PostgreSQL Source Code  git master
rewriteHandler.h File Reference
#include "nodes/parsenodes.h"
#include "utils/relcache.h"
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Functions

ListQueryRewrite (Query *parsetree)
 
void AcquireRewriteLocks (Query *parsetree, bool forExecute, bool forUpdatePushedDown)
 
Nodebuild_column_default (Relation rel, int attrno)
 
void rewriteTargetListUD (Query *parsetree, RangeTblEntry *target_rte, Relation target_relation)
 
Queryget_view_query (Relation view)
 
const char * view_query_is_auto_updatable (Query *viewquery, bool check_cols)
 
int relation_is_updatable (Oid reloid, List *outer_reloids, bool include_triggers, Bitmapset *include_cols)
 

Function Documentation

◆ AcquireRewriteLocks()

void AcquireRewriteLocks ( Query parsetree,
bool  forExecute,
bool  forUpdatePushedDown 
)

Definition at line 133 of file rewriteHandler.c.

References AccessShareLock, acquireLocksOnSubLinks(), AcquireRewriteLocks(), Assert, Query::cteList, CommonTableExpr::ctequery, elog, ERROR, acquireLocksOnSubLinks_context::for_execute, get_parse_rowmark(), get_rte_attribute_is_dropped(), Query::hasSubLinks, IsA, RangeTblEntry::joinaliasvars, lappend(), lfirst, NIL, NoLock, QTW_IGNORE_RC_SUBQUERIES, query_tree_walker(), RelationData::rd_rel, RangeTblEntry::relid, RangeTblEntry::relkind, RangeTblEntry::rellockmode, RowShareLock, rt_fetch, Query::rtable, RTE_JOIN, RTE_RELATION, RTE_SUBQUERY, RangeTblEntry::rtekind, strip_implicit_coercions(), RangeTblEntry::subquery, table_close(), table_open(), Var::varattno, Var::varlevelsup, and Var::varno.

Referenced by acquireLocksOnSubLinks(), AcquireRewriteLocks(), ApplyRetrieveRule(), get_query_def(), make_ruledef(), refresh_matview_datafill(), and rewriteRuleAction().

136 {
137  ListCell *l;
138  int rt_index;
140 
141  context.for_execute = forExecute;
142 
143  /*
144  * First, process RTEs of the current query level.
145  */
146  rt_index = 0;
147  foreach(l, parsetree->rtable)
148  {
149  RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
150  Relation rel;
151  LOCKMODE lockmode;
152  List *newaliasvars;
153  Index curinputvarno;
154  RangeTblEntry *curinputrte;
155  ListCell *ll;
156 
157  ++rt_index;
158  switch (rte->rtekind)
159  {
160  case RTE_RELATION:
161 
162  /*
163  * Grab the appropriate lock type for the relation, and do not
164  * release it until end of transaction. This protects the
165  * rewriter, planner, and executor against schema changes
166  * mid-query.
167  *
168  * If forExecute is false, ignore rellockmode and just use
169  * AccessShareLock.
170  */
171  if (!forExecute)
172  lockmode = AccessShareLock;
173  else if (forUpdatePushedDown)
174  {
175  /* Upgrade RTE's lock mode to reflect pushed-down lock */
176  if (rte->rellockmode == AccessShareLock)
177  rte->rellockmode = RowShareLock;
178  lockmode = rte->rellockmode;
179  }
180  else
181  lockmode = rte->rellockmode;
182 
183  rel = table_open(rte->relid, lockmode);
184 
185  /*
186  * While we have the relation open, update the RTE's relkind,
187  * just in case it changed since this rule was made.
188  */
189  rte->relkind = rel->rd_rel->relkind;
190 
191  table_close(rel, NoLock);
192  break;
193 
194  case RTE_JOIN:
195 
196  /*
197  * Scan the join's alias var list to see if any columns have
198  * been dropped, and if so replace those Vars with null
199  * pointers.
200  *
201  * Since a join has only two inputs, we can expect to see
202  * multiple references to the same input RTE; optimize away
203  * multiple fetches.
204  */
205  newaliasvars = NIL;
206  curinputvarno = 0;
207  curinputrte = NULL;
208  foreach(ll, rte->joinaliasvars)
209  {
210  Var *aliasitem = (Var *) lfirst(ll);
211  Var *aliasvar = aliasitem;
212 
213  /* Look through any implicit coercion */
214  aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
215 
216  /*
217  * If the list item isn't a simple Var, then it must
218  * represent a merged column, ie a USING column, and so it
219  * couldn't possibly be dropped, since it's referenced in
220  * the join clause. (Conceivably it could also be a null
221  * pointer already? But that's OK too.)
222  */
223  if (aliasvar && IsA(aliasvar, Var))
224  {
225  /*
226  * The elements of an alias list have to refer to
227  * earlier RTEs of the same rtable, because that's the
228  * order the planner builds things in. So we already
229  * processed the referenced RTE, and so it's safe to
230  * use get_rte_attribute_is_dropped on it. (This might
231  * not hold after rewriting or planning, but it's OK
232  * to assume here.)
233  */
234  Assert(aliasvar->varlevelsup == 0);
235  if (aliasvar->varno != curinputvarno)
236  {
237  curinputvarno = aliasvar->varno;
238  if (curinputvarno >= rt_index)
239  elog(ERROR, "unexpected varno %d in JOIN RTE %d",
240  curinputvarno, rt_index);
241  curinputrte = rt_fetch(curinputvarno,
242  parsetree->rtable);
243  }
244  if (get_rte_attribute_is_dropped(curinputrte,
245  aliasvar->varattno))
246  {
247  /* Replace the join alias item with a NULL */
248  aliasitem = NULL;
249  }
250  }
251  newaliasvars = lappend(newaliasvars, aliasitem);
252  }
253  rte->joinaliasvars = newaliasvars;
254  break;
255 
256  case RTE_SUBQUERY:
257 
258  /*
259  * The subquery RTE itself is all right, but we have to
260  * recurse to process the represented subquery.
261  */
263  forExecute,
264  (forUpdatePushedDown ||
265  get_parse_rowmark(parsetree, rt_index) != NULL));
266  break;
267 
268  default:
269  /* ignore other types of RTEs */
270  break;
271  }
272  }
273 
274  /* Recurse into subqueries in WITH */
275  foreach(l, parsetree->cteList)
276  {
277  CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
278 
279  AcquireRewriteLocks((Query *) cte->ctequery, forExecute, false);
280  }
281 
282  /*
283  * Recurse into sublink subqueries, too. But we already did the ones in
284  * the rtable and cteList.
285  */
286  if (parsetree->hasSubLinks)
287  query_tree_walker(parsetree, acquireLocksOnSubLinks, &context,
289 }
#define NIL
Definition: pg_list.h:65
bool query_tree_walker(Query *query, bool(*walker)(), void *context, int flags)
Definition: nodeFuncs.c:2273
#define IsA(nodeptr, _type_)
Definition: nodes.h:580
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:133
List * joinaliasvars
Definition: parsenodes.h:1051
Index varlevelsup
Definition: primnodes.h:191
RowMarkClause * get_parse_rowmark(Query *qry, Index rtindex)
static bool acquireLocksOnSubLinks(Node *node, acquireLocksOnSubLinks_context *context)
int LOCKMODE
Definition: lockdefs.h:26
#define AccessShareLock
Definition: lockdefs.h:36
Definition: nodes.h:529
AttrNumber varattno
Definition: primnodes.h:186
Form_pg_class rd_rel
Definition: rel.h:109
Definition: primnodes.h:181
#define QTW_IGNORE_RC_SUBQUERIES
Definition: nodeFuncs.h:22
List * rtable
Definition: parsenodes.h:137
#define ERROR
Definition: elog.h:43
#define NoLock
Definition: lockdefs.h:34
void AcquireRewriteLocks(Query *parsetree, bool forExecute, bool forUpdatePushedDown)
#define rt_fetch(rangetable_index, rangetable)
Definition: parsetree.h:31
List * lappend(List *list, void *datum)
Definition: list.c:321
Index varno
Definition: primnodes.h:184
#define RowShareLock
Definition: lockdefs.h:37
bool get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
unsigned int Index
Definition: c.h:482
#define Assert(condition)
Definition: c.h:745
#define lfirst(lc)
Definition: pg_list.h:190
RTEKind rtekind
Definition: parsenodes.h:976
List * cteList
Definition: parsenodes.h:135
Query * subquery
Definition: parsenodes.h:1011
bool hasSubLinks
Definition: parsenodes.h:128
#define elog(elevel,...)
Definition: elog.h:214
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
Definition: pg_list.h:50
Node * strip_implicit_coercions(Node *node)
Definition: nodeFuncs.c:611

◆ build_column_default()

Node* build_column_default ( Relation  rel,
int  attrno 
)

Definition at line 1123 of file rewriteHandler.c.

References COERCE_IMPLICIT_CAST, coerce_to_target_type(), COERCION_ASSIGNMENT, TupleDescData::constr, TupleConstr::defval, ereport, errcode(), errhint(), errmsg(), ERROR, exprType(), format_type_be(), get_typdefault(), getIdentitySequence(), makeNode, NameStr, TupleConstr::num_defval, RelationData::rd_att, RelationGetRelid, NextValueExpr::seqid, stringToNode(), TupleDescAttr, and NextValueExpr::typeId.

Referenced by ATExecAddColumn(), ATExecAlterColumnType(), BeginCopyFrom(), ExecComputeStoredGenerated(), rewriteTargetListIU(), rewriteValuesRTE(), and slot_fill_defaults().

1124 {
1125  TupleDesc rd_att = rel->rd_att;
1126  Form_pg_attribute att_tup = TupleDescAttr(rd_att, attrno - 1);
1127  Oid atttype = att_tup->atttypid;
1128  int32 atttypmod = att_tup->atttypmod;
1129  Node *expr = NULL;
1130  Oid exprtype;
1131 
1132  if (att_tup->attidentity)
1133  {
1135 
1136  nve->seqid = getIdentitySequence(RelationGetRelid(rel), attrno, false);
1137  nve->typeId = att_tup->atttypid;
1138 
1139  return (Node *) nve;
1140  }
1141 
1142  /*
1143  * Scan to see if relation has a default for this column.
1144  */
1145  if (att_tup->atthasdef && rd_att->constr &&
1146  rd_att->constr->num_defval > 0)
1147  {
1148  AttrDefault *defval = rd_att->constr->defval;
1149  int ndef = rd_att->constr->num_defval;
1150 
1151  while (--ndef >= 0)
1152  {
1153  if (attrno == defval[ndef].adnum)
1154  {
1155  /*
1156  * Found it, convert string representation to node tree.
1157  */
1158  expr = stringToNode(defval[ndef].adbin);
1159  break;
1160  }
1161  }
1162  }
1163 
1164  /*
1165  * No per-column default, so look for a default for the type itself. But
1166  * not for generated columns.
1167  */
1168  if (expr == NULL && !att_tup->attgenerated)
1169  expr = get_typdefault(atttype);
1170 
1171  if (expr == NULL)
1172  return NULL; /* No default anywhere */
1173 
1174  /*
1175  * Make sure the value is coerced to the target column type; this will
1176  * generally be true already, but there seem to be some corner cases
1177  * involving domain defaults where it might not be true. This should match
1178  * the parser's processing of non-defaulted expressions --- see
1179  * transformAssignedExpr().
1180  */
1181  exprtype = exprType(expr);
1182 
1183  expr = coerce_to_target_type(NULL, /* no UNKNOWN params here */
1184  expr, exprtype,
1185  atttype, atttypmod,
1188  -1);
1189  if (expr == NULL)
1190  ereport(ERROR,
1191  (errcode(ERRCODE_DATATYPE_MISMATCH),
1192  errmsg("column \"%s\" is of type %s"
1193  " but default expression is of type %s",
1194  NameStr(att_tup->attname),
1195  format_type_be(atttype),
1196  format_type_be(exprtype)),
1197  errhint("You will need to rewrite or cast the expression.")));
1198 
1199  return expr;
1200 }
int errhint(const char *fmt,...)
Definition: elog.c:1071
#define TupleDescAttr(tupdesc, i)
Definition: tupdesc.h:92
Definition: nodes.h:529
int errcode(int sqlerrcode)
Definition: elog.c:610
void * stringToNode(const char *str)
Definition: read.c:89
char * format_type_be(Oid type_oid)
Definition: format_type.c:339
unsigned int Oid
Definition: postgres_ext.h:31
Oid getIdentitySequence(Oid relid, AttrNumber attnum, bool missing_ok)
Definition: pg_depend.c:872
signed int int32
Definition: c.h:362
AttrDefault * defval
Definition: tupdesc.h:39
#define ERROR
Definition: elog.h:43
Node * coerce_to_target_type(ParseState *pstate, Node *expr, Oid exprtype, Oid targettype, int32 targettypmod, CoercionContext ccontext, CoercionForm cformat, int location)
Definition: parse_coerce.c:77
TupleConstr * constr
Definition: tupdesc.h:85
FormData_pg_attribute * Form_pg_attribute
Definition: pg_attribute.h:193
TupleDesc rd_att
Definition: rel.h:110
#define ereport(elevel,...)
Definition: elog.h:144
#define makeNode(_type_)
Definition: nodes.h:577
Node * get_typdefault(Oid typid)
Definition: lsyscache.c:2336
Oid exprType(const Node *expr)
Definition: nodeFuncs.c:41
uint16 num_defval
Definition: tupdesc.h:42
int errmsg(const char *fmt,...)
Definition: elog.c:824
#define NameStr(name)
Definition: c.h:622
#define RelationGetRelid(relation)
Definition: rel.h:456

◆ get_view_query()

Query* get_view_query ( Relation  view)

Definition at line 2297 of file rewriteHandler.c.

References RewriteRule::actions, Assert, CMD_SELECT, elog, ERROR, RewriteRule::event, i, linitial, list_length(), RuleLock::numLocks, RelationData::rd_rel, RelationData::rd_rules, and RuleLock::rules.

Referenced by ATExecSetRelOptions(), LockViewRecurse(), relation_is_updatable(), and rewriteTargetView().

2298 {
2299  int i;
2300 
2301  Assert(view->rd_rel->relkind == RELKIND_VIEW);
2302 
2303  for (i = 0; i < view->rd_rules->numLocks; i++)
2304  {
2305  RewriteRule *rule = view->rd_rules->rules[i];
2306 
2307  if (rule->event == CMD_SELECT)
2308  {
2309  /* A _RETURN rule should have only one action */
2310  if (list_length(rule->actions) != 1)
2311  elog(ERROR, "invalid _RETURN rule action specification");
2312 
2313  return (Query *) linitial(rule->actions);
2314  }
2315  }
2316 
2317  elog(ERROR, "failed to find _RETURN rule for view");
2318  return NULL; /* keep compiler quiet */
2319 }
int numLocks
Definition: prs2lock.h:42
Form_pg_class rd_rel
Definition: rel.h:109
Definition: localtime.c:72
#define linitial(l)
Definition: pg_list.h:195
#define ERROR
Definition: elog.h:43
CmdType event
Definition: prs2lock.h:27
RewriteRule ** rules
Definition: prs2lock.h:43
List * actions
Definition: prs2lock.h:29
#define Assert(condition)
Definition: c.h:745
RuleLock * rd_rules
Definition: rel.h:113
static int list_length(const List *l)
Definition: pg_list.h:169
#define elog(elevel,...)
Definition: elog.h:214
int i

◆ QueryRewrite()

List* QueryRewrite ( Query parsetree)

Definition at line 3927 of file rewriteHandler.c.

References Assert, Query::canSetTag, Query::commandType, fireRIRrules(), lappend(), lfirst, NIL, QSRC_INSTEAD_RULE, QSRC_ORIGINAL, QSRC_QUAL_INSTEAD_RULE, Query::queryId, Query::querySource, and RewriteQuery().

Referenced by ExecCreateTableAs(), ExplainOneUtility(), ExplainQuery(), PerformCursorOpen(), pg_rewrite_query(), PrepareQuery(), and refresh_matview_datafill().

3928 {
3929  uint64 input_query_id = parsetree->queryId;
3930  List *querylist;
3931  List *results;
3932  ListCell *l;
3933  CmdType origCmdType;
3934  bool foundOriginalQuery;
3935  Query *lastInstead;
3936 
3937  /*
3938  * This function is only applied to top-level original queries
3939  */
3940  Assert(parsetree->querySource == QSRC_ORIGINAL);
3941  Assert(parsetree->canSetTag);
3942 
3943  /*
3944  * Step 1
3945  *
3946  * Apply all non-SELECT rules possibly getting 0 or many queries
3947  */
3948  querylist = RewriteQuery(parsetree, NIL);
3949 
3950  /*
3951  * Step 2
3952  *
3953  * Apply all the RIR rules on each query
3954  *
3955  * This is also a handy place to mark each query with the original queryId
3956  */
3957  results = NIL;
3958  foreach(l, querylist)
3959  {
3960  Query *query = (Query *) lfirst(l);
3961 
3962  query = fireRIRrules(query, NIL);
3963 
3964  query->queryId = input_query_id;
3965 
3966  results = lappend(results, query);
3967  }
3968 
3969  /*
3970  * Step 3
3971  *
3972  * Determine which, if any, of the resulting queries is supposed to set
3973  * the command-result tag; and update the canSetTag fields accordingly.
3974  *
3975  * If the original query is still in the list, it sets the command tag.
3976  * Otherwise, the last INSTEAD query of the same kind as the original is
3977  * allowed to set the tag. (Note these rules can leave us with no query
3978  * setting the tag. The tcop code has to cope with this by setting up a
3979  * default tag based on the original un-rewritten query.)
3980  *
3981  * The Asserts verify that at most one query in the result list is marked
3982  * canSetTag. If we aren't checking asserts, we can fall out of the loop
3983  * as soon as we find the original query.
3984  */
3985  origCmdType = parsetree->commandType;
3986  foundOriginalQuery = false;
3987  lastInstead = NULL;
3988 
3989  foreach(l, results)
3990  {
3991  Query *query = (Query *) lfirst(l);
3992 
3993  if (query->querySource == QSRC_ORIGINAL)
3994  {
3995  Assert(query->canSetTag);
3996  Assert(!foundOriginalQuery);
3997  foundOriginalQuery = true;
3998 #ifndef USE_ASSERT_CHECKING
3999  break;
4000 #endif
4001  }
4002  else
4003  {
4004  Assert(!query->canSetTag);
4005  if (query->commandType == origCmdType &&
4006  (query->querySource == QSRC_INSTEAD_RULE ||
4008  lastInstead = query;
4009  }
4010  }
4011 
4012  if (!foundOriginalQuery && lastInstead != NULL)
4013  lastInstead->canSetTag = true;
4014 
4015  return results;
4016 }
#define NIL
Definition: pg_list.h:65
static List * RewriteQuery(Query *parsetree, List *rewrite_events)
List * lappend(List *list, void *datum)
Definition: list.c:321
uint64 queryId
Definition: parsenodes.h:116
CmdType commandType
Definition: parsenodes.h:112
QuerySource querySource
Definition: parsenodes.h:114
#define Assert(condition)
Definition: c.h:745
#define lfirst(lc)
Definition: pg_list.h:190
bool canSetTag
Definition: parsenodes.h:118
static Query * fireRIRrules(Query *parsetree, List *activeRIRs)
Definition: pg_list.h:50
CmdType
Definition: nodes.h:672

◆ relation_is_updatable()

int relation_is_updatable ( Oid  reloid,
List outer_reloids,
bool  include_triggers,
Bitmapset include_cols 
)

Definition at line 2647 of file rewriteHandler.c.

References AccessShareLock, adjust_view_column_set(), ALL_EVENTS, Assert, bms_int_members(), bms_is_empty(), check_stack_depth(), CMD_DELETE, CMD_INSERT, CMD_UPDATE, RewriteRule::event, FdwRoutine::ExecForeignDelete, FdwRoutine::ExecForeignInsert, FdwRoutine::ExecForeignUpdate, FromExpr::fromlist, get_view_query(), GetFdwRoutineForRelation(), i, FdwRoutine::IsForeignRelUpdatable, RewriteRule::isInstead, Query::jointree, lappend_oid(), linitial, list_delete_last(), list_member_oid(), RuleLock::numLocks, RewriteRule::qual, RelationData::rd_rel, RelationData::rd_rules, relation_close(), relation_is_updatable(), RelationGetRelid, RangeTblEntry::relid, RangeTblEntry::relkind, rt_fetch, Query::rtable, RTE_RELATION, RangeTblEntry::rtekind, RangeTblRef::rtindex, RuleLock::rules, Query::targetList, TriggerDesc::trig_delete_instead_row, TriggerDesc::trig_insert_instead_row, TriggerDesc::trig_update_instead_row, RelationData::trigdesc, try_relation_open(), view_cols_are_auto_updatable(), and view_query_is_auto_updatable().

Referenced by pg_column_is_updatable(), pg_relation_is_updatable(), and relation_is_updatable().

2651 {
2652  int events = 0;
2653  Relation rel;
2654  RuleLock *rulelocks;
2655 
2656 #define ALL_EVENTS ((1 << CMD_INSERT) | (1 << CMD_UPDATE) | (1 << CMD_DELETE))
2657 
2658  /* Since this function recurses, it could be driven to stack overflow */
2660 
2661  rel = try_relation_open(reloid, AccessShareLock);
2662 
2663  /*
2664  * If the relation doesn't exist, return zero rather than throwing an
2665  * error. This is helpful since scanning an information_schema view under
2666  * MVCC rules can result in referencing rels that have actually been
2667  * deleted already.
2668  */
2669  if (rel == NULL)
2670  return 0;
2671 
2672  /* If we detect a recursive view, report that it is not updatable */
2673  if (list_member_oid(outer_reloids, RelationGetRelid(rel)))
2674  {
2676  return 0;
2677  }
2678 
2679  /* If the relation is a table, it is always updatable */
2680  if (rel->rd_rel->relkind == RELKIND_RELATION ||
2681  rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
2682  {
2684  return ALL_EVENTS;
2685  }
2686 
2687  /* Look for unconditional DO INSTEAD rules, and note supported events */
2688  rulelocks = rel->rd_rules;
2689  if (rulelocks != NULL)
2690  {
2691  int i;
2692 
2693  for (i = 0; i < rulelocks->numLocks; i++)
2694  {
2695  if (rulelocks->rules[i]->isInstead &&
2696  rulelocks->rules[i]->qual == NULL)
2697  {
2698  events |= ((1 << rulelocks->rules[i]->event) & ALL_EVENTS);
2699  }
2700  }
2701 
2702  /* If we have rules for all events, we're done */
2703  if (events == ALL_EVENTS)
2704  {
2706  return events;
2707  }
2708  }
2709 
2710  /* Similarly look for INSTEAD OF triggers, if they are to be included */
2711  if (include_triggers)
2712  {
2713  TriggerDesc *trigDesc = rel->trigdesc;
2714 
2715  if (trigDesc)
2716  {
2717  if (trigDesc->trig_insert_instead_row)
2718  events |= (1 << CMD_INSERT);
2719  if (trigDesc->trig_update_instead_row)
2720  events |= (1 << CMD_UPDATE);
2721  if (trigDesc->trig_delete_instead_row)
2722  events |= (1 << CMD_DELETE);
2723 
2724  /* If we have triggers for all events, we're done */
2725  if (events == ALL_EVENTS)
2726  {
2728  return events;
2729  }
2730  }
2731  }
2732 
2733  /* If this is a foreign table, check which update events it supports */
2734  if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
2735  {
2736  FdwRoutine *fdwroutine = GetFdwRoutineForRelation(rel, false);
2737 
2738  if (fdwroutine->IsForeignRelUpdatable != NULL)
2739  events |= fdwroutine->IsForeignRelUpdatable(rel);
2740  else
2741  {
2742  /* Assume presence of executor functions is sufficient */
2743  if (fdwroutine->ExecForeignInsert != NULL)
2744  events |= (1 << CMD_INSERT);
2745  if (fdwroutine->ExecForeignUpdate != NULL)
2746  events |= (1 << CMD_UPDATE);
2747  if (fdwroutine->ExecForeignDelete != NULL)
2748  events |= (1 << CMD_DELETE);
2749  }
2750 
2752  return events;
2753  }
2754 
2755  /* Check if this is an automatically updatable view */
2756  if (rel->rd_rel->relkind == RELKIND_VIEW)
2757  {
2758  Query *viewquery = get_view_query(rel);
2759 
2760  if (view_query_is_auto_updatable(viewquery, false) == NULL)
2761  {
2762  Bitmapset *updatable_cols;
2763  int auto_events;
2764  RangeTblRef *rtr;
2765  RangeTblEntry *base_rte;
2766  Oid baseoid;
2767 
2768  /*
2769  * Determine which of the view's columns are updatable. If there
2770  * are none within the set of columns we are looking at, then the
2771  * view doesn't support INSERT/UPDATE, but it may still support
2772  * DELETE.
2773  */
2774  view_cols_are_auto_updatable(viewquery, NULL,
2775  &updatable_cols, NULL);
2776 
2777  if (include_cols != NULL)
2778  updatable_cols = bms_int_members(updatable_cols, include_cols);
2779 
2780  if (bms_is_empty(updatable_cols))
2781  auto_events = (1 << CMD_DELETE); /* May support DELETE */
2782  else
2783  auto_events = ALL_EVENTS; /* May support all events */
2784 
2785  /*
2786  * The base relation must also support these update commands.
2787  * Tables are always updatable, but for any other kind of base
2788  * relation we must do a recursive check limited to the columns
2789  * referenced by the locally updatable columns in this view.
2790  */
2791  rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
2792  base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
2793  Assert(base_rte->rtekind == RTE_RELATION);
2794 
2795  if (base_rte->relkind != RELKIND_RELATION &&
2796  base_rte->relkind != RELKIND_PARTITIONED_TABLE)
2797  {
2798  baseoid = base_rte->relid;
2799  outer_reloids = lappend_oid(outer_reloids,
2800  RelationGetRelid(rel));
2801  include_cols = adjust_view_column_set(updatable_cols,
2802  viewquery->targetList);
2803  auto_events &= relation_is_updatable(baseoid,
2804  outer_reloids,
2805  include_triggers,
2806  include_cols);
2807  outer_reloids = list_delete_last(outer_reloids);
2808  }
2809  events |= auto_events;
2810  }
2811  }
2812 
2813  /* If we reach here, the relation may support some update commands */
2815  return events;
2816 }
ExecForeignDelete_function ExecForeignDelete
Definition: fdwapi.h:213
Node * qual
Definition: prs2lock.h:28
int numLocks
Definition: prs2lock.h:42
FromExpr * jointree
Definition: parsenodes.h:138
ExecForeignInsert_function ExecForeignInsert
Definition: fdwapi.h:211
static const char * view_cols_are_auto_updatable(Query *viewquery, Bitmapset *required_cols, Bitmapset **updatable_cols, char **non_updatable_col)
#define AccessShareLock
Definition: lockdefs.h:36
List * fromlist
Definition: primnodes.h:1510
Form_pg_class rd_rel
Definition: rel.h:109
unsigned int Oid
Definition: postgres_ext.h:31
List * lappend_oid(List *list, Oid datum)
Definition: list.c:357
bool isInstead
Definition: prs2lock.h:31
Relation try_relation_open(Oid relationId, LOCKMODE lockmode)
Definition: relation.c:89
List * targetList
Definition: parsenodes.h:140
bool trig_insert_instead_row
Definition: reltrigger.h:58
#define linitial(l)
Definition: pg_list.h:195
List * rtable
Definition: parsenodes.h:137
#define ALL_EVENTS
TriggerDesc * trigdesc
Definition: rel.h:115
void check_stack_depth(void)
Definition: postgres.c:3312
CmdType event
Definition: prs2lock.h:27
List * list_delete_last(List *list)
Definition: list.c:877
RewriteRule ** rules
Definition: prs2lock.h:43
#define rt_fetch(rangetable_index, rangetable)
Definition: parsetree.h:31
int relation_is_updatable(Oid reloid, List *outer_reloids, bool include_triggers, Bitmapset *include_cols)
bool trig_update_instead_row
Definition: reltrigger.h:63
bool bms_is_empty(const Bitmapset *a)
Definition: bitmapset.c:701
bool trig_delete_instead_row
Definition: reltrigger.h:68
static Bitmapset * adjust_view_column_set(Bitmapset *cols, List *targetlist)
ExecForeignUpdate_function ExecForeignUpdate
Definition: fdwapi.h:212
bool list_member_oid(const List *list, Oid datum)
Definition: list.c:674
void relation_close(Relation relation, LOCKMODE lockmode)
Definition: relation.c:206
#define Assert(condition)
Definition: c.h:745
RuleLock * rd_rules
Definition: rel.h:113
RTEKind rtekind
Definition: parsenodes.h:976
FdwRoutine * GetFdwRoutineForRelation(Relation relation, bool makecopy)
Definition: foreign.c:427
Query * get_view_query(Relation view)
int i
IsForeignRelUpdatable_function IsForeignRelUpdatable
Definition: fdwapi.h:217
Bitmapset * bms_int_members(Bitmapset *a, const Bitmapset *b)
Definition: bitmapset.c:902
const char * view_query_is_auto_updatable(Query *viewquery, bool check_cols)
#define RelationGetRelid(relation)
Definition: rel.h:456

◆ rewriteTargetListUD()

void rewriteTargetListUD ( Query parsetree,
RangeTblEntry target_rte,
Relation  target_relation 
)

Definition at line 1446 of file rewriteHandler.c.

References FdwRoutine::AddForeignUpdateTargets, CMD_DELETE, CMD_UPDATE, Query::commandType, GetFdwRoutineForRelation(), InvalidOid, lappend(), list_length(), makeTargetEntry(), makeVar(), makeWholeRowVar(), pstrdup(), RelationData::rd_rel, Query::resultRelation, SelfItemPointerAttributeNumber, Query::targetList, TriggerDesc::trig_delete_after_row, TriggerDesc::trig_delete_before_row, TriggerDesc::trig_update_after_row, TriggerDesc::trig_update_before_row, and RelationData::trigdesc.

Referenced by preprocess_targetlist().

1448 {
1449  Var *var = NULL;
1450  const char *attrname;
1451  TargetEntry *tle;
1452 
1453  if (target_relation->rd_rel->relkind == RELKIND_RELATION ||
1454  target_relation->rd_rel->relkind == RELKIND_MATVIEW ||
1455  target_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
1456  {
1457  /*
1458  * Emit CTID so that executor can find the row to update or delete.
1459  */
1460  var = makeVar(parsetree->resultRelation,
1462  TIDOID,
1463  -1,
1464  InvalidOid,
1465  0);
1466 
1467  attrname = "ctid";
1468  }
1469  else if (target_relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
1470  {
1471  /*
1472  * Let the foreign table's FDW add whatever junk TLEs it wants.
1473  */
1474  FdwRoutine *fdwroutine;
1475 
1476  fdwroutine = GetFdwRoutineForRelation(target_relation, false);
1477 
1478  if (fdwroutine->AddForeignUpdateTargets != NULL)
1479  fdwroutine->AddForeignUpdateTargets(parsetree, target_rte,
1480  target_relation);
1481 
1482  /*
1483  * If we have a row-level trigger corresponding to the operation, emit
1484  * a whole-row Var so that executor will have the "old" row to pass to
1485  * the trigger. Alas, this misses system columns.
1486  */
1487  if (target_relation->trigdesc &&
1488  ((parsetree->commandType == CMD_UPDATE &&
1489  (target_relation->trigdesc->trig_update_after_row ||
1490  target_relation->trigdesc->trig_update_before_row)) ||
1491  (parsetree->commandType == CMD_DELETE &&
1492  (target_relation->trigdesc->trig_delete_after_row ||
1493  target_relation->trigdesc->trig_delete_before_row))))
1494  {
1495  var = makeWholeRowVar(target_rte,
1496  parsetree->resultRelation,
1497  0,
1498  false);
1499 
1500  attrname = "wholerow";
1501  }
1502  }
1503 
1504  if (var != NULL)
1505  {
1506  tle = makeTargetEntry((Expr *) var,
1507  list_length(parsetree->targetList) + 1,
1508  pstrdup(attrname),
1509  true);
1510 
1511  parsetree->targetList = lappend(parsetree->targetList, tle);
1512  }
1513 }
char * pstrdup(const char *in)
Definition: mcxt.c:1186
int resultRelation
Definition: parsenodes.h:122
Var * makeWholeRowVar(RangeTblEntry *rte, Index varno, Index varlevelsup, bool allowScalar)
Definition: makefuncs.c:133
Form_pg_class rd_rel
Definition: rel.h:109
Definition: primnodes.h:181
AddForeignUpdateTargets_function AddForeignUpdateTargets
Definition: fdwapi.h:208
List * targetList
Definition: parsenodes.h:140
TriggerDesc * trigdesc
Definition: rel.h:115
bool trig_delete_after_row
Definition: reltrigger.h:67
bool trig_update_before_row
Definition: reltrigger.h:61
TargetEntry * makeTargetEntry(Expr *expr, AttrNumber resno, char *resname, bool resjunk)
Definition: makefuncs.c:238
Var * makeVar(Index varno, AttrNumber varattno, Oid vartype, int32 vartypmod, Oid varcollid, Index varlevelsup)
Definition: makefuncs.c:66
bool trig_update_after_row
Definition: reltrigger.h:62
List * lappend(List *list, void *datum)
Definition: list.c:321
#define InvalidOid
Definition: postgres_ext.h:36
CmdType commandType
Definition: parsenodes.h:112
static int list_length(const List *l)
Definition: pg_list.h:169
FdwRoutine * GetFdwRoutineForRelation(Relation relation, bool makecopy)
Definition: foreign.c:427
#define SelfItemPointerAttributeNumber
Definition: sysattr.h:21
bool trig_delete_before_row
Definition: reltrigger.h:66

◆ view_query_is_auto_updatable()

const char* view_query_is_auto_updatable ( Query viewquery,
bool  check_cols 
)

Definition at line 2416 of file rewriteHandler.c.

References Query::cteList, Query::distinctClause, FromExpr::fromlist, gettext_noop, Query::groupClause, Query::groupingSets, Query::hasAggs, Query::hasTargetSRFs, Query::hasWindowFuncs, Query::havingQual, IsA, Query::jointree, lfirst, Query::limitCount, Query::limitOffset, linitial, list_length(), NIL, RangeTblEntry::relkind, rt_fetch, Query::rtable, RTE_RELATION, RangeTblEntry::rtekind, RangeTblRef::rtindex, Query::setOperations, RangeTblEntry::tablesample, Query::targetList, and view_col_is_auto_updatable().

Referenced by ATExecSetRelOptions(), DefineView(), relation_is_updatable(), and rewriteTargetView().

2417 {
2418  RangeTblRef *rtr;
2419  RangeTblEntry *base_rte;
2420 
2421  /*----------
2422  * Check if the view is simply updatable. According to SQL-92 this means:
2423  * - No DISTINCT clause.
2424  * - Each TLE is a column reference, and each column appears at most once.
2425  * - FROM contains exactly one base relation.
2426  * - No GROUP BY or HAVING clauses.
2427  * - No set operations (UNION, INTERSECT or EXCEPT).
2428  * - No sub-queries in the WHERE clause that reference the target table.
2429  *
2430  * We ignore that last restriction since it would be complex to enforce
2431  * and there isn't any actual benefit to disallowing sub-queries. (The
2432  * semantic issues that the standard is presumably concerned about don't
2433  * arise in Postgres, since any such sub-query will not see any updates
2434  * executed by the outer query anyway, thanks to MVCC snapshotting.)
2435  *
2436  * We also relax the second restriction by supporting part of SQL:1999
2437  * feature T111, which allows for a mix of updatable and non-updatable
2438  * columns, provided that an INSERT or UPDATE doesn't attempt to assign to
2439  * a non-updatable column.
2440  *
2441  * In addition we impose these constraints, involving features that are
2442  * not part of SQL-92:
2443  * - No CTEs (WITH clauses).
2444  * - No OFFSET or LIMIT clauses (this matches a SQL:2008 restriction).
2445  * - No system columns (including whole-row references) in the tlist.
2446  * - No window functions in the tlist.
2447  * - No set-returning functions in the tlist.
2448  *
2449  * Note that we do these checks without recursively expanding the view.
2450  * If the base relation is a view, we'll recursively deal with it later.
2451  *----------
2452  */
2453  if (viewquery->distinctClause != NIL)
2454  return gettext_noop("Views containing DISTINCT are not automatically updatable.");
2455 
2456  if (viewquery->groupClause != NIL || viewquery->groupingSets)
2457  return gettext_noop("Views containing GROUP BY are not automatically updatable.");
2458 
2459  if (viewquery->havingQual != NULL)
2460  return gettext_noop("Views containing HAVING are not automatically updatable.");
2461 
2462  if (viewquery->setOperations != NULL)
2463  return gettext_noop("Views containing UNION, INTERSECT, or EXCEPT are not automatically updatable.");
2464 
2465  if (viewquery->cteList != NIL)
2466  return gettext_noop("Views containing WITH are not automatically updatable.");
2467 
2468  if (viewquery->limitOffset != NULL || viewquery->limitCount != NULL)
2469  return gettext_noop("Views containing LIMIT or OFFSET are not automatically updatable.");
2470 
2471  /*
2472  * We must not allow window functions or set returning functions in the
2473  * targetlist. Otherwise we might end up inserting them into the quals of
2474  * the main query. We must also check for aggregates in the targetlist in
2475  * case they appear without a GROUP BY.
2476  *
2477  * These restrictions ensure that each row of the view corresponds to a
2478  * unique row in the underlying base relation.
2479  */
2480  if (viewquery->hasAggs)
2481  return gettext_noop("Views that return aggregate functions are not automatically updatable.");
2482 
2483  if (viewquery->hasWindowFuncs)
2484  return gettext_noop("Views that return window functions are not automatically updatable.");
2485 
2486  if (viewquery->hasTargetSRFs)
2487  return gettext_noop("Views that return set-returning functions are not automatically updatable.");
2488 
2489  /*
2490  * The view query should select from a single base relation, which must be
2491  * a table or another view.
2492  */
2493  if (list_length(viewquery->jointree->fromlist) != 1)
2494  return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2495 
2496  rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
2497  if (!IsA(rtr, RangeTblRef))
2498  return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2499 
2500  base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
2501  if (base_rte->rtekind != RTE_RELATION ||
2502  (base_rte->relkind != RELKIND_RELATION &&
2503  base_rte->relkind != RELKIND_FOREIGN_TABLE &&
2504  base_rte->relkind != RELKIND_VIEW &&
2505  base_rte->relkind != RELKIND_PARTITIONED_TABLE))
2506  return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2507 
2508  if (base_rte->tablesample)
2509  return gettext_noop("Views containing TABLESAMPLE are not automatically updatable.");
2510 
2511  /*
2512  * Check that the view has at least one updatable column. This is required
2513  * for INSERT/UPDATE but not for DELETE.
2514  */
2515  if (check_cols)
2516  {
2517  ListCell *cell;
2518  bool found;
2519 
2520  found = false;
2521  foreach(cell, viewquery->targetList)
2522  {
2523  TargetEntry *tle = (TargetEntry *) lfirst(cell);
2524 
2525  if (view_col_is_auto_updatable(rtr, tle) == NULL)
2526  {
2527  found = true;
2528  break;
2529  }
2530  }
2531 
2532  if (!found)
2533  return gettext_noop("Views that have no updatable columns are not automatically updatable.");
2534  }
2535 
2536  return NULL; /* the view is updatable */
2537 }
Node * limitOffset
Definition: parsenodes.h:160
#define NIL
Definition: pg_list.h:65
#define IsA(nodeptr, _type_)
Definition: nodes.h:580
FromExpr * jointree
Definition: parsenodes.h:138
bool hasAggs
Definition: parsenodes.h:125
List * groupingSets
Definition: parsenodes.h:150
#define gettext_noop(x)
Definition: c.h:1166
List * fromlist
Definition: primnodes.h:1510
List * targetList
Definition: parsenodes.h:140
#define linitial(l)
Definition: pg_list.h:195
List * rtable
Definition: parsenodes.h:137
List * distinctClause
Definition: parsenodes.h:156
Node * limitCount
Definition: parsenodes.h:161
#define rt_fetch(rangetable_index, rangetable)
Definition: parsetree.h:31
bool hasTargetSRFs
Definition: parsenodes.h:127
#define lfirst(lc)
Definition: pg_list.h:190
bool hasWindowFuncs
Definition: parsenodes.h:126
static int list_length(const List *l)
Definition: pg_list.h:169
RTEKind rtekind
Definition: parsenodes.h:976
List * cteList
Definition: parsenodes.h:135
Node * setOperations
Definition: parsenodes.h:166
List * groupClause
Definition: parsenodes.h:148
static const char * view_col_is_auto_updatable(RangeTblRef *rtr, TargetEntry *tle)
Node * havingQual
Definition: parsenodes.h:152
struct TableSampleClause * tablesample
Definition: parsenodes.h:1006