PostgreSQL Source Code  git master
rewriteHandler.h File Reference
#include "utils/relcache.h"
#include "nodes/parsenodes.h"
Include dependency graph for rewriteHandler.h:
This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

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, bool include_triggers, Bitmapset *include_cols)
 

Function Documentation

◆ AcquireRewriteLocks()

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

Definition at line 132 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().

135 {
136  ListCell *l;
137  int rt_index;
139 
140  context.for_execute = forExecute;
141 
142  /*
143  * First, process RTEs of the current query level.
144  */
145  rt_index = 0;
146  foreach(l, parsetree->rtable)
147  {
148  RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
149  Relation rel;
150  LOCKMODE lockmode;
151  List *newaliasvars;
152  Index curinputvarno;
153  RangeTblEntry *curinputrte;
154  ListCell *ll;
155 
156  ++rt_index;
157  switch (rte->rtekind)
158  {
159  case RTE_RELATION:
160 
161  /*
162  * Grab the appropriate lock type for the relation, and do not
163  * release it until end of transaction. This protects the
164  * rewriter, planner, and executor against schema changes
165  * mid-query.
166  *
167  * If forExecute is false, ignore rellockmode and just use
168  * AccessShareLock.
169  */
170  if (!forExecute)
171  lockmode = AccessShareLock;
172  else if (forUpdatePushedDown)
173  {
174  /* Upgrade RTE's lock mode to reflect pushed-down lock */
175  if (rte->rellockmode == AccessShareLock)
176  rte->rellockmode = RowShareLock;
177  lockmode = rte->rellockmode;
178  }
179  else
180  lockmode = rte->rellockmode;
181 
182  rel = table_open(rte->relid, lockmode);
183 
184  /*
185  * While we have the relation open, update the RTE's relkind,
186  * just in case it changed since this rule was made.
187  */
188  rte->relkind = rel->rd_rel->relkind;
189 
190  table_close(rel, NoLock);
191  break;
192 
193  case RTE_JOIN:
194 
195  /*
196  * Scan the join's alias var list to see if any columns have
197  * been dropped, and if so replace those Vars with null
198  * pointers.
199  *
200  * Since a join has only two inputs, we can expect to see
201  * multiple references to the same input RTE; optimize away
202  * multiple fetches.
203  */
204  newaliasvars = NIL;
205  curinputvarno = 0;
206  curinputrte = NULL;
207  foreach(ll, rte->joinaliasvars)
208  {
209  Var *aliasitem = (Var *) lfirst(ll);
210  Var *aliasvar = aliasitem;
211 
212  /* Look through any implicit coercion */
213  aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
214 
215  /*
216  * If the list item isn't a simple Var, then it must
217  * represent a merged column, ie a USING column, and so it
218  * couldn't possibly be dropped, since it's referenced in
219  * the join clause. (Conceivably it could also be a null
220  * pointer already? But that's OK too.)
221  */
222  if (aliasvar && IsA(aliasvar, Var))
223  {
224  /*
225  * The elements of an alias list have to refer to
226  * earlier RTEs of the same rtable, because that's the
227  * order the planner builds things in. So we already
228  * processed the referenced RTE, and so it's safe to
229  * use get_rte_attribute_is_dropped on it. (This might
230  * not hold after rewriting or planning, but it's OK
231  * to assume here.)
232  */
233  Assert(aliasvar->varlevelsup == 0);
234  if (aliasvar->varno != curinputvarno)
235  {
236  curinputvarno = aliasvar->varno;
237  if (curinputvarno >= rt_index)
238  elog(ERROR, "unexpected varno %d in JOIN RTE %d",
239  curinputvarno, rt_index);
240  curinputrte = rt_fetch(curinputvarno,
241  parsetree->rtable);
242  }
243  if (get_rte_attribute_is_dropped(curinputrte,
244  aliasvar->varattno))
245  {
246  /* Replace the join alias item with a NULL */
247  aliasitem = NULL;
248  }
249  }
250  newaliasvars = lappend(newaliasvars, aliasitem);
251  }
252  rte->joinaliasvars = newaliasvars;
253  break;
254 
255  case RTE_SUBQUERY:
256 
257  /*
258  * The subquery RTE itself is all right, but we have to
259  * recurse to process the represented subquery.
260  */
262  forExecute,
263  (forUpdatePushedDown ||
264  get_parse_rowmark(parsetree, rt_index) != NULL));
265  break;
266 
267  default:
268  /* ignore other types of RTEs */
269  break;
270  }
271  }
272 
273  /* Recurse into subqueries in WITH */
274  foreach(l, parsetree->cteList)
275  {
276  CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
277 
278  AcquireRewriteLocks((Query *) cte->ctequery, forExecute, false);
279  }
280 
281  /*
282  * Recurse into sublink subqueries, too. But we already did the ones in
283  * the rtable and cteList.
284  */
285  if (parsetree->hasSubLinks)
286  query_tree_walker(parsetree, acquireLocksOnSubLinks, &context,
288 }
#define NIL
Definition: pg_list.h:65
bool query_tree_walker(Query *query, bool(*walker)(), void *context, int flags)
Definition: nodeFuncs.c:2274
#define IsA(nodeptr, _type_)
Definition: nodes.h:576
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:133
List * joinaliasvars
Definition: parsenodes.h:1030
Index varlevelsup
Definition: primnodes.h:177
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:525
AttrNumber varattno
Definition: primnodes.h:172
Form_pg_class rd_rel
Definition: rel.h:83
Definition: primnodes.h:167
#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:322
Index varno
Definition: primnodes.h:170
#define RowShareLock
Definition: lockdefs.h:37
bool get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
unsigned int Index
Definition: c.h:475
#define Assert(condition)
Definition: c.h:732
#define lfirst(lc)
Definition: pg_list.h:190
RTEKind rtekind
Definition: parsenodes.h:974
List * cteList
Definition: parsenodes.h:135
Query * subquery
Definition: parsenodes.h:1009
bool hasSubLinks
Definition: parsenodes.h:128
#define elog(elevel,...)
Definition: elog.h:226
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:612

◆ build_column_default()

Node* build_column_default ( Relation  rel,
int  attrno 
)

Definition at line 1120 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().

1121 {
1122  TupleDesc rd_att = rel->rd_att;
1123  Form_pg_attribute att_tup = TupleDescAttr(rd_att, attrno - 1);
1124  Oid atttype = att_tup->atttypid;
1125  int32 atttypmod = att_tup->atttypmod;
1126  Node *expr = NULL;
1127  Oid exprtype;
1128 
1129  if (att_tup->attidentity)
1130  {
1132 
1133  nve->seqid = getIdentitySequence(RelationGetRelid(rel), attrno, false);
1134  nve->typeId = att_tup->atttypid;
1135 
1136  return (Node *) nve;
1137  }
1138 
1139  /*
1140  * Scan to see if relation has a default for this column.
1141  */
1142  if (att_tup->atthasdef && rd_att->constr &&
1143  rd_att->constr->num_defval > 0)
1144  {
1145  AttrDefault *defval = rd_att->constr->defval;
1146  int ndef = rd_att->constr->num_defval;
1147 
1148  while (--ndef >= 0)
1149  {
1150  if (attrno == defval[ndef].adnum)
1151  {
1152  /*
1153  * Found it, convert string representation to node tree.
1154  */
1155  expr = stringToNode(defval[ndef].adbin);
1156  break;
1157  }
1158  }
1159  }
1160 
1161  /*
1162  * No per-column default, so look for a default for the type itself. But
1163  * not for generated columns.
1164  */
1165  if (expr == NULL && !att_tup->attgenerated)
1166  expr = get_typdefault(atttype);
1167 
1168  if (expr == NULL)
1169  return NULL; /* No default anywhere */
1170 
1171  /*
1172  * Make sure the value is coerced to the target column type; this will
1173  * generally be true already, but there seem to be some corner cases
1174  * involving domain defaults where it might not be true. This should match
1175  * the parser's processing of non-defaulted expressions --- see
1176  * transformAssignedExpr().
1177  */
1178  exprtype = exprType(expr);
1179 
1180  expr = coerce_to_target_type(NULL, /* no UNKNOWN params here */
1181  expr, exprtype,
1182  atttype, atttypmod,
1185  -1);
1186  if (expr == NULL)
1187  ereport(ERROR,
1188  (errcode(ERRCODE_DATATYPE_MISMATCH),
1189  errmsg("column \"%s\" is of type %s"
1190  " but default expression is of type %s",
1191  NameStr(att_tup->attname),
1192  format_type_be(atttype),
1193  format_type_be(exprtype)),
1194  errhint("You will need to rewrite or cast the expression.")));
1195 
1196  return expr;
1197 }
int errhint(const char *fmt,...)
Definition: elog.c:974
#define TupleDescAttr(tupdesc, i)
Definition: tupdesc.h:92
Definition: nodes.h:525
int errcode(int sqlerrcode)
Definition: elog.c:570
void * stringToNode(const char *str)
Definition: read.c:89
char * format_type_be(Oid type_oid)
Definition: format_type.c:326
unsigned int Oid
Definition: postgres_ext.h:31
Oid getIdentitySequence(Oid relid, AttrNumber attnum, bool missing_ok)
Definition: pg_depend.c:780
signed int int32
Definition: c.h:346
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:78
TupleConstr * constr
Definition: tupdesc.h:85
FormData_pg_attribute * Form_pg_attribute
Definition: pg_attribute.h:200
#define ereport(elevel, rest)
Definition: elog.h:141
TupleDesc rd_att
Definition: rel.h:84
#define makeNode(_type_)
Definition: nodes.h:573
Node * get_typdefault(Oid typid)
Definition: lsyscache.c:2226
Oid exprType(const Node *expr)
Definition: nodeFuncs.c:42
uint16 num_defval
Definition: tupdesc.h:42
int errmsg(const char *fmt,...)
Definition: elog.c:784
#define NameStr(name)
Definition: c.h:609
#define RelationGetRelid(relation)
Definition: rel.h:419

◆ get_view_query()

Query* get_view_query ( Relation  view)

Definition at line 2294 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().

2295 {
2296  int i;
2297 
2298  Assert(view->rd_rel->relkind == RELKIND_VIEW);
2299 
2300  for (i = 0; i < view->rd_rules->numLocks; i++)
2301  {
2302  RewriteRule *rule = view->rd_rules->rules[i];
2303 
2304  if (rule->event == CMD_SELECT)
2305  {
2306  /* A _RETURN rule should have only one action */
2307  if (list_length(rule->actions) != 1)
2308  elog(ERROR, "invalid _RETURN rule action specification");
2309 
2310  return (Query *) linitial(rule->actions);
2311  }
2312  }
2313 
2314  elog(ERROR, "failed to find _RETURN rule for view");
2315  return NULL; /* keep compiler quiet */
2316 }
int numLocks
Definition: prs2lock.h:42
Form_pg_class rd_rel
Definition: rel.h:83
Definition: localtime.c:79
#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:732
RuleLock * rd_rules
Definition: rel.h:87
static int list_length(const List *l)
Definition: pg_list.h:169
#define elog(elevel,...)
Definition: elog.h:226
int i

◆ QueryRewrite()

List* QueryRewrite ( Query parsetree)

Definition at line 3852 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().

3853 {
3854  uint64 input_query_id = parsetree->queryId;
3855  List *querylist;
3856  List *results;
3857  ListCell *l;
3858  CmdType origCmdType;
3859  bool foundOriginalQuery;
3860  Query *lastInstead;
3861 
3862  /*
3863  * This function is only applied to top-level original queries
3864  */
3865  Assert(parsetree->querySource == QSRC_ORIGINAL);
3866  Assert(parsetree->canSetTag);
3867 
3868  /*
3869  * Step 1
3870  *
3871  * Apply all non-SELECT rules possibly getting 0 or many queries
3872  */
3873  querylist = RewriteQuery(parsetree, NIL);
3874 
3875  /*
3876  * Step 2
3877  *
3878  * Apply all the RIR rules on each query
3879  *
3880  * This is also a handy place to mark each query with the original queryId
3881  */
3882  results = NIL;
3883  foreach(l, querylist)
3884  {
3885  Query *query = (Query *) lfirst(l);
3886 
3887  query = fireRIRrules(query, NIL);
3888 
3889  query->queryId = input_query_id;
3890 
3891  results = lappend(results, query);
3892  }
3893 
3894  /*
3895  * Step 3
3896  *
3897  * Determine which, if any, of the resulting queries is supposed to set
3898  * the command-result tag; and update the canSetTag fields accordingly.
3899  *
3900  * If the original query is still in the list, it sets the command tag.
3901  * Otherwise, the last INSTEAD query of the same kind as the original is
3902  * allowed to set the tag. (Note these rules can leave us with no query
3903  * setting the tag. The tcop code has to cope with this by setting up a
3904  * default tag based on the original un-rewritten query.)
3905  *
3906  * The Asserts verify that at most one query in the result list is marked
3907  * canSetTag. If we aren't checking asserts, we can fall out of the loop
3908  * as soon as we find the original query.
3909  */
3910  origCmdType = parsetree->commandType;
3911  foundOriginalQuery = false;
3912  lastInstead = NULL;
3913 
3914  foreach(l, results)
3915  {
3916  Query *query = (Query *) lfirst(l);
3917 
3918  if (query->querySource == QSRC_ORIGINAL)
3919  {
3920  Assert(query->canSetTag);
3921  Assert(!foundOriginalQuery);
3922  foundOriginalQuery = true;
3923 #ifndef USE_ASSERT_CHECKING
3924  break;
3925 #endif
3926  }
3927  else
3928  {
3929  Assert(!query->canSetTag);
3930  if (query->commandType == origCmdType &&
3931  (query->querySource == QSRC_INSTEAD_RULE ||
3933  lastInstead = query;
3934  }
3935  }
3936 
3937  if (!foundOriginalQuery && lastInstead != NULL)
3938  lastInstead->canSetTag = true;
3939 
3940  return results;
3941 }
#define NIL
Definition: pg_list.h:65
static List * RewriteQuery(Query *parsetree, List *rewrite_events)
List * lappend(List *list, void *datum)
Definition: list.c:322
uint64 queryId
Definition: parsenodes.h:116
CmdType commandType
Definition: parsenodes.h:112
QuerySource querySource
Definition: parsenodes.h:114
#define Assert(condition)
Definition: c.h:732
#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:668

◆ relation_is_updatable()

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

Definition at line 2639 of file rewriteHandler.c.

References AccessShareLock, adjust_view_column_set(), ALL_EVENTS, Assert, bms_int_members(), bms_is_empty(), 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, linitial, RuleLock::numLocks, RewriteRule::qual, RelationData::rd_rel, RelationData::rd_rules, relation_close(), relation_is_updatable(), 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().

2642 {
2643  int events = 0;
2644  Relation rel;
2645  RuleLock *rulelocks;
2646 
2647 #define ALL_EVENTS ((1 << CMD_INSERT) | (1 << CMD_UPDATE) | (1 << CMD_DELETE))
2648 
2649  rel = try_relation_open(reloid, AccessShareLock);
2650 
2651  /*
2652  * If the relation doesn't exist, return zero rather than throwing an
2653  * error. This is helpful since scanning an information_schema view under
2654  * MVCC rules can result in referencing rels that have actually been
2655  * deleted already.
2656  */
2657  if (rel == NULL)
2658  return 0;
2659 
2660  /* If the relation is a table, it is always updatable */
2661  if (rel->rd_rel->relkind == RELKIND_RELATION ||
2662  rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
2663  {
2665  return ALL_EVENTS;
2666  }
2667 
2668  /* Look for unconditional DO INSTEAD rules, and note supported events */
2669  rulelocks = rel->rd_rules;
2670  if (rulelocks != NULL)
2671  {
2672  int i;
2673 
2674  for (i = 0; i < rulelocks->numLocks; i++)
2675  {
2676  if (rulelocks->rules[i]->isInstead &&
2677  rulelocks->rules[i]->qual == NULL)
2678  {
2679  events |= ((1 << rulelocks->rules[i]->event) & ALL_EVENTS);
2680  }
2681  }
2682 
2683  /* If we have rules for all events, we're done */
2684  if (events == ALL_EVENTS)
2685  {
2687  return events;
2688  }
2689  }
2690 
2691  /* Similarly look for INSTEAD OF triggers, if they are to be included */
2692  if (include_triggers)
2693  {
2694  TriggerDesc *trigDesc = rel->trigdesc;
2695 
2696  if (trigDesc)
2697  {
2698  if (trigDesc->trig_insert_instead_row)
2699  events |= (1 << CMD_INSERT);
2700  if (trigDesc->trig_update_instead_row)
2701  events |= (1 << CMD_UPDATE);
2702  if (trigDesc->trig_delete_instead_row)
2703  events |= (1 << CMD_DELETE);
2704 
2705  /* If we have triggers for all events, we're done */
2706  if (events == ALL_EVENTS)
2707  {
2709  return events;
2710  }
2711  }
2712  }
2713 
2714  /* If this is a foreign table, check which update events it supports */
2715  if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
2716  {
2717  FdwRoutine *fdwroutine = GetFdwRoutineForRelation(rel, false);
2718 
2719  if (fdwroutine->IsForeignRelUpdatable != NULL)
2720  events |= fdwroutine->IsForeignRelUpdatable(rel);
2721  else
2722  {
2723  /* Assume presence of executor functions is sufficient */
2724  if (fdwroutine->ExecForeignInsert != NULL)
2725  events |= (1 << CMD_INSERT);
2726  if (fdwroutine->ExecForeignUpdate != NULL)
2727  events |= (1 << CMD_UPDATE);
2728  if (fdwroutine->ExecForeignDelete != NULL)
2729  events |= (1 << CMD_DELETE);
2730  }
2731 
2733  return events;
2734  }
2735 
2736  /* Check if this is an automatically updatable view */
2737  if (rel->rd_rel->relkind == RELKIND_VIEW)
2738  {
2739  Query *viewquery = get_view_query(rel);
2740 
2741  if (view_query_is_auto_updatable(viewquery, false) == NULL)
2742  {
2743  Bitmapset *updatable_cols;
2744  int auto_events;
2745  RangeTblRef *rtr;
2746  RangeTblEntry *base_rte;
2747  Oid baseoid;
2748 
2749  /*
2750  * Determine which of the view's columns are updatable. If there
2751  * are none within the set of columns we are looking at, then the
2752  * view doesn't support INSERT/UPDATE, but it may still support
2753  * DELETE.
2754  */
2755  view_cols_are_auto_updatable(viewquery, NULL,
2756  &updatable_cols, NULL);
2757 
2758  if (include_cols != NULL)
2759  updatable_cols = bms_int_members(updatable_cols, include_cols);
2760 
2761  if (bms_is_empty(updatable_cols))
2762  auto_events = (1 << CMD_DELETE); /* May support DELETE */
2763  else
2764  auto_events = ALL_EVENTS; /* May support all events */
2765 
2766  /*
2767  * The base relation must also support these update commands.
2768  * Tables are always updatable, but for any other kind of base
2769  * relation we must do a recursive check limited to the columns
2770  * referenced by the locally updatable columns in this view.
2771  */
2772  rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
2773  base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
2774  Assert(base_rte->rtekind == RTE_RELATION);
2775 
2776  if (base_rte->relkind != RELKIND_RELATION &&
2777  base_rte->relkind != RELKIND_PARTITIONED_TABLE)
2778  {
2779  baseoid = base_rte->relid;
2780  include_cols = adjust_view_column_set(updatable_cols,
2781  viewquery->targetList);
2782  auto_events &= relation_is_updatable(baseoid,
2783  include_triggers,
2784  include_cols);
2785  }
2786  events |= auto_events;
2787  }
2788  }
2789 
2790  /* If we reach here, the relation may support some update commands */
2792  return events;
2793 }
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:1496
Form_pg_class rd_rel
Definition: rel.h:83
unsigned int Oid
Definition: postgres_ext.h:31
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:57
#define linitial(l)
Definition: pg_list.h:195
List * rtable
Definition: parsenodes.h:137
#define ALL_EVENTS
TriggerDesc * trigdesc
Definition: rel.h:89
int relation_is_updatable(Oid reloid, bool include_triggers, Bitmapset *include_cols)
CmdType event
Definition: prs2lock.h:27
RewriteRule ** rules
Definition: prs2lock.h:43
#define rt_fetch(rangetable_index, rangetable)
Definition: parsetree.h:31
bool trig_update_instead_row
Definition: reltrigger.h:62
bool bms_is_empty(const Bitmapset *a)
Definition: bitmapset.c:701
bool trig_delete_instead_row
Definition: reltrigger.h:67
static Bitmapset * adjust_view_column_set(Bitmapset *cols, List *targetlist)
ExecForeignUpdate_function ExecForeignUpdate
Definition: fdwapi.h:212
void relation_close(Relation relation, LOCKMODE lockmode)
Definition: relation.c:206
#define Assert(condition)
Definition: c.h:732
RuleLock * rd_rules
Definition: rel.h:87
RTEKind rtekind
Definition: parsenodes.h:974
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)

◆ rewriteTargetListUD()

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

Definition at line 1443 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().

1445 {
1446  Var *var = NULL;
1447  const char *attrname;
1448  TargetEntry *tle;
1449 
1450  if (target_relation->rd_rel->relkind == RELKIND_RELATION ||
1451  target_relation->rd_rel->relkind == RELKIND_MATVIEW ||
1452  target_relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
1453  {
1454  /*
1455  * Emit CTID so that executor can find the row to update or delete.
1456  */
1457  var = makeVar(parsetree->resultRelation,
1459  TIDOID,
1460  -1,
1461  InvalidOid,
1462  0);
1463 
1464  attrname = "ctid";
1465  }
1466  else if (target_relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
1467  {
1468  /*
1469  * Let the foreign table's FDW add whatever junk TLEs it wants.
1470  */
1471  FdwRoutine *fdwroutine;
1472 
1473  fdwroutine = GetFdwRoutineForRelation(target_relation, false);
1474 
1475  if (fdwroutine->AddForeignUpdateTargets != NULL)
1476  fdwroutine->AddForeignUpdateTargets(parsetree, target_rte,
1477  target_relation);
1478 
1479  /*
1480  * If we have a row-level trigger corresponding to the operation, emit
1481  * a whole-row Var so that executor will have the "old" row to pass to
1482  * the trigger. Alas, this misses system columns.
1483  */
1484  if (target_relation->trigdesc &&
1485  ((parsetree->commandType == CMD_UPDATE &&
1486  (target_relation->trigdesc->trig_update_after_row ||
1487  target_relation->trigdesc->trig_update_before_row)) ||
1488  (parsetree->commandType == CMD_DELETE &&
1489  (target_relation->trigdesc->trig_delete_after_row ||
1490  target_relation->trigdesc->trig_delete_before_row))))
1491  {
1492  var = makeWholeRowVar(target_rte,
1493  parsetree->resultRelation,
1494  0,
1495  false);
1496 
1497  attrname = "wholerow";
1498  }
1499  }
1500 
1501  if (var != NULL)
1502  {
1503  tle = makeTargetEntry((Expr *) var,
1504  list_length(parsetree->targetList) + 1,
1505  pstrdup(attrname),
1506  true);
1507 
1508  parsetree->targetList = lappend(parsetree->targetList, tle);
1509  }
1510 }
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:83
Definition: primnodes.h:167
AddForeignUpdateTargets_function AddForeignUpdateTargets
Definition: fdwapi.h:208
List * targetList
Definition: parsenodes.h:140
TriggerDesc * trigdesc
Definition: rel.h:89
bool trig_delete_after_row
Definition: reltrigger.h:66
bool trig_update_before_row
Definition: reltrigger.h:60
TargetEntry * makeTargetEntry(Expr *expr, AttrNumber resno, char *resname, bool resjunk)
Definition: makefuncs.c:236
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:61
List * lappend(List *list, void *datum)
Definition: list.c:322
#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:65

◆ view_query_is_auto_updatable()

const char* view_query_is_auto_updatable ( Query viewquery,
bool  check_cols 
)

Definition at line 2413 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().

2414 {
2415  RangeTblRef *rtr;
2416  RangeTblEntry *base_rte;
2417 
2418  /*----------
2419  * Check if the view is simply updatable. According to SQL-92 this means:
2420  * - No DISTINCT clause.
2421  * - Each TLE is a column reference, and each column appears at most once.
2422  * - FROM contains exactly one base relation.
2423  * - No GROUP BY or HAVING clauses.
2424  * - No set operations (UNION, INTERSECT or EXCEPT).
2425  * - No sub-queries in the WHERE clause that reference the target table.
2426  *
2427  * We ignore that last restriction since it would be complex to enforce
2428  * and there isn't any actual benefit to disallowing sub-queries. (The
2429  * semantic issues that the standard is presumably concerned about don't
2430  * arise in Postgres, since any such sub-query will not see any updates
2431  * executed by the outer query anyway, thanks to MVCC snapshotting.)
2432  *
2433  * We also relax the second restriction by supporting part of SQL:1999
2434  * feature T111, which allows for a mix of updatable and non-updatable
2435  * columns, provided that an INSERT or UPDATE doesn't attempt to assign to
2436  * a non-updatable column.
2437  *
2438  * In addition we impose these constraints, involving features that are
2439  * not part of SQL-92:
2440  * - No CTEs (WITH clauses).
2441  * - No OFFSET or LIMIT clauses (this matches a SQL:2008 restriction).
2442  * - No system columns (including whole-row references) in the tlist.
2443  * - No window functions in the tlist.
2444  * - No set-returning functions in the tlist.
2445  *
2446  * Note that we do these checks without recursively expanding the view.
2447  * If the base relation is a view, we'll recursively deal with it later.
2448  *----------
2449  */
2450  if (viewquery->distinctClause != NIL)
2451  return gettext_noop("Views containing DISTINCT are not automatically updatable.");
2452 
2453  if (viewquery->groupClause != NIL || viewquery->groupingSets)
2454  return gettext_noop("Views containing GROUP BY are not automatically updatable.");
2455 
2456  if (viewquery->havingQual != NULL)
2457  return gettext_noop("Views containing HAVING are not automatically updatable.");
2458 
2459  if (viewquery->setOperations != NULL)
2460  return gettext_noop("Views containing UNION, INTERSECT, or EXCEPT are not automatically updatable.");
2461 
2462  if (viewquery->cteList != NIL)
2463  return gettext_noop("Views containing WITH are not automatically updatable.");
2464 
2465  if (viewquery->limitOffset != NULL || viewquery->limitCount != NULL)
2466  return gettext_noop("Views containing LIMIT or OFFSET are not automatically updatable.");
2467 
2468  /*
2469  * We must not allow window functions or set returning functions in the
2470  * targetlist. Otherwise we might end up inserting them into the quals of
2471  * the main query. We must also check for aggregates in the targetlist in
2472  * case they appear without a GROUP BY.
2473  *
2474  * These restrictions ensure that each row of the view corresponds to a
2475  * unique row in the underlying base relation.
2476  */
2477  if (viewquery->hasAggs)
2478  return gettext_noop("Views that return aggregate functions are not automatically updatable.");
2479 
2480  if (viewquery->hasWindowFuncs)
2481  return gettext_noop("Views that return window functions are not automatically updatable.");
2482 
2483  if (viewquery->hasTargetSRFs)
2484  return gettext_noop("Views that return set-returning functions are not automatically updatable.");
2485 
2486  /*
2487  * The view query should select from a single base relation, which must be
2488  * a table or another view.
2489  */
2490  if (list_length(viewquery->jointree->fromlist) != 1)
2491  return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2492 
2493  rtr = (RangeTblRef *) linitial(viewquery->jointree->fromlist);
2494  if (!IsA(rtr, RangeTblRef))
2495  return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2496 
2497  base_rte = rt_fetch(rtr->rtindex, viewquery->rtable);
2498  if (base_rte->rtekind != RTE_RELATION ||
2499  (base_rte->relkind != RELKIND_RELATION &&
2500  base_rte->relkind != RELKIND_FOREIGN_TABLE &&
2501  base_rte->relkind != RELKIND_VIEW &&
2502  base_rte->relkind != RELKIND_PARTITIONED_TABLE))
2503  return gettext_noop("Views that do not select from a single table or view are not automatically updatable.");
2504 
2505  if (base_rte->tablesample)
2506  return gettext_noop("Views containing TABLESAMPLE are not automatically updatable.");
2507 
2508  /*
2509  * Check that the view has at least one updatable column. This is required
2510  * for INSERT/UPDATE but not for DELETE.
2511  */
2512  if (check_cols)
2513  {
2514  ListCell *cell;
2515  bool found;
2516 
2517  found = false;
2518  foreach(cell, viewquery->targetList)
2519  {
2520  TargetEntry *tle = (TargetEntry *) lfirst(cell);
2521 
2522  if (view_col_is_auto_updatable(rtr, tle) == NULL)
2523  {
2524  found = true;
2525  break;
2526  }
2527  }
2528 
2529  if (!found)
2530  return gettext_noop("Views that have no updatable columns are not automatically updatable.");
2531  }
2532 
2533  return NULL; /* the view is updatable */
2534 }
Node * limitOffset
Definition: parsenodes.h:160
#define NIL
Definition: pg_list.h:65
#define IsA(nodeptr, _type_)
Definition: nodes.h:576
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:1117
List * fromlist
Definition: primnodes.h:1496
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:974
List * cteList
Definition: parsenodes.h:135
Node * setOperations
Definition: parsenodes.h:165
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:1004