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amcmds.c
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1 /*-------------------------------------------------------------------------
2  *
3  * amcmds.c
4  * Routines for SQL commands that manipulate access methods.
5  *
6  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  *
10  * IDENTIFICATION
11  * src/backend/commands/amcmds.c
12  *-------------------------------------------------------------------------
13  */
14 #include "postgres.h"
15 
16 #include "access/htup_details.h"
17 #include "access/table.h"
18 #include "catalog/catalog.h"
19 #include "catalog/dependency.h"
20 #include "catalog/indexing.h"
21 #include "catalog/objectaccess.h"
22 #include "catalog/pg_am.h"
23 #include "catalog/pg_proc.h"
24 #include "catalog/pg_type.h"
25 #include "commands/defrem.h"
26 #include "miscadmin.h"
27 #include "parser/parse_func.h"
28 #include "utils/builtins.h"
29 #include "utils/lsyscache.h"
30 #include "utils/rel.h"
31 #include "utils/syscache.h"
32 
33 
34 static Oid lookup_am_handler_func(List *handler_name, char amtype);
35 static const char *get_am_type_string(char amtype);
36 
37 
38 /*
39  * CreateAccessMethod
40  * Registers a new access method.
41  */
44 {
45  Relation rel;
46  ObjectAddress myself;
47  ObjectAddress referenced;
48  Oid amoid;
49  Oid amhandler;
50  bool nulls[Natts_pg_am];
51  Datum values[Natts_pg_am];
52  HeapTuple tup;
53 
54  rel = table_open(AccessMethodRelationId, RowExclusiveLock);
55 
56  /* Must be super user */
57  if (!superuser())
58  ereport(ERROR,
59  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
60  errmsg("permission denied to create access method \"%s\"",
61  stmt->amname),
62  errhint("Must be superuser to create an access method.")));
63 
64  /* Check if name is used */
65  amoid = GetSysCacheOid1(AMNAME, Anum_pg_am_oid,
66  CStringGetDatum(stmt->amname));
67  if (OidIsValid(amoid))
68  {
69  ereport(ERROR,
71  errmsg("access method \"%s\" already exists",
72  stmt->amname)));
73  }
74 
75  /*
76  * Get the handler function oid, verifying the AM type while at it.
77  */
78  amhandler = lookup_am_handler_func(stmt->handler_name, stmt->amtype);
79 
80  /*
81  * Insert tuple into pg_am.
82  */
83  memset(values, 0, sizeof(values));
84  memset(nulls, false, sizeof(nulls));
85 
86  amoid = GetNewOidWithIndex(rel, AmOidIndexId, Anum_pg_am_oid);
87  values[Anum_pg_am_oid - 1] = ObjectIdGetDatum(amoid);
88  values[Anum_pg_am_amname - 1] =
90  values[Anum_pg_am_amhandler - 1] = ObjectIdGetDatum(amhandler);
91  values[Anum_pg_am_amtype - 1] = CharGetDatum(stmt->amtype);
92 
93  tup = heap_form_tuple(RelationGetDescr(rel), values, nulls);
94 
95  CatalogTupleInsert(rel, tup);
96  heap_freetuple(tup);
97 
98  myself.classId = AccessMethodRelationId;
99  myself.objectId = amoid;
100  myself.objectSubId = 0;
101 
102  /* Record dependency on handler function */
103  referenced.classId = ProcedureRelationId;
104  referenced.objectId = amhandler;
105  referenced.objectSubId = 0;
106 
107  recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
108 
109  recordDependencyOnCurrentExtension(&myself, false);
110 
111  InvokeObjectPostCreateHook(AccessMethodRelationId, amoid, 0);
112 
114 
115  return myself;
116 }
117 
118 /*
119  * get_am_type_oid
120  * Worker for various get_am_*_oid variants
121  *
122  * If missing_ok is false, throw an error if access method not found. If
123  * true, just return InvalidOid.
124  *
125  * If amtype is not '\0', an error is raised if the AM found is not of the
126  * given type.
127  */
128 static Oid
129 get_am_type_oid(const char *amname, char amtype, bool missing_ok)
130 {
131  HeapTuple tup;
132  Oid oid = InvalidOid;
133 
134  tup = SearchSysCache1(AMNAME, CStringGetDatum(amname));
135  if (HeapTupleIsValid(tup))
136  {
137  Form_pg_am amform = (Form_pg_am) GETSTRUCT(tup);
138 
139  if (amtype != '\0' &&
140  amform->amtype != amtype)
141  ereport(ERROR,
142  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
143  errmsg("access method \"%s\" is not of type %s",
144  NameStr(amform->amname),
145  get_am_type_string(amtype))));
146 
147  oid = amform->oid;
148  ReleaseSysCache(tup);
149  }
150 
151  if (!OidIsValid(oid) && !missing_ok)
152  ereport(ERROR,
153  (errcode(ERRCODE_UNDEFINED_OBJECT),
154  errmsg("access method \"%s\" does not exist", amname)));
155  return oid;
156 }
157 
158 /*
159  * get_index_am_oid - given an access method name, look up its OID
160  * and verify it corresponds to an index AM.
161  */
162 Oid
163 get_index_am_oid(const char *amname, bool missing_ok)
164 {
165  return get_am_type_oid(amname, AMTYPE_INDEX, missing_ok);
166 }
167 
168 /*
169  * get_table_am_oid - given an access method name, look up its OID
170  * and verify it corresponds to an table AM.
171  */
172 Oid
173 get_table_am_oid(const char *amname, bool missing_ok)
174 {
175  return get_am_type_oid(amname, AMTYPE_TABLE, missing_ok);
176 }
177 
178 /*
179  * get_am_oid - given an access method name, look up its OID.
180  * The type is not checked.
181  */
182 Oid
183 get_am_oid(const char *amname, bool missing_ok)
184 {
185  return get_am_type_oid(amname, '\0', missing_ok);
186 }
187 
188 /*
189  * get_am_name - given an access method OID name and type, look up its name.
190  */
191 char *
193 {
194  HeapTuple tup;
195  char *result = NULL;
196 
197  tup = SearchSysCache1(AMOID, ObjectIdGetDatum(amOid));
198  if (HeapTupleIsValid(tup))
199  {
200  Form_pg_am amform = (Form_pg_am) GETSTRUCT(tup);
201 
202  result = pstrdup(NameStr(amform->amname));
203  ReleaseSysCache(tup);
204  }
205  return result;
206 }
207 
208 /*
209  * Convert single-character access method type into string for error reporting.
210  */
211 static const char *
212 get_am_type_string(char amtype)
213 {
214  switch (amtype)
215  {
216  case AMTYPE_INDEX:
217  return "INDEX";
218  case AMTYPE_TABLE:
219  return "TABLE";
220  default:
221  /* shouldn't happen */
222  elog(ERROR, "invalid access method type '%c'", amtype);
223  return NULL; /* keep compiler quiet */
224  }
225 }
226 
227 /*
228  * Convert a handler function name to an Oid. If the return type of the
229  * function doesn't match the given AM type, an error is raised.
230  *
231  * This function either return valid function Oid or throw an error.
232  */
233 static Oid
234 lookup_am_handler_func(List *handler_name, char amtype)
235 {
236  Oid handlerOid;
237  Oid funcargtypes[1] = {INTERNALOID};
238  Oid expectedType = InvalidOid;
239 
240  if (handler_name == NIL)
241  ereport(ERROR,
242  (errcode(ERRCODE_UNDEFINED_FUNCTION),
243  errmsg("handler function is not specified")));
244 
245  /* handlers have one argument of type internal */
246  handlerOid = LookupFuncName(handler_name, 1, funcargtypes, false);
247 
248  /* check that handler has the correct return type */
249  switch (amtype)
250  {
251  case AMTYPE_INDEX:
252  expectedType = INDEX_AM_HANDLEROID;
253  break;
254  case AMTYPE_TABLE:
255  expectedType = TABLE_AM_HANDLEROID;
256  break;
257  default:
258  elog(ERROR, "unrecognized access method type \"%c\"", amtype);
259  }
260 
261  if (get_func_rettype(handlerOid) != expectedType)
262  ereport(ERROR,
263  (errcode(ERRCODE_WRONG_OBJECT_TYPE),
264  errmsg("function %s must return type %s",
265  get_func_name(handlerOid),
266  format_type_extended(expectedType, -1, 0))));
267 
268  return handlerOid;
269 }
#define NIL
Definition: pg_list.h:65
Oid GetNewOidWithIndex(Relation relation, Oid indexId, AttrNumber oidcolumn)
Definition: catalog.c:317
Datum namein(PG_FUNCTION_ARGS)
Definition: name.c:48
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:167
int errhint(const char *fmt,...)
Definition: elog.c:1068
#define GETSTRUCT(TUP)
Definition: htup_details.h:655
static const char * get_am_type_string(char amtype)
Definition: amcmds.c:212
static Oid lookup_am_handler_func(List *handler_name, char amtype)
Definition: amcmds.c:234
Oid get_am_oid(const char *amname, bool missing_ok)
Definition: amcmds.c:183
#define InvokeObjectPostCreateHook(classId, objectId, subId)
Definition: objectaccess.h:151
Definition: syscache.h:36
#define RelationGetDescr(relation)
Definition: rel.h:482
#define GetSysCacheOid1(cacheId, oidcol, key1)
Definition: syscache.h:192
char * pstrdup(const char *in)
Definition: mcxt.c:1187
static Oid get_am_type_oid(const char *amname, char amtype, bool missing_ok)
Definition: amcmds.c:129
int errcode(int sqlerrcode)
Definition: elog.c:610
bool superuser(void)
Definition: superuser.c:46
void recordDependencyOn(const ObjectAddress *depender, const ObjectAddress *referenced, DependencyType behavior)
Definition: pg_depend.c:43
HeapTuple heap_form_tuple(TupleDesc tupleDescriptor, Datum *values, bool *isnull)
Definition: heaptuple.c:1020
#define DirectFunctionCall1(func, arg1)
Definition: fmgr.h:624
void heap_freetuple(HeapTuple htup)
Definition: heaptuple.c:1338
unsigned int Oid
Definition: postgres_ext.h:31
#define OidIsValid(objectId)
Definition: c.h:652
Oid get_func_rettype(Oid funcid)
Definition: lsyscache.c:1567
#define ObjectIdGetDatum(X)
Definition: postgres.h:507
#define ERROR
Definition: elog.h:43
char * get_func_name(Oid funcid)
Definition: lsyscache.c:1520
Oid LookupFuncName(List *funcname, int nargs, const Oid *argtypes, bool missing_ok)
Definition: parse_func.c:2103
char * amname
Definition: parsenodes.h:2420
Oid get_index_am_oid(const char *amname, bool missing_ok)
Definition: amcmds.c:163
char * get_am_name(Oid amOid)
Definition: amcmds.c:192
#define RowExclusiveLock
Definition: lockdefs.h:38
#define CStringGetDatum(X)
Definition: postgres.h:578
HeapTuple SearchSysCache1(int cacheId, Datum key1)
Definition: syscache.c:1116
uintptr_t Datum
Definition: postgres.h:367
void ReleaseSysCache(HeapTuple tuple)
Definition: syscache.c:1164
List * handler_name
Definition: parsenodes.h:2421
#define InvalidOid
Definition: postgres_ext.h:36
#define ereport(elevel,...)
Definition: elog.h:144
#define HeapTupleIsValid(tuple)
Definition: htup.h:78
Oid get_table_am_oid(const char *amname, bool missing_ok)
Definition: amcmds.c:173
void recordDependencyOnCurrentExtension(const ObjectAddress *object, bool isReplace)
Definition: pg_depend.c:180
char * format_type_extended(Oid type_oid, int32 typemod, bits16 flags)
Definition: format_type.c:111
#define CharGetDatum(X)
Definition: postgres.h:416
static Datum values[MAXATTR]
Definition: bootstrap.c:165
FormData_pg_am * Form_pg_am
Definition: pg_am.h:48
int errmsg(const char *fmt,...)
Definition: elog.c:821
#define elog(elevel,...)
Definition: elog.h:214
#define NameStr(name)
Definition: c.h:623
#define AmOidIndexId
Definition: indexing.h:85
ObjectAddress CreateAccessMethod(CreateAmStmt *stmt)
Definition: amcmds.c:43
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
#define ERRCODE_DUPLICATE_OBJECT
Definition: streamutil.c:32
Definition: pg_list.h:50
void CatalogTupleInsert(Relation heapRel, HeapTuple tup)
Definition: indexing.c:221