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The lower case spellings are C and C++ standard and are used in most parts of the PostgreSQL sources. The upper case spellings are only used in some files/modules. So standardize on the standard spellings. The APIs for ICU, Perl, and Windows define their own TRUE and FALSE, so those are left as is when using those APIs. In code comments, we use the lower-case spelling for the C concepts and keep the upper-case spelling for the SQL concepts. Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
3666 lines
113 KiB
C
3666 lines
113 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) 1996-2017, 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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* NOTES
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* Some of the terms used in this file are of historic nature: "retrieve"
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* was the PostQUEL keyword for what today is SELECT. "RIR" stands for
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* "Retrieve-Instead-Retrieve", that is an ON SELECT DO INSTEAD SELECT rule
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* (which has to be unconditional and where only one rule can exist on each
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* relation).
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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/dependency.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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OverridingKind override,
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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 = copyObject(rule_action);
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rule_qual = 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(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_TABLEFUNC:
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sub_action->hasSubLinks =
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checkExprHasSubLink((Node *) rte->tablefunc);
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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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* Also, we might have absorbed some RTEs with RLS conditions into the
|
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* sub_action. If so, mark it as hasRowSecurity, whether or not those
|
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* RTEs will be referenced after we finish rewriting. (Note: currently
|
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* this is a no-op because RLS conditions aren't added till later, but it
|
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* seems like good future-proofing to do this anyway.)
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*/
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sub_action->hasRowSecurity |= parsetree->hasRowSecurity;
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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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|
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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));
|
|
newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
|
|
if (newjointree != NIL)
|
|
{
|
|
/*
|
|
* If sub_action is a setop, manipulating its jointree will do no
|
|
* good at all, because the jointree is dummy. (Perhaps someday
|
|
* we could push the joining and quals down to the member
|
|
* statements of the setop?)
|
|
*/
|
|
if (sub_action->setOperations != NULL)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
|
|
|
|
sub_action->jointree->fromlist =
|
|
list_concat(newjointree, sub_action->jointree->fromlist);
|
|
|
|
/*
|
|
* There could have been some SubLinks in newjointree, in which
|
|
* case we'd better mark the sub_action correctly.
|
|
*/
|
|
if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
|
|
sub_action->hasSubLinks =
|
|
checkExprHasSubLink((Node *) newjointree);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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,
|
|
OverridingKind override,
|
|
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 = TupleDescAttr(target_relation->rd_att, 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];
|
|
bool apply_default;
|
|
|
|
att_tup = TupleDescAttr(target_relation->rd_att, 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.
|
|
*/
|
|
apply_default = ((new_tle == NULL && commandType == CMD_INSERT) ||
|
|
(new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)));
|
|
|
|
if (commandType == CMD_INSERT)
|
|
{
|
|
if (att_tup->attidentity == ATTRIBUTE_IDENTITY_ALWAYS && !apply_default)
|
|
{
|
|
if (override != OVERRIDING_SYSTEM_VALUE)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_GENERATED_ALWAYS),
|
|
errmsg("cannot insert into column \"%s\"", NameStr(att_tup->attname)),
|
|
errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
|
|
NameStr(att_tup->attname)),
|
|
errhint("Use OVERRIDING SYSTEM VALUE to override.")));
|
|
}
|
|
|
|
if (att_tup->attidentity == ATTRIBUTE_IDENTITY_BY_DEFAULT && override == OVERRIDING_USER_VALUE)
|
|
apply_default = true;
|
|
}
|
|
|
|
if (commandType == CMD_UPDATE)
|
|
{
|
|
if (att_tup->attidentity == ATTRIBUTE_IDENTITY_ALWAYS && new_tle && !apply_default)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_GENERATED_ALWAYS),
|
|
errmsg("column \"%s\" can only be updated to DEFAULT", NameStr(att_tup->attname)),
|
|
errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
|
|
NameStr(att_tup->attname))));
|
|
}
|
|
|
|
if (apply_default)
|
|
{
|
|
Node *new_expr;
|
|
|
|
if (att_tup->attidentity)
|
|
{
|
|
NextValueExpr *nve = makeNode(NextValueExpr);
|
|
|
|
nve->seqid = getOwnedSequence(RelationGetRelid(target_relation), attrno);
|
|
nve->typeId = att_tup->atttypid;
|
|
|
|
new_expr = (Node *) nve;
|
|
}
|
|
else
|
|
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,
|
|
COERCION_IMPLICIT,
|
|
COERCE_IMPLICIT_CAST,
|
|
-1,
|
|
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;
|
|
CoerceToDomain *coerce_expr = NULL;
|
|
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.
|
|
*
|
|
* As a further complication, the destination column might be a domain,
|
|
* resulting in each assignment containing a CoerceToDomain node over a
|
|
* FieldStore or ArrayRef. These should have matching target domains,
|
|
* so we strip them and reconstitute a single CoerceToDomain over the
|
|
* combined FieldStore/ArrayRef nodes. (Notice that this has the result
|
|
* that the domain's checks are applied only after we do all the field or
|
|
* element updates, not after each one. This is arguably desirable.)
|
|
*----------
|
|
*/
|
|
src_expr = (Node *) src_tle->expr;
|
|
prior_expr = (Node *) prior_tle->expr;
|
|
|
|
if (src_expr && IsA(src_expr, CoerceToDomain) &&
|
|
prior_expr && IsA(prior_expr, CoerceToDomain) &&
|
|
((CoerceToDomain *) src_expr)->resulttype ==
|
|
((CoerceToDomain *) prior_expr)->resulttype)
|
|
{
|
|
/* we assume without checking that resulttypmod/resultcollid match */
|
|
coerce_expr = (CoerceToDomain *) src_expr;
|
|
src_expr = (Node *) ((CoerceToDomain *) src_expr)->arg;
|
|
prior_expr = (Node *) ((CoerceToDomain *) prior_expr)->arg;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
if (coerce_expr)
|
|
{
|
|
/* put back the CoerceToDomain */
|
|
CoerceToDomain *newcoerce = makeNode(CoerceToDomain);
|
|
|
|
memcpy(newcoerce, coerce_expr, sizeof(CoerceToDomain));
|
|
newcoerce->arg = (Expr *) newexpr;
|
|
newexpr = (Node *) newcoerce;
|
|
}
|
|
|
|
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 = TupleDescAttr(rd_att, 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 = TupleDescAttr(target_relation->rd_att, 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,
|
|
COERCION_IMPLICIT,
|
|
COERCE_IMPLICIT_CAST,
|
|
-1,
|
|
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 ||
|
|
target_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
|
|
{
|
|
/*
|
|
* 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 &&
|
|
rte->relkind != RELKIND_PARTITIONED_TABLE))
|
|
continue;
|
|
|
|
rel = heap_open(rte->relid, NoLock);
|
|
|
|
/*
|
|
* Fetch any new security quals that must be applied to this RTE.
|
|
*/
|
|
get_row_security_policies(parsetree, rte, rt_index,
|
|
&securityQuals, &withCheckOptions,
|
|
&hasRowSecurity, &hasSubLinks);
|
|
|
|
if (securityQuals != NIL || withCheckOptions != NIL)
|
|
{
|
|
if (hasSubLinks)
|
|
{
|
|
acquireLocksOnSubLinks_context context;
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/*
|
|
* get_row_security_policies just passed back securityQuals
|
|
* and/or withCheckOptions, and there were SubLinks, make sure
|
|
* we lock any relations which are referenced.
|
|
*
|
|
* These locks would normally be acquired by the parser, but
|
|
* securityQuals and withCheckOptions are added post-parsing.
|
|
*/
|
|
context.for_execute = true;
|
|
(void) acquireLocksOnSubLinks((Node *) securityQuals, &context);
|
|
(void) acquireLocksOnSubLinks((Node *) withCheckOptions,
|
|
&context);
|
|
|
|
/*
|
|
* Now that we have the locks on anything added by
|
|
* get_row_security_policies, fire any RIR rules for them.
|
|
*/
|
|
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 barrier quals to the start of the RTE's
|
|
* list so that they get applied before any existing barrier quals
|
|
* (which would have come from a security-barrier view, and should
|
|
* get lower priority than RLS conditions on the table itself).
|
|
*/
|
|
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 = 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.
|
|
*
|
|
* Note that the pointer returned is into the relcache and therefore must
|
|
* be treated as read-only to the caller and not modified or scribbled on.
|
|
*/
|
|
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 (viewquery->hasTargetSRFs)
|
|
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 &&
|
|
base_rte->relkind != RELKIND_PARTITIONED_TABLE))
|
|
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 = linitial_node(RangeTblRef, viewquery->jointree->fromlist);
|
|
|
|
/* 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 ||
|
|
rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
|
|
{
|
|
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 &&
|
|
base_rte->relkind != RELKIND_PARTITIONED_TABLE)
|
|
{
|
|
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 = lfirst_node(TargetEntry, lc);
|
|
Var *var;
|
|
|
|
if (tle->resjunk)
|
|
continue;
|
|
var = castNode(Var, tle->expr);
|
|
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;
|
|
|
|
/*
|
|
* Get the Query from the view's ON SELECT rule. We're going to munge the
|
|
* Query to change the view's base relation into the target relation,
|
|
* along with various other changes along the way, so we need to make a
|
|
* copy of it (get_view_query() returns a pointer into the relcache, so we
|
|
* have to treat it as read-only).
|
|
*/
|
|
viewquery = copyObject(get_view_query(view));
|
|
|
|
/* The view must be updatable, else fail */
|
|
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 = linitial_node(RangeTblRef, viewquery->jointree->fromlist);
|
|
|
|
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);
|
|
|
|
/*
|
|
* If the view query contains any sublink subqueries then we need to also
|
|
* acquire locks on any relations they refer to. We know that there won't
|
|
* be any subqueries in the range table or CTEs, so we can skip those, as
|
|
* in AcquireRewriteLocks.
|
|
*/
|
|
if (viewquery->hasSubLinks)
|
|
{
|
|
acquireLocksOnSubLinks_context context;
|
|
|
|
context.for_execute = true;
|
|
query_tree_walker(viewquery, acquireLocksOnSubLinks, &context,
|
|
QTW_IGNORE_RC_SUBQUERIES);
|
|
}
|
|
|
|
/*
|
|
* 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 *) 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;
|
|
|
|
/*
|
|
* Adjust the view's targetlist 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 = 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).
|
|
*
|
|
* If it's a security-barrier view, its WHERE quals must be applied before
|
|
* quals from the outer query, so we attach them to the RTE as security
|
|
* barrier quals rather than adding them to the main WHERE clause.
|
|
*
|
|
* 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 *) viewquery->jointree->quals;
|
|
|
|
/*
|
|
* Even though we copied viewquery already at the top of this
|
|
* function, we must duplicate the viewqual again here, because we may
|
|
* need to use the quals again below for a WithCheckOption clause.
|
|
*/
|
|
viewqual = copyObject(viewqual);
|
|
|
|
ChangeVarNodes(viewqual, base_rt_index, new_rt_index, 0);
|
|
|
|
if (RelationIsSecurityView(view))
|
|
{
|
|
/*
|
|
* The view's quals go in front of existing barrier quals: those
|
|
* would have come from an outer level of security-barrier view,
|
|
* and so must get evaluated later.
|
|
*
|
|
* 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);
|
|
|
|
/*
|
|
* Do not set parsetree->hasRowSecurity, because these aren't RLS
|
|
* conditions (they aren't affected by enabling/disabling RLS).
|
|
*/
|
|
|
|
/*
|
|
* 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->polname = NULL;
|
|
wco->qual = NULL;
|
|
wco->cascaded = cascaded;
|
|
|
|
parsetree->withCheckOptions = lcons(wco,
|
|
parsetree->withCheckOptions);
|
|
|
|
if (viewquery->jointree->quals != NULL)
|
|
{
|
|
wco->qual = (Node *) 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 = lfirst_node(CommonTableExpr, lc1);
|
|
Query *ctequery = castNode(Query, cte->ctequery);
|
|
List *newstuff;
|
|
|
|
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 = linitial_node(Query, newstuff);
|
|
/* 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,
|
|
parsetree->override,
|
|
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,
|
|
parsetree->override,
|
|
rt_entry_relation,
|
|
parsetree->resultRelation, NULL);
|
|
}
|
|
|
|
if (parsetree->onConflict &&
|
|
parsetree->onConflict->action == ONCONFLICT_UPDATE)
|
|
{
|
|
parsetree->onConflict->onConflictSet =
|
|
rewriteTargetListIU(parsetree->onConflict->onConflictSet,
|
|
CMD_UPDATE,
|
|
parsetree->override,
|
|
rt_entry_relation,
|
|
parsetree->resultRelation,
|
|
NULL);
|
|
}
|
|
}
|
|
else if (event == CMD_UPDATE)
|
|
{
|
|
parsetree->targetList =
|
|
rewriteTargetListIU(parsetree->targetList,
|
|
parsetree->commandType,
|
|
parsetree->override,
|
|
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)
|
|
{
|
|
uint64 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;
|
|
}
|