relation, since the view may not touch
|
|
* all columns of the base relation.)
|
|
*/
|
|
ListCell *lc;
|
|
|
|
foreach(lc, targetlist)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) lfirst(lc);
|
|
Var *var;
|
|
|
|
if (tle->resjunk)
|
|
continue;
|
|
var = (Var *) tle->expr;
|
|
Assert(IsA(var, Var));
|
|
result = bms_add_member(result,
|
|
var->varattno - FirstLowInvalidHeapAttributeNumber);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* Views do not have system columns, so we do not expect to see
|
|
* any other system attnos here. If we do find one, the error
|
|
* case will apply.
|
|
*/
|
|
TargetEntry *tle = get_tle_by_resno(targetlist, attno);
|
|
|
|
if (tle != NULL && !tle->resjunk && IsA(tle->expr, Var))
|
|
{
|
|
Var *var = (Var *) tle->expr;
|
|
|
|
result = bms_add_member(result,
|
|
var->varattno - FirstLowInvalidHeapAttributeNumber);
|
|
}
|
|
else
|
|
elog(ERROR, "attribute number %d not found in view targetlist",
|
|
attno);
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
/*
|
|
* rewriteTargetView -
|
|
* Attempt to rewrite a query where the target relation is a view, so that
|
|
* the view's base relation becomes the target relation.
|
|
*
|
|
* Note that the base relation here may itself be a view, which may or may not
|
|
* have INSTEAD OF triggers or rules to handle the update. That is handled by
|
|
* the recursion in RewriteQuery.
|
|
*/
|
|
static Query *
|
|
rewriteTargetView(Query *parsetree, Relation view)
|
|
{
|
|
Query *viewquery;
|
|
const char *auto_update_detail;
|
|
RangeTblRef *rtr;
|
|
int base_rt_index;
|
|
int new_rt_index;
|
|
RangeTblEntry *base_rte;
|
|
RangeTblEntry *view_rte;
|
|
RangeTblEntry *new_rte;
|
|
Relation base_rel;
|
|
List *view_targetlist;
|
|
ListCell *lc;
|
|
|
|
/* The view must be updatable, else fail */
|
|
viewquery = get_view_query(view);
|
|
|
|
auto_update_detail =
|
|
view_query_is_auto_updatable(viewquery,
|
|
parsetree->commandType != CMD_DELETE);
|
|
|
|
if (auto_update_detail)
|
|
{
|
|
/* messages here should match execMain.c's CheckValidResultRel */
|
|
switch (parsetree->commandType)
|
|
{
|
|
case CMD_INSERT:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
|
|
errmsg("cannot insert into view \"%s\"",
|
|
RelationGetRelationName(view)),
|
|
errdetail_internal("%s", _(auto_update_detail)),
|
|
errhint("To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule.")));
|
|
break;
|
|
case CMD_UPDATE:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
|
|
errmsg("cannot update view \"%s\"",
|
|
RelationGetRelationName(view)),
|
|
errdetail_internal("%s", _(auto_update_detail)),
|
|
errhint("To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.")));
|
|
break;
|
|
case CMD_DELETE:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
|
|
errmsg("cannot delete from view \"%s\"",
|
|
RelationGetRelationName(view)),
|
|
errdetail_internal("%s", _(auto_update_detail)),
|
|
errhint("To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.")));
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized CmdType: %d",
|
|
(int) parsetree->commandType);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* For INSERT/UPDATE the modified columns must all be updatable. Note that
|
|
* we get the modified columns from the query's targetlist, not from the
|
|
* result RTE's insertedCols and/or updatedCols set, since
|
|
* rewriteTargetListIU may have added additional targetlist entries for
|
|
* view defaults, and these must also be updatable.
|
|
*/
|
|
if (parsetree->commandType != CMD_DELETE)
|
|
{
|
|
Bitmapset *modified_cols = NULL;
|
|
char *non_updatable_col;
|
|
|
|
foreach(lc, parsetree->targetList)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) lfirst(lc);
|
|
|
|
if (!tle->resjunk)
|
|
modified_cols = bms_add_member(modified_cols,
|
|
tle->resno - FirstLowInvalidHeapAttributeNumber);
|
|
}
|
|
|
|
if (parsetree->onConflict)
|
|
{
|
|
foreach(lc, parsetree->onConflict->onConflictSet)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) lfirst(lc);
|
|
|
|
if (!tle->resjunk)
|
|
modified_cols = bms_add_member(modified_cols,
|
|
tle->resno - FirstLowInvalidHeapAttributeNumber);
|
|
}
|
|
}
|
|
|
|
auto_update_detail = view_cols_are_auto_updatable(viewquery,
|
|
modified_cols,
|
|
NULL,
|
|
&non_updatable_col);
|
|
if (auto_update_detail)
|
|
{
|
|
/*
|
|
* This is a different error, caused by an attempt to update a
|
|
* non-updatable column in an otherwise updatable view.
|
|
*/
|
|
switch (parsetree->commandType)
|
|
{
|
|
case CMD_INSERT:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot insert into column \"%s\" of view \"%s\"",
|
|
non_updatable_col,
|
|
RelationGetRelationName(view)),
|
|
errdetail_internal("%s", _(auto_update_detail))));
|
|
break;
|
|
case CMD_UPDATE:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot update column \"%s\" of view \"%s\"",
|
|
non_updatable_col,
|
|
RelationGetRelationName(view)),
|
|
errdetail_internal("%s", _(auto_update_detail))));
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized CmdType: %d",
|
|
(int) parsetree->commandType);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Locate RTE describing the view in the outer query */
|
|
view_rte = rt_fetch(parsetree->resultRelation, parsetree->rtable);
|
|
|
|
/*
|
|
* If we get here, view_query_is_auto_updatable() has verified that the
|
|
* view contains a single base relation.
|
|
*/
|
|
Assert(list_length(viewquery->jointree->fromlist) == 1);
|
|
rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
|
|
Assert(IsA(rtr, RangeTblRef));
|
|
|
|
base_rt_index = rtr->rtindex;
|
|
base_rte = rt_fetch(base_rt_index, viewquery->rtable);
|
|
Assert(base_rte->rtekind == RTE_RELATION);
|
|
|
|
/*
|
|
* Up to now, the base relation hasn't been touched at all in our query.
|
|
* We need to acquire lock on it before we try to do anything with it.
|
|
* (The subsequent recursive call of RewriteQuery will suppose that we
|
|
* already have the right lock!) Since it will become the query target
|
|
* relation, RowExclusiveLock is always the right thing.
|
|
*/
|
|
base_rel = heap_open(base_rte->relid, RowExclusiveLock);
|
|
|
|
/*
|
|
* While we have the relation open, update the RTE's relkind, just in case
|
|
* it changed since this view was made (cf. AcquireRewriteLocks).
|
|
*/
|
|
base_rte->relkind = base_rel->rd_rel->relkind;
|
|
|
|
heap_close(base_rel, NoLock);
|
|
|
|
/*
|
|
* Create a new target RTE describing the base relation, and add it to the
|
|
* outer query's rangetable. (What's happening in the next few steps is
|
|
* very much like what the planner would do to "pull up" the view into the
|
|
* outer query. Perhaps someday we should refactor things enough so that
|
|
* we can share code with the planner.)
|
|
*/
|
|
new_rte = (RangeTblEntry *) copyObject(base_rte);
|
|
parsetree->rtable = lappend(parsetree->rtable, new_rte);
|
|
new_rt_index = list_length(parsetree->rtable);
|
|
|
|
/*
|
|
* INSERTs never inherit. For UPDATE/DELETE, we use the view query's
|
|
* inheritance flag for the base relation.
|
|
*/
|
|
if (parsetree->commandType == CMD_INSERT)
|
|
new_rte->inh = false;
|
|
|
|
/*
|
|
* Make a copy of the view's targetlist, adjusting its Vars to reference
|
|
* the new target RTE, ie make their varnos be new_rt_index instead of
|
|
* base_rt_index. There can be no Vars for other rels in the tlist, so
|
|
* this is sufficient to pull up the tlist expressions for use in the
|
|
* outer query. The tlist will provide the replacement expressions used
|
|
* by ReplaceVarsFromTargetList below.
|
|
*/
|
|
view_targetlist = copyObject(viewquery->targetList);
|
|
|
|
ChangeVarNodes((Node *) view_targetlist,
|
|
base_rt_index,
|
|
new_rt_index,
|
|
0);
|
|
|
|
/*
|
|
* Mark the new target RTE for the permissions checks that we want to
|
|
* enforce against the view owner, as distinct from the query caller. At
|
|
* the relation level, require the same INSERT/UPDATE/DELETE permissions
|
|
* that the query caller needs against the view. We drop the ACL_SELECT
|
|
* bit that is presumably in new_rte->requiredPerms initially.
|
|
*
|
|
* Note: the original view RTE remains in the query's rangetable list.
|
|
* Although it will be unused in the query plan, we need it there so that
|
|
* the executor still performs appropriate permissions checks for the
|
|
* query caller's use of the view.
|
|
*/
|
|
new_rte->checkAsUser = view->rd_rel->relowner;
|
|
new_rte->requiredPerms = view_rte->requiredPerms;
|
|
|
|
/*
|
|
* Now for the per-column permissions bits.
|
|
*
|
|
* Initially, new_rte contains selectedCols permission check bits for all
|
|
* base-rel columns referenced by the view, but since the view is a SELECT
|
|
* query its insertedCols/updatedCols is empty. We set insertedCols and
|
|
* updatedCols to include all the columns the outer query is trying to
|
|
* modify, adjusting the column numbers as needed. But we leave
|
|
* selectedCols as-is, so the view owner must have read permission for all
|
|
* columns used in the view definition, even if some of them are not read
|
|
* by the outer query. We could try to limit selectedCols to only columns
|
|
* used in the transformed query, but that does not correspond to what
|
|
* happens in ordinary SELECT usage of a view: all referenced columns must
|
|
* have read permission, even if optimization finds that some of them can
|
|
* be discarded during query transformation. The flattening we're doing
|
|
* here is an optional optimization, too. (If you are unpersuaded and
|
|
* want to change this, note that applying adjust_view_column_set to
|
|
* view_rte->selectedCols is clearly *not* the right answer, since that
|
|
* neglects base-rel columns used in the view's WHERE quals.)
|
|
*
|
|
* This step needs the modified view targetlist, so we have to do things
|
|
* in this order.
|
|
*/
|
|
Assert(bms_is_empty(new_rte->insertedCols) &&
|
|
bms_is_empty(new_rte->updatedCols));
|
|
|
|
new_rte->insertedCols = adjust_view_column_set(view_rte->insertedCols,
|
|
view_targetlist);
|
|
|
|
new_rte->updatedCols = adjust_view_column_set(view_rte->updatedCols,
|
|
view_targetlist);
|
|
|
|
/*
|
|
* Move any security barrier quals from the view RTE onto the new target
|
|
* RTE. Any such quals should now apply to the new target RTE and will
|
|
* not reference the original view RTE in the rewritten query.
|
|
*/
|
|
new_rte->securityQuals = view_rte->securityQuals;
|
|
view_rte->securityQuals = NIL;
|
|
|
|
/*
|
|
* For UPDATE/DELETE, rewriteTargetListUD will have added a wholerow junk
|
|
* TLE for the view to the end of the targetlist, which we no longer need.
|
|
* Remove it to avoid unnecessary work when we process the targetlist.
|
|
* Note that when we recurse through rewriteQuery a new junk TLE will be
|
|
* added to allow the executor to find the proper row in the new target
|
|
* relation. (So, if we failed to do this, we might have multiple junk
|
|
* TLEs with the same name, which would be disastrous.)
|
|
*/
|
|
if (parsetree->commandType != CMD_INSERT)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) llast(parsetree->targetList);
|
|
|
|
Assert(tle->resjunk);
|
|
Assert(IsA(tle->expr, Var) &&
|
|
((Var *) tle->expr)->varno == parsetree->resultRelation &&
|
|
((Var *) tle->expr)->varattno == 0);
|
|
parsetree->targetList = list_delete_ptr(parsetree->targetList, tle);
|
|
}
|
|
|
|
/*
|
|
* Now update all Vars in the outer query that reference the view to
|
|
* reference the appropriate column of the base relation instead.
|
|
*/
|
|
parsetree = (Query *)
|
|
ReplaceVarsFromTargetList((Node *) parsetree,
|
|
parsetree->resultRelation,
|
|
0,
|
|
view_rte,
|
|
view_targetlist,
|
|
REPLACEVARS_REPORT_ERROR,
|
|
0,
|
|
&parsetree->hasSubLinks);
|
|
|
|
/*
|
|
* Update all other RTI references in the query that point to the view
|
|
* (for example, parsetree->resultRelation itself) to point to the new
|
|
* base relation instead. Vars will not be affected since none of them
|
|
* reference parsetree->resultRelation any longer.
|
|
*/
|
|
ChangeVarNodes((Node *) parsetree,
|
|
parsetree->resultRelation,
|
|
new_rt_index,
|
|
0);
|
|
Assert(parsetree->resultRelation == new_rt_index);
|
|
|
|
/*
|
|
* For INSERT/UPDATE we must also update resnos in the targetlist to refer
|
|
* to columns of the base relation, since those indicate the target
|
|
* columns to be affected.
|
|
*
|
|
* Note that this destroys the resno ordering of the targetlist, but that
|
|
* will be fixed when we recurse through rewriteQuery, which will invoke
|
|
* rewriteTargetListIU again on the updated targetlist.
|
|
*/
|
|
if (parsetree->commandType != CMD_DELETE)
|
|
{
|
|
foreach(lc, parsetree->targetList)
|
|
{
|
|
TargetEntry *tle = (TargetEntry *) lfirst(lc);
|
|
TargetEntry *view_tle;
|
|
|
|
if (tle->resjunk)
|
|
continue;
|
|
|
|
view_tle = get_tle_by_resno(view_targetlist, tle->resno);
|
|
if (view_tle != NULL && !view_tle->resjunk && IsA(view_tle->expr, Var))
|
|
tle->resno = ((Var *) view_tle->expr)->varattno;
|
|
else
|
|
elog(ERROR, "attribute number %d not found in view targetlist",
|
|
tle->resno);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* For UPDATE/DELETE, pull up any WHERE quals from the view. We know that
|
|
* any Vars in the quals must reference the one base relation, so we need
|
|
* only adjust their varnos to reference the new target (just the same as
|
|
* we did with the view targetlist).
|
|
*
|
|
* Note that there is special-case handling for the quals of a security
|
|
* barrier view, since they need to be kept separate from any
|
|
* user-supplied quals, so these quals are kept on the new target RTE.
|
|
*
|
|
* For INSERT, the view's quals can be ignored in the main query.
|
|
*/
|
|
if (parsetree->commandType != CMD_INSERT &&
|
|
viewquery->jointree->quals != NULL)
|
|
{
|
|
Node *viewqual = (Node *) copyObject(viewquery->jointree->quals);
|
|
|
|
ChangeVarNodes(viewqual, base_rt_index, new_rt_index, 0);
|
|
|
|
if (RelationIsSecurityView(view))
|
|
{
|
|
/*
|
|
* Note: the parsetree has been mutated, so the new_rte pointer is
|
|
* stale and needs to be re-computed.
|
|
*/
|
|
new_rte = rt_fetch(new_rt_index, parsetree->rtable);
|
|
new_rte->securityQuals = lcons(viewqual, new_rte->securityQuals);
|
|
|
|
/*
|
|
* Make sure that the query is marked correctly if the added qual
|
|
* has sublinks.
|
|
*/
|
|
if (!parsetree->hasSubLinks)
|
|
parsetree->hasSubLinks = checkExprHasSubLink(viewqual);
|
|
}
|
|
else
|
|
AddQual(parsetree, (Node *) viewqual);
|
|
}
|
|
|
|
/*
|
|
* For INSERT/UPDATE, if the view has the WITH CHECK OPTION, or any parent
|
|
* view specified WITH CASCADED CHECK OPTION, add the quals from the view
|
|
* to the query's withCheckOptions list.
|
|
*/
|
|
if (parsetree->commandType != CMD_DELETE)
|
|
{
|
|
bool has_wco = RelationHasCheckOption(view);
|
|
bool cascaded = RelationHasCascadedCheckOption(view);
|
|
|
|
/*
|
|
* If the parent view has a cascaded check option, treat this view as
|
|
* if it also had a cascaded check option.
|
|
*
|
|
* New WithCheckOptions are added to the start of the list, so if
|
|
* there is a cascaded check option, it will be the first item in the
|
|
* list.
|
|
*/
|
|
if (parsetree->withCheckOptions != NIL)
|
|
{
|
|
WithCheckOption *parent_wco =
|
|
(WithCheckOption *) linitial(parsetree->withCheckOptions);
|
|
|
|
if (parent_wco->cascaded)
|
|
{
|
|
has_wco = true;
|
|
cascaded = true;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Add the new WithCheckOption to the start of the list, so that
|
|
* checks on inner views are run before checks on outer views, as
|
|
* required by the SQL standard.
|
|
*
|
|
* If the new check is CASCADED, we need to add it even if this view
|
|
* has no quals, since there may be quals on child views. A LOCAL
|
|
* check can be omitted if this view has no quals.
|
|
*/
|
|
if (has_wco && (cascaded || viewquery->jointree->quals != NULL))
|
|
{
|
|
WithCheckOption *wco;
|
|
|
|
wco = makeNode(WithCheckOption);
|
|
wco->kind = WCO_VIEW_CHECK;
|
|
wco->relname = pstrdup(RelationGetRelationName(view));
|
|
wco->qual = NULL;
|
|
wco->cascaded = cascaded;
|
|
|
|
parsetree->withCheckOptions = lcons(wco,
|
|
parsetree->withCheckOptions);
|
|
|
|
if (viewquery->jointree->quals != NULL)
|
|
{
|
|
wco->qual = (Node *) copyObject(viewquery->jointree->quals);
|
|
ChangeVarNodes(wco->qual, base_rt_index, new_rt_index, 0);
|
|
|
|
/*
|
|
* Make sure that the query is marked correctly if the added
|
|
* qual has sublinks. We can skip this check if the query is
|
|
* already marked, or if the command is an UPDATE, in which
|
|
* case the same qual will have already been added, and this
|
|
* check will already have been done.
|
|
*/
|
|
if (!parsetree->hasSubLinks &&
|
|
parsetree->commandType != CMD_UPDATE)
|
|
parsetree->hasSubLinks = checkExprHasSubLink(wco->qual);
|
|
}
|
|
}
|
|
}
|
|
|
|
return parsetree;
|
|
}
|
|
|
|
|
|
/*
|
|
* RewriteQuery -
|
|
* rewrites the query and apply the rules again on the queries rewritten
|
|
*
|
|
* rewrite_events is a list of open query-rewrite actions, so we can detect
|
|
* infinite recursion.
|
|
*/
|
|
static List *
|
|
RewriteQuery(Query *parsetree, List *rewrite_events)
|
|
{
|
|
CmdType event = parsetree->commandType;
|
|
bool instead = false;
|
|
bool returning = false;
|
|
bool updatableview = false;
|
|
Query *qual_product = NULL;
|
|
List *rewritten = NIL;
|
|
ListCell *lc1;
|
|
|
|
/*
|
|
* First, recursively process any insert/update/delete statements in WITH
|
|
* clauses. (We have to do this first because the WITH clauses may get
|
|
* copied into rule actions below.)
|
|
*/
|
|
foreach(lc1, parsetree->cteList)
|
|
{
|
|
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc1);
|
|
Query *ctequery = (Query *) cte->ctequery;
|
|
List *newstuff;
|
|
|
|
Assert(IsA(ctequery, Query));
|
|
|
|
if (ctequery->commandType == CMD_SELECT)
|
|
continue;
|
|
|
|
newstuff = RewriteQuery(ctequery, rewrite_events);
|
|
|
|
/*
|
|
* Currently we can only handle unconditional, single-statement DO
|
|
* INSTEAD rules correctly; we have to get exactly one Query out of
|
|
* the rewrite operation to stuff back into the CTE node.
|
|
*/
|
|
if (list_length(newstuff) == 1)
|
|
{
|
|
/* Push the single Query back into the CTE node */
|
|
ctequery = (Query *) linitial(newstuff);
|
|
Assert(IsA(ctequery, Query));
|
|
/* WITH queries should never be canSetTag */
|
|
Assert(!ctequery->canSetTag);
|
|
cte->ctequery = (Node *) ctequery;
|
|
}
|
|
else if (newstuff == NIL)
|
|
{
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("DO INSTEAD NOTHING rules are not supported for data-modifying statements in WITH")));
|
|
}
|
|
else
|
|
{
|
|
ListCell *lc2;
|
|
|
|
/* examine queries to determine which error message to issue */
|
|
foreach(lc2, newstuff)
|
|
{
|
|
Query *q = (Query *) lfirst(lc2);
|
|
|
|
if (q->querySource == QSRC_QUAL_INSTEAD_RULE)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("conditional DO INSTEAD rules are not supported for data-modifying statements in WITH")));
|
|
if (q->querySource == QSRC_NON_INSTEAD_RULE)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("DO ALSO rules are not supported for data-modifying statements in WITH")));
|
|
}
|
|
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("multi-statement DO INSTEAD rules are not supported for data-modifying statements in WITH")));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the statement is an insert, update, or delete, adjust its targetlist
|
|
* as needed, and then fire INSERT/UPDATE/DELETE rules on it.
|
|
*
|
|
* SELECT rules are handled later when we have all the queries that should
|
|
* get executed. Also, utilities aren't rewritten at all (do we still
|
|
* need that check?)
|
|
*/
|
|
if (event != CMD_SELECT && event != CMD_UTILITY)
|
|
{
|
|
int result_relation;
|
|
RangeTblEntry *rt_entry;
|
|
Relation rt_entry_relation;
|
|
List *locks;
|
|
List *product_queries;
|
|
bool hasUpdate = false;
|
|
|
|
result_relation = parsetree->resultRelation;
|
|
Assert(result_relation != 0);
|
|
rt_entry = rt_fetch(result_relation, parsetree->rtable);
|
|
Assert(rt_entry->rtekind == RTE_RELATION);
|
|
|
|
/*
|
|
* We can use NoLock here since either the parser or
|
|
* AcquireRewriteLocks should have locked the rel already.
|
|
*/
|
|
rt_entry_relation = heap_open(rt_entry->relid, NoLock);
|
|
|
|
/*
|
|
* Rewrite the targetlist as needed for the command type.
|
|
*/
|
|
if (event == CMD_INSERT)
|
|
{
|
|
RangeTblEntry *values_rte = NULL;
|
|
|
|
/*
|
|
* If it's an INSERT ... VALUES (...), (...), ... there will be a
|
|
* single RTE for the VALUES targetlists.
|
|
*/
|
|
if (list_length(parsetree->jointree->fromlist) == 1)
|
|
{
|
|
RangeTblRef *rtr = (RangeTblRef *) linitial(parsetree->jointree->fromlist);
|
|
|
|
if (IsA(rtr, RangeTblRef))
|
|
{
|
|
RangeTblEntry *rte = rt_fetch(rtr->rtindex,
|
|
parsetree->rtable);
|
|
|
|
if (rte->rtekind == RTE_VALUES)
|
|
values_rte = rte;
|
|
}
|
|
}
|
|
|
|
if (values_rte)
|
|
{
|
|
List *attrnos;
|
|
|
|
/* Process the main targetlist ... */
|
|
parsetree->targetList = rewriteTargetListIU(parsetree->targetList,
|
|
parsetree->commandType,
|
|
rt_entry_relation,
|
|
parsetree->resultRelation,
|
|
&attrnos);
|
|
/* ... and the VALUES expression lists */
|
|
rewriteValuesRTE(values_rte, rt_entry_relation, attrnos);
|
|
}
|
|
else
|
|
{
|
|
/* Process just the main targetlist */
|
|
parsetree->targetList =
|
|
rewriteTargetListIU(parsetree->targetList,
|
|
parsetree->commandType,
|
|
rt_entry_relation,
|
|
parsetree->resultRelation, NULL);
|
|
}
|
|
|
|
if (parsetree->onConflict &&
|
|
parsetree->onConflict->action == ONCONFLICT_UPDATE)
|
|
{
|
|
parsetree->onConflict->onConflictSet =
|
|
rewriteTargetListIU(parsetree->onConflict->onConflictSet,
|
|
CMD_UPDATE,
|
|
rt_entry_relation,
|
|
parsetree->resultRelation,
|
|
NULL);
|
|
}
|
|
}
|
|
else if (event == CMD_UPDATE)
|
|
{
|
|
parsetree->targetList =
|
|
rewriteTargetListIU(parsetree->targetList,
|
|
parsetree->commandType, rt_entry_relation,
|
|
parsetree->resultRelation, NULL);
|
|
rewriteTargetListUD(parsetree, rt_entry, rt_entry_relation);
|
|
}
|
|
else if (event == CMD_DELETE)
|
|
{
|
|
rewriteTargetListUD(parsetree, rt_entry, rt_entry_relation);
|
|
}
|
|
else
|
|
elog(ERROR, "unrecognized commandType: %d", (int) event);
|
|
|
|
/*
|
|
* Collect and apply the appropriate rules.
|
|
*/
|
|
locks = matchLocks(event, rt_entry_relation->rd_rules,
|
|
result_relation, parsetree, &hasUpdate);
|
|
|
|
product_queries = fireRules(parsetree,
|
|
result_relation,
|
|
event,
|
|
locks,
|
|
&instead,
|
|
&returning,
|
|
&qual_product);
|
|
|
|
/*
|
|
* If there were no INSTEAD rules, and the target relation is a view
|
|
* without any INSTEAD OF triggers, see if the view can be
|
|
* automatically updated. If so, we perform the necessary query
|
|
* transformation here and add the resulting query to the
|
|
* product_queries list, so that it gets recursively rewritten if
|
|
* necessary.
|
|
*/
|
|
if (!instead && qual_product == NULL &&
|
|
rt_entry_relation->rd_rel->relkind == RELKIND_VIEW &&
|
|
!view_has_instead_trigger(rt_entry_relation, event))
|
|
{
|
|
/*
|
|
* This throws an error if the view can't be automatically
|
|
* updated, but that's OK since the query would fail at runtime
|
|
* anyway.
|
|
*/
|
|
parsetree = rewriteTargetView(parsetree, rt_entry_relation);
|
|
|
|
/*
|
|
* At this point product_queries contains any DO ALSO rule
|
|
* actions. Add the rewritten query before or after those. This
|
|
* must match the handling the original query would have gotten
|
|
* below, if we allowed it to be included again.
|
|
*/
|
|
if (parsetree->commandType == CMD_INSERT)
|
|
product_queries = lcons(parsetree, product_queries);
|
|
else
|
|
product_queries = lappend(product_queries, parsetree);
|
|
|
|
/*
|
|
* Set the "instead" flag, as if there had been an unqualified
|
|
* INSTEAD, to prevent the original query from being included a
|
|
* second time below. The transformation will have rewritten any
|
|
* RETURNING list, so we can also set "returning" to forestall
|
|
* throwing an error below.
|
|
*/
|
|
instead = true;
|
|
returning = true;
|
|
updatableview = true;
|
|
}
|
|
|
|
/*
|
|
* If we got any product queries, recursively rewrite them --- but
|
|
* first check for recursion!
|
|
*/
|
|
if (product_queries != NIL)
|
|
{
|
|
ListCell *n;
|
|
rewrite_event *rev;
|
|
|
|
foreach(n, rewrite_events)
|
|
{
|
|
rev = (rewrite_event *) lfirst(n);
|
|
if (rev->relation == RelationGetRelid(rt_entry_relation) &&
|
|
rev->event == event)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
|
|
errmsg("infinite recursion detected in rules for relation \"%s\"",
|
|
RelationGetRelationName(rt_entry_relation))));
|
|
}
|
|
|
|
rev = (rewrite_event *) palloc(sizeof(rewrite_event));
|
|
rev->relation = RelationGetRelid(rt_entry_relation);
|
|
rev->event = event;
|
|
rewrite_events = lcons(rev, rewrite_events);
|
|
|
|
foreach(n, product_queries)
|
|
{
|
|
Query *pt = (Query *) lfirst(n);
|
|
List *newstuff;
|
|
|
|
newstuff = RewriteQuery(pt, rewrite_events);
|
|
rewritten = list_concat(rewritten, newstuff);
|
|
}
|
|
|
|
rewrite_events = list_delete_first(rewrite_events);
|
|
}
|
|
|
|
/*
|
|
* If there is an INSTEAD, and the original query has a RETURNING, we
|
|
* have to have found a RETURNING in the rule(s), else fail. (Because
|
|
* DefineQueryRewrite only allows RETURNING in unconditional INSTEAD
|
|
* rules, there's no need to worry whether the substituted RETURNING
|
|
* will actually be executed --- it must be.)
|
|
*/
|
|
if ((instead || qual_product != NULL) &&
|
|
parsetree->returningList &&
|
|
!returning)
|
|
{
|
|
switch (event)
|
|
{
|
|
case CMD_INSERT:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot perform INSERT RETURNING on relation \"%s\"",
|
|
RelationGetRelationName(rt_entry_relation)),
|
|
errhint("You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause.")));
|
|
break;
|
|
case CMD_UPDATE:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot perform UPDATE RETURNING on relation \"%s\"",
|
|
RelationGetRelationName(rt_entry_relation)),
|
|
errhint("You need an unconditional ON UPDATE DO INSTEAD rule with a RETURNING clause.")));
|
|
break;
|
|
case CMD_DELETE:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot perform DELETE RETURNING on relation \"%s\"",
|
|
RelationGetRelationName(rt_entry_relation)),
|
|
errhint("You need an unconditional ON DELETE DO INSTEAD rule with a RETURNING clause.")));
|
|
break;
|
|
default:
|
|
elog(ERROR, "unrecognized commandType: %d",
|
|
(int) event);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Updatable views are supported by ON CONFLICT, so don't prevent that
|
|
* case from proceeding
|
|
*/
|
|
if (parsetree->onConflict &&
|
|
(product_queries != NIL || hasUpdate) &&
|
|
!updatableview)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("INSERT with ON CONFLICT clause cannot be used with table that has INSERT or UPDATE rules")));
|
|
|
|
heap_close(rt_entry_relation, NoLock);
|
|
}
|
|
|
|
/*
|
|
* For INSERTs, the original query is done first; for UPDATE/DELETE, it is
|
|
* done last. This is needed because update and delete rule actions might
|
|
* not do anything if they are invoked after the update or delete is
|
|
* performed. The command counter increment between the query executions
|
|
* makes the deleted (and maybe the updated) tuples disappear so the scans
|
|
* for them in the rule actions cannot find them.
|
|
*
|
|
* If we found any unqualified INSTEAD, the original query is not done at
|
|
* all, in any form. Otherwise, we add the modified form if qualified
|
|
* INSTEADs were found, else the unmodified form.
|
|
*/
|
|
if (!instead)
|
|
{
|
|
if (parsetree->commandType == CMD_INSERT)
|
|
{
|
|
if (qual_product != NULL)
|
|
rewritten = lcons(qual_product, rewritten);
|
|
else
|
|
rewritten = lcons(parsetree, rewritten);
|
|
}
|
|
else
|
|
{
|
|
if (qual_product != NULL)
|
|
rewritten = lappend(rewritten, qual_product);
|
|
else
|
|
rewritten = lappend(rewritten, parsetree);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the original query has a CTE list, and we generated more than one
|
|
* non-utility result query, we have to fail because we'll have copied the
|
|
* CTE list into each result query. That would break the expectation of
|
|
* single evaluation of CTEs. This could possibly be fixed by
|
|
* restructuring so that a CTE list can be shared across multiple Query
|
|
* and PlannableStatement nodes.
|
|
*/
|
|
if (parsetree->cteList != NIL)
|
|
{
|
|
int qcount = 0;
|
|
|
|
foreach(lc1, rewritten)
|
|
{
|
|
Query *q = (Query *) lfirst(lc1);
|
|
|
|
if (q->commandType != CMD_UTILITY)
|
|
qcount++;
|
|
}
|
|
if (qcount > 1)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("WITH cannot be used in a query that is rewritten by rules into multiple queries")));
|
|
}
|
|
|
|
return rewritten;
|
|
}
|
|
|
|
|
|
/*
|
|
* QueryRewrite -
|
|
* Primary entry point to the query rewriter.
|
|
* Rewrite one query via query rewrite system, possibly returning 0
|
|
* or many queries.
|
|
*
|
|
* NOTE: the parsetree must either have come straight from the parser,
|
|
* or have been scanned by AcquireRewriteLocks to acquire suitable locks.
|
|
*/
|
|
List *
|
|
QueryRewrite(Query *parsetree)
|
|
{
|
|
uint32 input_query_id = parsetree->queryId;
|
|
List *querylist;
|
|
List *results;
|
|
ListCell *l;
|
|
CmdType origCmdType;
|
|
bool foundOriginalQuery;
|
|
Query *lastInstead;
|
|
|
|
/*
|
|
* This function is only applied to top-level original queries
|
|
*/
|
|
Assert(parsetree->querySource == QSRC_ORIGINAL);
|
|
Assert(parsetree->canSetTag);
|
|
|
|
/*
|
|
* Step 1
|
|
*
|
|
* Apply all non-SELECT rules possibly getting 0 or many queries
|
|
*/
|
|
querylist = RewriteQuery(parsetree, NIL);
|
|
|
|
/*
|
|
* Step 2
|
|
*
|
|
* Apply all the RIR rules on each query
|
|
*
|
|
* This is also a handy place to mark each query with the original queryId
|
|
*/
|
|
results = NIL;
|
|
foreach(l, querylist)
|
|
{
|
|
Query *query = (Query *) lfirst(l);
|
|
|
|
query = fireRIRrules(query, NIL, false);
|
|
|
|
query->queryId = input_query_id;
|
|
|
|
results = lappend(results, query);
|
|
}
|
|
|
|
/*
|
|
* Step 3
|
|
*
|
|
* Determine which, if any, of the resulting queries is supposed to set
|
|
* the command-result tag; and update the canSetTag fields accordingly.
|
|
*
|
|
* If the original query is still in the list, it sets the command tag.
|
|
* Otherwise, the last INSTEAD query of the same kind as the original is
|
|
* allowed to set the tag. (Note these rules can leave us with no query
|
|
* setting the tag. The tcop code has to cope with this by setting up a
|
|
* default tag based on the original un-rewritten query.)
|
|
*
|
|
* The Asserts verify that at most one query in the result list is marked
|
|
* canSetTag. If we aren't checking asserts, we can fall out of the loop
|
|
* as soon as we find the original query.
|
|
*/
|
|
origCmdType = parsetree->commandType;
|
|
foundOriginalQuery = false;
|
|
lastInstead = NULL;
|
|
|
|
foreach(l, results)
|
|
{
|
|
Query *query = (Query *) lfirst(l);
|
|
|
|
if (query->querySource == QSRC_ORIGINAL)
|
|
{
|
|
Assert(query->canSetTag);
|
|
Assert(!foundOriginalQuery);
|
|
foundOriginalQuery = true;
|
|
#ifndef USE_ASSERT_CHECKING
|
|
break;
|
|
#endif
|
|
}
|
|
else
|
|
{
|
|
Assert(!query->canSetTag);
|
|
if (query->commandType == origCmdType &&
|
|
(query->querySource == QSRC_INSTEAD_RULE ||
|
|
query->querySource == QSRC_QUAL_INSTEAD_RULE))
|
|
lastInstead = query;
|
|
}
|
|
}
|
|
|
|
if (!foundOriginalQuery && lastInstead != NULL)
|
|
lastInstead->canSetTag = true;
|
|
|
|
return results;
|
|
}
|