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Functions
comment.h File Reference
#include "catalog/objectaddress.h"
#include "nodes/parsenodes.h"
Include dependency graph for comment.h:
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Functions

ObjectAddress CommentObject (CommentStmt *stmt)
 
void DeleteComments (Oid oid, Oid classoid, int32 subid)
 
void CreateComments (Oid oid, Oid classoid, int32 subid, const char *comment)
 
void DeleteSharedComments (Oid oid, Oid classoid)
 
void CreateSharedComments (Oid oid, Oid classoid, const char *comment)
 
char * GetComment (Oid oid, Oid classoid, int32 subid)
 

Function Documentation

◆ CommentObject()

ObjectAddress CommentObject ( CommentStmt *  stmt)

Definition at line 40 of file comment.c.

References check_object_ownership(), ObjectAddress::classId, CommentStmt::comment, CreateComments(), CreateSharedComments(), ereport, errcode(), errmsg(), ERROR, get_database_oid(), get_object_address(), GetUserId(), InvalidObjectAddress, NoLock, CommentStmt::object, OBJECT_COLUMN, OBJECT_DATABASE, OBJECT_ROLE, OBJECT_TABLESPACE, ObjectAddress::objectId, ObjectAddress::objectSubId, CommentStmt::objtype, OidIsValid, RelationData::rd_rel, relation_close(), RelationGetRelationName, ShareUpdateExclusiveLock, strVal, and WARNING.

Referenced by ATExecCmd(), ProcessUtilitySlow(), and standard_ProcessUtility().

41 {
42  Relation relation;
43  ObjectAddress address = InvalidObjectAddress;
44 
45  /*
46  * When loading a dump, we may see a COMMENT ON DATABASE for the old name
47  * of the database. Erroring out would prevent pg_restore from completing
48  * (which is really pg_restore's fault, but for now we will work around
49  * the problem here). Consensus is that the best fix is to treat wrong
50  * database name as a WARNING not an ERROR; hence, the following special
51  * case.
52  */
53  if (stmt->objtype == OBJECT_DATABASE)
54  {
55  char *database = strVal((Value *) stmt->object);
56 
57  if (!OidIsValid(get_database_oid(database, true)))
58  {
59  ereport(WARNING,
60  (errcode(ERRCODE_UNDEFINED_DATABASE),
61  errmsg("database \"%s\" does not exist", database)));
62  return address;
63  }
64  }
65 
66  /*
67  * Translate the parser representation that identifies this object into an
68  * ObjectAddress. get_object_address() will throw an error if the object
69  * does not exist, and will also acquire a lock on the target to guard
70  * against concurrent DROP operations.
71  */
72  address = get_object_address(stmt->objtype, stmt->object,
73  &relation, ShareUpdateExclusiveLock, false);
74 
75  /* Require ownership of the target object. */
76  check_object_ownership(GetUserId(), stmt->objtype, address,
77  stmt->object, relation);
78 
79  /* Perform other integrity checks as needed. */
80  switch (stmt->objtype)
81  {
82  case OBJECT_COLUMN:
83 
84  /*
85  * Allow comments only on columns of tables, views, materialized
86  * views, composite types, and foreign tables (which are the only
87  * relkinds for which pg_dump will dump per-column comments). In
88  * particular we wish to disallow comments on index columns,
89  * because the naming of an index's columns may change across PG
90  * versions, so dumping per-column comments could create reload
91  * failures.
92  */
93  if (relation->rd_rel->relkind != RELKIND_RELATION &&
94  relation->rd_rel->relkind != RELKIND_VIEW &&
95  relation->rd_rel->relkind != RELKIND_MATVIEW &&
96  relation->rd_rel->relkind != RELKIND_COMPOSITE_TYPE &&
97  relation->rd_rel->relkind != RELKIND_FOREIGN_TABLE &&
98  relation->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
99  ereport(ERROR,
100  (errcode(ERRCODE_WRONG_OBJECT_TYPE),
101  errmsg("\"%s\" is not a table, view, materialized view, composite type, or foreign table",
102  RelationGetRelationName(relation))));
103  break;
104  default:
105  break;
106  }
107 
108  /*
109  * Databases, tablespaces, and roles are cluster-wide objects, so any
110  * comments on those objects are recorded in the shared pg_shdescription
111  * catalog. Comments on all other objects are recorded in pg_description.
112  */
113  if (stmt->objtype == OBJECT_DATABASE || stmt->objtype == OBJECT_TABLESPACE
114  || stmt->objtype == OBJECT_ROLE)
115  CreateSharedComments(address.objectId, address.classId, stmt->comment);
116  else
117  CreateComments(address.objectId, address.classId, address.objectSubId,
118  stmt->comment);
119 
120  /*
121  * If get_object_address() opened the relation for us, we close it to keep
122  * the reference count correct - but we retain any locks acquired by
123  * get_object_address() until commit time, to guard against concurrent
124  * activity.
125  */
126  if (relation != NULL)
127  relation_close(relation, NoLock);
128 
129  return address;
130 }
CommentStmt::objtype
ObjectType objtype
Definition: parsenodes.h:2768
CreateComments
void CreateComments(Oid oid, Oid classoid, int32 subid, const char *comment)
Definition: comment.c:142
GetUserId
Oid GetUserId(void)
Definition: miscinit.c:478
strVal
#define strVal(v)
Definition: value.h:54
errcode
int errcode(int sqlerrcode)
Definition: elog.c:698
CommentStmt::comment
char * comment
Definition: parsenodes.h:2770
CommentStmt::object
Node * object
Definition: parsenodes.h:2769
RelationData::rd_rel
Form_pg_class rd_rel
Definition: rel.h:109
OidIsValid
#define OidIsValid(objectId)
Definition: c.h:710
ERROR
#define ERROR
Definition: elog.h:46
NoLock
#define NoLock
Definition: lockdefs.h:34
RelationGetRelationName
#define RelationGetRelationName(relation)
Definition: rel.h:503
WARNING
#define WARNING
Definition: elog.h:40
get_database_oid
Oid get_database_oid(const char *dbname, bool missing_ok)
Definition: dbcommands.c:2108
ereport
#define ereport(elevel,...)
Definition: elog.h:157
ShareUpdateExclusiveLock
#define ShareUpdateExclusiveLock
Definition: lockdefs.h:39
relation_close
void relation_close(Relation relation, LOCKMODE lockmode)
Definition: relation.c:206
Value
Definition: value.h:42
CreateSharedComments
void CreateSharedComments(Oid oid, Oid classoid, const char *comment)
Definition: comment.c:237
get_object_address
ObjectAddress get_object_address(ObjectType objtype, Node *object, Relation *relp, LOCKMODE lockmode, bool missing_ok)
Definition: objectaddress.c:929
check_object_ownership
void check_object_ownership(Oid roleid, ObjectType objtype, ObjectAddress address, Node *object, Relation relation)
Definition: objectaddress.c:2366
InvalidObjectAddress
const ObjectAddress InvalidObjectAddress
Definition: objectaddress.c:846
errmsg
int errmsg(const char *fmt,...)
Definition: elog.c:909

◆ CreateComments()

void CreateComments ( Oid  oid,
Oid  classoid,
int32  subid,
const char *  comment 
)

Definition at line 142 of file comment.c.

References BTEqualStrategyNumber, CatalogTupleDelete(), CatalogTupleInsert(), CatalogTupleUpdate(), CStringGetTextDatum, DescriptionObjIndexId, heap_form_tuple(), heap_freetuple(), heap_modify_tuple(), i, Int32GetDatum, NoLock, ObjectIdGetDatum, RelationGetDescr, RowExclusiveLock, ScanKeyInit(), systable_beginscan(), systable_endscan(), systable_getnext(), HeapTupleData::t_self, table_close(), table_open(), and values.

Referenced by CommentObject(), CreateExtensionInternal(), CreateStatistics(), DefineIndex(), and pg_import_system_collations().

143 {
144  Relation description;
145  ScanKeyData skey[3];
146  SysScanDesc sd;
147  HeapTuple oldtuple;
148  HeapTuple newtuple = NULL;
149  Datum values[Natts_pg_description];
150  bool nulls[Natts_pg_description];
151  bool replaces[Natts_pg_description];
152  int i;
153 
154  /* Reduce empty-string to NULL case */
155  if (comment != NULL && strlen(comment) == 0)
156  comment = NULL;
157 
158  /* Prepare to form or update a tuple, if necessary */
159  if (comment != NULL)
160  {
161  for (i = 0; i < Natts_pg_description; i++)
162  {
163  nulls[i] = false;
164  replaces[i] = true;
165  }
166  values[Anum_pg_description_objoid - 1] = ObjectIdGetDatum(oid);
167  values[Anum_pg_description_classoid - 1] = ObjectIdGetDatum(classoid);
168  values[Anum_pg_description_objsubid - 1] = Int32GetDatum(subid);
169  values[Anum_pg_description_description - 1] = CStringGetTextDatum(comment);
170  }
171 
172  /* Use the index to search for a matching old tuple */
173 
174  ScanKeyInit(&skey[0],
175  Anum_pg_description_objoid,
176  BTEqualStrategyNumber, F_OIDEQ,
177  ObjectIdGetDatum(oid));
178  ScanKeyInit(&skey[1],
179  Anum_pg_description_classoid,
180  BTEqualStrategyNumber, F_OIDEQ,
181  ObjectIdGetDatum(classoid));
182  ScanKeyInit(&skey[2],
183  Anum_pg_description_objsubid,
184  BTEqualStrategyNumber, F_INT4EQ,
185  Int32GetDatum(subid));
186 
187  description = table_open(DescriptionRelationId, RowExclusiveLock);
188 
189  sd = systable_beginscan(description, DescriptionObjIndexId, true,
190  NULL, 3, skey);
191 
192  while ((oldtuple = systable_getnext(sd)) != NULL)
193  {
194  /* Found the old tuple, so delete or update it */
195 
196  if (comment == NULL)
197  CatalogTupleDelete(description, &oldtuple->t_self);
198  else
199  {
200  newtuple = heap_modify_tuple(oldtuple, RelationGetDescr(description), values,
201  nulls, replaces);
202  CatalogTupleUpdate(description, &oldtuple->t_self, newtuple);
203  }
204 
205  break; /* Assume there can be only one match */
206  }
207 
208  systable_endscan(sd);
209 
210  /* If we didn't find an old tuple, insert a new one */
211 
212  if (newtuple == NULL && comment != NULL)
213  {
214  newtuple = heap_form_tuple(RelationGetDescr(description),
215  values, nulls);
216  CatalogTupleInsert(description, newtuple);
217  }
218 
219  if (newtuple != NULL)
220  heap_freetuple(newtuple);
221 
222  /* Done */
223 
224  table_close(description, NoLock);
225 }
table_close
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:167
DescriptionObjIndexId
#define DescriptionObjIndexId
Definition: pg_description.h:69
systable_endscan
void systable_endscan(SysScanDesc sysscan)
Definition: genam.c:595
RelationGetDescr
#define RelationGetDescr(relation)
Definition: rel.h:495
CatalogTupleDelete
void CatalogTupleDelete(Relation heapRel, ItemPointer tid)
Definition: indexing.c:350
heap_form_tuple
HeapTuple heap_form_tuple(TupleDesc tupleDescriptor, Datum *values, bool *isnull)
Definition: heaptuple.c:1020
heap_freetuple
void heap_freetuple(HeapTuple htup)
Definition: heaptuple.c:1338
systable_beginscan
SysScanDesc systable_beginscan(Relation heapRelation, Oid indexId, bool indexOK, Snapshot snapshot, int nkeys, ScanKey key)
Definition: genam.c:383
systable_getnext
HeapTuple systable_getnext(SysScanDesc sysscan)
Definition: genam.c:502
ObjectIdGetDatum
#define ObjectIdGetDatum(X)
Definition: postgres.h:551
HeapTupleData::t_self
ItemPointerData t_self
Definition: htup.h:65
NoLock
#define NoLock
Definition: lockdefs.h:34
RowExclusiveLock
#define RowExclusiveLock
Definition: lockdefs.h:38
Datum
uintptr_t Datum
Definition: postgres.h:411
CatalogTupleUpdate
void CatalogTupleUpdate(Relation heapRel, ItemPointer otid, HeapTuple tup)
Definition: indexing.c:301
values
static Datum values[MAXATTR]
Definition: bootstrap.c:166
Int32GetDatum
#define Int32GetDatum(X)
Definition: postgres.h:523
i
int i
Definition: preproc-comment.c:23
ScanKeyInit
void ScanKeyInit(ScanKey entry, AttrNumber attributeNumber, StrategyNumber strategy, RegProcedure procedure, Datum argument)
Definition: scankey.c:76
CStringGetTextDatum
#define CStringGetTextDatum(s)
Definition: builtins.h:82
table_open
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
heap_modify_tuple
HeapTuple heap_modify_tuple(HeapTuple tuple, TupleDesc tupleDesc, Datum *replValues, bool *replIsnull, bool *doReplace)
Definition: heaptuple.c:1113
CatalogTupleInsert
void CatalogTupleInsert(Relation heapRel, HeapTuple tup)
Definition: indexing.c:221
BTEqualStrategyNumber
#define BTEqualStrategyNumber
Definition: stratnum.h:31

◆ CreateSharedComments()

void CreateSharedComments ( Oid  oid,
Oid  classoid,
const char *  comment 
)

Definition at line 237 of file comment.c.

References BTEqualStrategyNumber, CatalogTupleDelete(), CatalogTupleInsert(), CatalogTupleUpdate(), CStringGetTextDatum, heap_form_tuple(), heap_freetuple(), heap_modify_tuple(), i, NoLock, ObjectIdGetDatum, RelationGetDescr, RowExclusiveLock, ScanKeyInit(), SharedDescriptionObjIndexId, systable_beginscan(), systable_endscan(), systable_getnext(), HeapTupleData::t_self, table_close(), table_open(), and values.

Referenced by CommentObject().

238 {
239  Relation shdescription;
240  ScanKeyData skey[2];
241  SysScanDesc sd;
242  HeapTuple oldtuple;
243  HeapTuple newtuple = NULL;
244  Datum values[Natts_pg_shdescription];
245  bool nulls[Natts_pg_shdescription];
246  bool replaces[Natts_pg_shdescription];
247  int i;
248 
249  /* Reduce empty-string to NULL case */
250  if (comment != NULL && strlen(comment) == 0)
251  comment = NULL;
252 
253  /* Prepare to form or update a tuple, if necessary */
254  if (comment != NULL)
255  {
256  for (i = 0; i < Natts_pg_shdescription; i++)
257  {
258  nulls[i] = false;
259  replaces[i] = true;
260  }
261  values[Anum_pg_shdescription_objoid - 1] = ObjectIdGetDatum(oid);
262  values[Anum_pg_shdescription_classoid - 1] = ObjectIdGetDatum(classoid);
263  values[Anum_pg_shdescription_description - 1] = CStringGetTextDatum(comment);
264  }
265 
266  /* Use the index to search for a matching old tuple */
267 
268  ScanKeyInit(&skey[0],
269  Anum_pg_shdescription_objoid,
270  BTEqualStrategyNumber, F_OIDEQ,
271  ObjectIdGetDatum(oid));
272  ScanKeyInit(&skey[1],
273  Anum_pg_shdescription_classoid,
274  BTEqualStrategyNumber, F_OIDEQ,
275  ObjectIdGetDatum(classoid));
276 
277  shdescription = table_open(SharedDescriptionRelationId, RowExclusiveLock);
278 
279  sd = systable_beginscan(shdescription, SharedDescriptionObjIndexId, true,
280  NULL, 2, skey);
281 
282  while ((oldtuple = systable_getnext(sd)) != NULL)
283  {
284  /* Found the old tuple, so delete or update it */
285 
286  if (comment == NULL)
287  CatalogTupleDelete(shdescription, &oldtuple->t_self);
288  else
289  {
290  newtuple = heap_modify_tuple(oldtuple, RelationGetDescr(shdescription),
291  values, nulls, replaces);
292  CatalogTupleUpdate(shdescription, &oldtuple->t_self, newtuple);
293  }
294 
295  break; /* Assume there can be only one match */
296  }
297 
298  systable_endscan(sd);
299 
300  /* If we didn't find an old tuple, insert a new one */
301 
302  if (newtuple == NULL && comment != NULL)
303  {
304  newtuple = heap_form_tuple(RelationGetDescr(shdescription),
305  values, nulls);
306  CatalogTupleInsert(shdescription, newtuple);
307  }
308 
309  if (newtuple != NULL)
310  heap_freetuple(newtuple);
311 
312  /* Done */
313 
314  table_close(shdescription, NoLock);
315 }
table_close
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:167
systable_endscan
void systable_endscan(SysScanDesc sysscan)
Definition: genam.c:595
RelationGetDescr
#define RelationGetDescr(relation)
Definition: rel.h:495
SharedDescriptionObjIndexId
#define SharedDescriptionObjIndexId
Definition: pg_shdescription.h:63
CatalogTupleDelete
void CatalogTupleDelete(Relation heapRel, ItemPointer tid)
Definition: indexing.c:350
heap_form_tuple
HeapTuple heap_form_tuple(TupleDesc tupleDescriptor, Datum *values, bool *isnull)
Definition: heaptuple.c:1020
heap_freetuple
void heap_freetuple(HeapTuple htup)
Definition: heaptuple.c:1338
systable_beginscan
SysScanDesc systable_beginscan(Relation heapRelation, Oid indexId, bool indexOK, Snapshot snapshot, int nkeys, ScanKey key)
Definition: genam.c:383
systable_getnext
HeapTuple systable_getnext(SysScanDesc sysscan)
Definition: genam.c:502
ObjectIdGetDatum
#define ObjectIdGetDatum(X)
Definition: postgres.h:551
HeapTupleData::t_self
ItemPointerData t_self
Definition: htup.h:65
NoLock
#define NoLock
Definition: lockdefs.h:34
RowExclusiveLock
#define RowExclusiveLock
Definition: lockdefs.h:38
Datum
uintptr_t Datum
Definition: postgres.h:411
CatalogTupleUpdate
void CatalogTupleUpdate(Relation heapRel, ItemPointer otid, HeapTuple tup)
Definition: indexing.c:301
values
static Datum values[MAXATTR]
Definition: bootstrap.c:166
i
int i
Definition: preproc-comment.c:23
ScanKeyInit
void ScanKeyInit(ScanKey entry, AttrNumber attributeNumber, StrategyNumber strategy, RegProcedure procedure, Datum argument)
Definition: scankey.c:76
CStringGetTextDatum
#define CStringGetTextDatum(s)
Definition: builtins.h:82
table_open
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
heap_modify_tuple
HeapTuple heap_modify_tuple(HeapTuple tuple, TupleDesc tupleDesc, Datum *replValues, bool *replIsnull, bool *doReplace)
Definition: heaptuple.c:1113
CatalogTupleInsert
void CatalogTupleInsert(Relation heapRel, HeapTuple tup)
Definition: indexing.c:221
BTEqualStrategyNumber
#define BTEqualStrategyNumber
Definition: stratnum.h:31

◆ DeleteComments()

void DeleteComments ( Oid  oid,
Oid  classoid,
int32  subid 
)

Definition at line 325 of file comment.c.

References BTEqualStrategyNumber, CatalogTupleDelete(), DescriptionObjIndexId, Int32GetDatum, ObjectIdGetDatum, RowExclusiveLock, ScanKeyInit(), systable_beginscan(), systable_endscan(), systable_getnext(), HeapTupleData::t_self, table_close(), and table_open().

Referenced by deleteOneObject().

326 {
327  Relation description;
328  ScanKeyData skey[3];
329  int nkeys;
330  SysScanDesc sd;
331  HeapTuple oldtuple;
332 
333  /* Use the index to search for all matching old tuples */
334 
335  ScanKeyInit(&skey[0],
336  Anum_pg_description_objoid,
337  BTEqualStrategyNumber, F_OIDEQ,
338  ObjectIdGetDatum(oid));
339  ScanKeyInit(&skey[1],
340  Anum_pg_description_classoid,
341  BTEqualStrategyNumber, F_OIDEQ,
342  ObjectIdGetDatum(classoid));
343 
344  if (subid != 0)
345  {
346  ScanKeyInit(&skey[2],
347  Anum_pg_description_objsubid,
348  BTEqualStrategyNumber, F_INT4EQ,
349  Int32GetDatum(subid));
350  nkeys = 3;
351  }
352  else
353  nkeys = 2;
354 
355  description = table_open(DescriptionRelationId, RowExclusiveLock);
356 
357  sd = systable_beginscan(description, DescriptionObjIndexId, true,
358  NULL, nkeys, skey);
359 
360  while ((oldtuple = systable_getnext(sd)) != NULL)
361  CatalogTupleDelete(description, &oldtuple->t_self);
362 
363  /* Done */
364 
365  systable_endscan(sd);
366  table_close(description, RowExclusiveLock);
367 }
table_close
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:167
DescriptionObjIndexId
#define DescriptionObjIndexId
Definition: pg_description.h:69
systable_endscan
void systable_endscan(SysScanDesc sysscan)
Definition: genam.c:595
CatalogTupleDelete
void CatalogTupleDelete(Relation heapRel, ItemPointer tid)
Definition: indexing.c:350
systable_beginscan
SysScanDesc systable_beginscan(Relation heapRelation, Oid indexId, bool indexOK, Snapshot snapshot, int nkeys, ScanKey key)
Definition: genam.c:383
systable_getnext
HeapTuple systable_getnext(SysScanDesc sysscan)
Definition: genam.c:502
ObjectIdGetDatum
#define ObjectIdGetDatum(X)
Definition: postgres.h:551
HeapTupleData::t_self
ItemPointerData t_self
Definition: htup.h:65
RowExclusiveLock
#define RowExclusiveLock
Definition: lockdefs.h:38
Int32GetDatum
#define Int32GetDatum(X)
Definition: postgres.h:523
ScanKeyInit
void ScanKeyInit(ScanKey entry, AttrNumber attributeNumber, StrategyNumber strategy, RegProcedure procedure, Datum argument)
Definition: scankey.c:76
table_open
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
BTEqualStrategyNumber
#define BTEqualStrategyNumber
Definition: stratnum.h:31

◆ DeleteSharedComments()

void DeleteSharedComments ( Oid  oid,
Oid  classoid 
)

Definition at line 373 of file comment.c.

References BTEqualStrategyNumber, CatalogTupleDelete(), ObjectIdGetDatum, RowExclusiveLock, ScanKeyInit(), SharedDescriptionObjIndexId, systable_beginscan(), systable_endscan(), systable_getnext(), HeapTupleData::t_self, table_close(), and table_open().

Referenced by dropdb(), DropRole(), and DropTableSpace().

374 {
375  Relation shdescription;
376  ScanKeyData skey[2];
377  SysScanDesc sd;
378  HeapTuple oldtuple;
379 
380  /* Use the index to search for all matching old tuples */
381 
382  ScanKeyInit(&skey[0],
383  Anum_pg_shdescription_objoid,
384  BTEqualStrategyNumber, F_OIDEQ,
385  ObjectIdGetDatum(oid));
386  ScanKeyInit(&skey[1],
387  Anum_pg_shdescription_classoid,
388  BTEqualStrategyNumber, F_OIDEQ,
389  ObjectIdGetDatum(classoid));
390 
391  shdescription = table_open(SharedDescriptionRelationId, RowExclusiveLock);
392 
393  sd = systable_beginscan(shdescription, SharedDescriptionObjIndexId, true,
394  NULL, 2, skey);
395 
396  while ((oldtuple = systable_getnext(sd)) != NULL)
397  CatalogTupleDelete(shdescription, &oldtuple->t_self);
398 
399  /* Done */
400 
401  systable_endscan(sd);
402  table_close(shdescription, RowExclusiveLock);
403 }
table_close
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:167
systable_endscan
void systable_endscan(SysScanDesc sysscan)
Definition: genam.c:595
SharedDescriptionObjIndexId
#define SharedDescriptionObjIndexId
Definition: pg_shdescription.h:63
CatalogTupleDelete
void CatalogTupleDelete(Relation heapRel, ItemPointer tid)
Definition: indexing.c:350
systable_beginscan
SysScanDesc systable_beginscan(Relation heapRelation, Oid indexId, bool indexOK, Snapshot snapshot, int nkeys, ScanKey key)
Definition: genam.c:383
systable_getnext
HeapTuple systable_getnext(SysScanDesc sysscan)
Definition: genam.c:502
ObjectIdGetDatum
#define ObjectIdGetDatum(X)
Definition: postgres.h:551
HeapTupleData::t_self
ItemPointerData t_self
Definition: htup.h:65
RowExclusiveLock
#define RowExclusiveLock
Definition: lockdefs.h:38
ScanKeyInit
void ScanKeyInit(ScanKey entry, AttrNumber attributeNumber, StrategyNumber strategy, RegProcedure procedure, Datum argument)
Definition: scankey.c:76
table_open
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
BTEqualStrategyNumber
#define BTEqualStrategyNumber
Definition: stratnum.h:31

◆ GetComment()

char* GetComment ( Oid  oid,
Oid  classoid,
int32  subid 
)

Definition at line 409 of file comment.c.

References AccessShareLock, BTEqualStrategyNumber, DescriptionObjIndexId, heap_getattr, Int32GetDatum, ObjectIdGetDatum, RelationGetDescr, ScanKeyInit(), systable_beginscan(), systable_endscan(), systable_getnext(), table_close(), table_open(), TextDatumGetCString, and value.

Referenced by ATPostAlterTypeParse(), expandTableLikeClause(), RebuildConstraintComment(), and transformTableLikeClause().

410 {
411  Relation description;
412  ScanKeyData skey[3];
413  SysScanDesc sd;
414  TupleDesc tupdesc;
415  HeapTuple tuple;
416  char *comment;
417 
418  /* Use the index to search for a matching old tuple */
419 
420  ScanKeyInit(&skey[0],
421  Anum_pg_description_objoid,
422  BTEqualStrategyNumber, F_OIDEQ,
423  ObjectIdGetDatum(oid));
424  ScanKeyInit(&skey[1],
425  Anum_pg_description_classoid,
426  BTEqualStrategyNumber, F_OIDEQ,
427  ObjectIdGetDatum(classoid));
428  ScanKeyInit(&skey[2],
429  Anum_pg_description_objsubid,
430  BTEqualStrategyNumber, F_INT4EQ,
431  Int32GetDatum(subid));
432 
433  description = table_open(DescriptionRelationId, AccessShareLock);
434  tupdesc = RelationGetDescr(description);
435 
436  sd = systable_beginscan(description, DescriptionObjIndexId, true,
437  NULL, 3, skey);
438 
439  comment = NULL;
440  while ((tuple = systable_getnext(sd)) != NULL)
441  {
442  Datum value;
443  bool isnull;
444 
445  /* Found the tuple, get description field */
446  value = heap_getattr(tuple, Anum_pg_description_description, tupdesc, &isnull);
447  if (!isnull)
448  comment = TextDatumGetCString(value);
449  break; /* Assume there can be only one match */
450  }
451 
452  systable_endscan(sd);
453 
454  /* Done */
455  table_close(description, AccessShareLock);
456 
457  return comment;
458 }
table_close
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:167
DescriptionObjIndexId
#define DescriptionObjIndexId
Definition: pg_description.h:69
systable_endscan
void systable_endscan(SysScanDesc sysscan)
Definition: genam.c:595
value
static struct @142 value
RelationGetDescr
#define RelationGetDescr(relation)
Definition: rel.h:495
AccessShareLock
#define AccessShareLock
Definition: lockdefs.h:36
systable_beginscan
SysScanDesc systable_beginscan(Relation heapRelation, Oid indexId, bool indexOK, Snapshot snapshot, int nkeys, ScanKey key)
Definition: genam.c:383
systable_getnext
HeapTuple systable_getnext(SysScanDesc sysscan)
Definition: genam.c:502
ObjectIdGetDatum
#define ObjectIdGetDatum(X)
Definition: postgres.h:551
heap_getattr
#define heap_getattr(tup, attnum, tupleDesc, isnull)
Definition: htup_details.h:761
TextDatumGetCString
#define TextDatumGetCString(d)
Definition: builtins.h:83
Datum
uintptr_t Datum
Definition: postgres.h:411
Int32GetDatum
#define Int32GetDatum(X)
Definition: postgres.h:523
ScanKeyInit
void ScanKeyInit(ScanKey entry, AttrNumber attributeNumber, StrategyNumber strategy, RegProcedure procedure, Datum argument)
Definition: scankey.c:76
table_open
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
BTEqualStrategyNumber
#define BTEqualStrategyNumber
Definition: stratnum.h:31