Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * tid.c
4 : * Functions for the built-in type tuple id
5 : *
6 : * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/utils/adt/tid.c
12 : *
13 : * NOTES
14 : * input routine largely stolen from boxin().
15 : *
16 : *-------------------------------------------------------------------------
17 : */
18 : #include "postgres.h"
19 :
20 : #include <math.h>
21 : #include <limits.h>
22 :
23 : #include "access/heapam.h"
24 : #include "access/sysattr.h"
25 : #include "access/tableam.h"
26 : #include "catalog/namespace.h"
27 : #include "catalog/pg_type.h"
28 : #include "libpq/pqformat.h"
29 : #include "miscadmin.h"
30 : #include "parser/parsetree.h"
31 : #include "utils/acl.h"
32 : #include "utils/builtins.h"
33 : #include "utils/hashutils.h"
34 : #include "utils/rel.h"
35 : #include "utils/snapmgr.h"
36 : #include "utils/varlena.h"
37 :
38 :
39 : #define DatumGetItemPointer(X) ((ItemPointer) DatumGetPointer(X))
40 : #define ItemPointerGetDatum(X) PointerGetDatum(X)
41 : #define PG_GETARG_ITEMPOINTER(n) DatumGetItemPointer(PG_GETARG_DATUM(n))
42 : #define PG_RETURN_ITEMPOINTER(x) return ItemPointerGetDatum(x)
43 :
44 : #define LDELIM '('
45 : #define RDELIM ')'
46 : #define DELIM ','
47 : #define NTIDARGS 2
48 :
49 : /* ----------------------------------------------------------------
50 : * tidin
51 : * ----------------------------------------------------------------
52 : */
53 : Datum
54 3166 : tidin(PG_FUNCTION_ARGS)
55 : {
56 3166 : char *str = PG_GETARG_CSTRING(0);
57 : char *p,
58 : *coord[NTIDARGS];
59 : int i;
60 : ItemPointer result;
61 : BlockNumber blockNumber;
62 : OffsetNumber offsetNumber;
63 : char *badp;
64 : int hold_offset;
65 :
66 14772 : for (i = 0, p = str; *p && i < NTIDARGS && *p != RDELIM; p++)
67 11606 : if (*p == DELIM || (*p == LDELIM && !i))
68 6332 : coord[i++] = p + 1;
69 :
70 3166 : if (i < NTIDARGS)
71 0 : ereport(ERROR,
72 : (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
73 : errmsg("invalid input syntax for type %s: \"%s\"",
74 : "tid", str)));
75 :
76 3166 : errno = 0;
77 3166 : blockNumber = strtoul(coord[0], &badp, 10);
78 3166 : if (errno || *badp != DELIM)
79 0 : ereport(ERROR,
80 : (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
81 : errmsg("invalid input syntax for type %s: \"%s\"",
82 : "tid", str)));
83 :
84 3166 : hold_offset = strtol(coord[1], &badp, 10);
85 3166 : if (errno || *badp != RDELIM ||
86 3166 : hold_offset > USHRT_MAX || hold_offset < 0)
87 0 : ereport(ERROR,
88 : (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
89 : errmsg("invalid input syntax for type %s: \"%s\"",
90 : "tid", str)));
91 :
92 3166 : offsetNumber = hold_offset;
93 :
94 3166 : result = (ItemPointer) palloc(sizeof(ItemPointerData));
95 :
96 3166 : ItemPointerSet(result, blockNumber, offsetNumber);
97 :
98 3166 : PG_RETURN_ITEMPOINTER(result);
99 : }
100 :
101 : /* ----------------------------------------------------------------
102 : * tidout
103 : * ----------------------------------------------------------------
104 : */
105 : Datum
106 3330 : tidout(PG_FUNCTION_ARGS)
107 : {
108 3330 : ItemPointer itemPtr = PG_GETARG_ITEMPOINTER(0);
109 : BlockNumber blockNumber;
110 : OffsetNumber offsetNumber;
111 : char buf[32];
112 :
113 3330 : blockNumber = ItemPointerGetBlockNumberNoCheck(itemPtr);
114 3330 : offsetNumber = ItemPointerGetOffsetNumberNoCheck(itemPtr);
115 :
116 : /* Perhaps someday we should output this as a record. */
117 3330 : snprintf(buf, sizeof(buf), "(%u,%u)", blockNumber, offsetNumber);
118 :
119 3330 : PG_RETURN_CSTRING(pstrdup(buf));
120 : }
121 :
122 : /*
123 : * tidrecv - converts external binary format to tid
124 : */
125 : Datum
126 0 : tidrecv(PG_FUNCTION_ARGS)
127 : {
128 0 : StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
129 : ItemPointer result;
130 : BlockNumber blockNumber;
131 : OffsetNumber offsetNumber;
132 :
133 0 : blockNumber = pq_getmsgint(buf, sizeof(blockNumber));
134 0 : offsetNumber = pq_getmsgint(buf, sizeof(offsetNumber));
135 :
136 0 : result = (ItemPointer) palloc(sizeof(ItemPointerData));
137 :
138 0 : ItemPointerSet(result, blockNumber, offsetNumber);
139 :
140 0 : PG_RETURN_ITEMPOINTER(result);
141 : }
142 :
143 : /*
144 : * tidsend - converts tid to binary format
145 : */
146 : Datum
147 0 : tidsend(PG_FUNCTION_ARGS)
148 : {
149 0 : ItemPointer itemPtr = PG_GETARG_ITEMPOINTER(0);
150 : StringInfoData buf;
151 :
152 0 : pq_begintypsend(&buf);
153 0 : pq_sendint32(&buf, ItemPointerGetBlockNumberNoCheck(itemPtr));
154 0 : pq_sendint16(&buf, ItemPointerGetOffsetNumberNoCheck(itemPtr));
155 0 : PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
156 : }
157 :
158 : /*****************************************************************************
159 : * PUBLIC ROUTINES *
160 : *****************************************************************************/
161 :
162 : Datum
163 7300106 : tideq(PG_FUNCTION_ARGS)
164 : {
165 7300106 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
166 7300106 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
167 :
168 7300106 : PG_RETURN_BOOL(ItemPointerCompare(arg1, arg2) == 0);
169 : }
170 :
171 : Datum
172 110 : tidne(PG_FUNCTION_ARGS)
173 : {
174 110 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
175 110 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
176 :
177 110 : PG_RETURN_BOOL(ItemPointerCompare(arg1, arg2) != 0);
178 : }
179 :
180 : Datum
181 2048 : tidlt(PG_FUNCTION_ARGS)
182 : {
183 2048 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
184 2048 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
185 :
186 2048 : PG_RETURN_BOOL(ItemPointerCompare(arg1, arg2) < 0);
187 : }
188 :
189 : Datum
190 1600 : tidle(PG_FUNCTION_ARGS)
191 : {
192 1600 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
193 1600 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
194 :
195 1600 : PG_RETURN_BOOL(ItemPointerCompare(arg1, arg2) <= 0);
196 : }
197 :
198 : Datum
199 9248 : tidgt(PG_FUNCTION_ARGS)
200 : {
201 9248 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
202 9248 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
203 :
204 9248 : PG_RETURN_BOOL(ItemPointerCompare(arg1, arg2) > 0);
205 : }
206 :
207 : Datum
208 1556 : tidge(PG_FUNCTION_ARGS)
209 : {
210 1556 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
211 1556 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
212 :
213 1556 : PG_RETURN_BOOL(ItemPointerCompare(arg1, arg2) >= 0);
214 : }
215 :
216 : Datum
217 207174 : bttidcmp(PG_FUNCTION_ARGS)
218 : {
219 207174 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
220 207174 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
221 :
222 207174 : PG_RETURN_INT32(ItemPointerCompare(arg1, arg2));
223 : }
224 :
225 : Datum
226 0 : tidlarger(PG_FUNCTION_ARGS)
227 : {
228 0 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
229 0 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
230 :
231 0 : PG_RETURN_ITEMPOINTER(ItemPointerCompare(arg1, arg2) >= 0 ? arg1 : arg2);
232 : }
233 :
234 : Datum
235 0 : tidsmaller(PG_FUNCTION_ARGS)
236 : {
237 0 : ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
238 0 : ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
239 :
240 0 : PG_RETURN_ITEMPOINTER(ItemPointerCompare(arg1, arg2) <= 0 ? arg1 : arg2);
241 : }
242 :
243 : Datum
244 80044 : hashtid(PG_FUNCTION_ARGS)
245 : {
246 80044 : ItemPointer key = PG_GETARG_ITEMPOINTER(0);
247 :
248 : /*
249 : * While you'll probably have a lot of trouble with a compiler that
250 : * insists on appending pad space to struct ItemPointerData, we can at
251 : * least make this code work, by not using sizeof(ItemPointerData).
252 : * Instead rely on knowing the sizes of the component fields.
253 : */
254 80044 : return hash_any((unsigned char *) key,
255 : sizeof(BlockIdData) + sizeof(OffsetNumber));
256 : }
257 :
258 : Datum
259 0 : hashtidextended(PG_FUNCTION_ARGS)
260 : {
261 0 : ItemPointer key = PG_GETARG_ITEMPOINTER(0);
262 0 : uint64 seed = PG_GETARG_INT64(1);
263 :
264 : /* As above */
265 0 : return hash_any_extended((unsigned char *) key,
266 : sizeof(BlockIdData) + sizeof(OffsetNumber),
267 : seed);
268 : }
269 :
270 :
271 : /*
272 : * Functions to get latest tid of a specified tuple.
273 : *
274 : * Maybe these implementations should be moved to another place
275 : */
276 :
277 : static ItemPointerData Current_last_tid = {{0, 0}, 0};
278 :
279 : void
280 11254480 : setLastTid(const ItemPointer tid)
281 : {
282 11254480 : Current_last_tid = *tid;
283 11254480 : }
284 :
285 : /*
286 : * Handle CTIDs of views.
287 : * CTID should be defined in the view and it must
288 : * correspond to the CTID of a base relation.
289 : */
290 : static Datum
291 0 : currtid_for_view(Relation viewrel, ItemPointer tid)
292 : {
293 0 : TupleDesc att = RelationGetDescr(viewrel);
294 : RuleLock *rulelock;
295 : RewriteRule *rewrite;
296 : int i,
297 0 : natts = att->natts,
298 0 : tididx = -1;
299 :
300 0 : for (i = 0; i < natts; i++)
301 : {
302 0 : Form_pg_attribute attr = TupleDescAttr(att, i);
303 :
304 0 : if (strcmp(NameStr(attr->attname), "ctid") == 0)
305 : {
306 0 : if (attr->atttypid != TIDOID)
307 0 : elog(ERROR, "ctid isn't of type TID");
308 0 : tididx = i;
309 0 : break;
310 : }
311 : }
312 0 : if (tididx < 0)
313 0 : elog(ERROR, "currtid cannot handle views with no CTID");
314 0 : rulelock = viewrel->rd_rules;
315 0 : if (!rulelock)
316 0 : elog(ERROR, "the view has no rules");
317 0 : for (i = 0; i < rulelock->numLocks; i++)
318 : {
319 0 : rewrite = rulelock->rules[i];
320 0 : if (rewrite->event == CMD_SELECT)
321 : {
322 : Query *query;
323 : TargetEntry *tle;
324 :
325 0 : if (list_length(rewrite->actions) != 1)
326 0 : elog(ERROR, "only one select rule is allowed in views");
327 0 : query = (Query *) linitial(rewrite->actions);
328 0 : tle = get_tle_by_resno(query->targetList, tididx + 1);
329 0 : if (tle && tle->expr && IsA(tle->expr, Var))
330 : {
331 0 : Var *var = (Var *) tle->expr;
332 : RangeTblEntry *rte;
333 :
334 0 : if (!IS_SPECIAL_VARNO(var->varno) &&
335 0 : var->varattno == SelfItemPointerAttributeNumber)
336 : {
337 0 : rte = rt_fetch(var->varno, query->rtable);
338 0 : if (rte)
339 : {
340 0 : table_close(viewrel, AccessShareLock);
341 0 : return DirectFunctionCall2(currtid_byreloid, ObjectIdGetDatum(rte->relid), PointerGetDatum(tid));
342 : }
343 : }
344 : }
345 0 : break;
346 : }
347 : }
348 0 : elog(ERROR, "currtid cannot handle this view");
349 : return (Datum) 0;
350 : }
351 :
352 : Datum
353 0 : currtid_byreloid(PG_FUNCTION_ARGS)
354 : {
355 0 : Oid reloid = PG_GETARG_OID(0);
356 0 : ItemPointer tid = PG_GETARG_ITEMPOINTER(1);
357 : ItemPointer result;
358 : Relation rel;
359 : AclResult aclresult;
360 : Snapshot snapshot;
361 : TableScanDesc scan;
362 :
363 0 : result = (ItemPointer) palloc(sizeof(ItemPointerData));
364 0 : if (!reloid)
365 : {
366 0 : *result = Current_last_tid;
367 0 : PG_RETURN_ITEMPOINTER(result);
368 : }
369 :
370 0 : rel = table_open(reloid, AccessShareLock);
371 :
372 0 : aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
373 : ACL_SELECT);
374 0 : if (aclresult != ACLCHECK_OK)
375 0 : aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
376 0 : RelationGetRelationName(rel));
377 :
378 0 : if (rel->rd_rel->relkind == RELKIND_VIEW)
379 0 : return currtid_for_view(rel, tid);
380 :
381 0 : ItemPointerCopy(tid, result);
382 :
383 0 : snapshot = RegisterSnapshot(GetLatestSnapshot());
384 0 : scan = table_beginscan(rel, snapshot, 0, NULL);
385 0 : table_tuple_get_latest_tid(scan, result);
386 0 : table_endscan(scan);
387 0 : UnregisterSnapshot(snapshot);
388 :
389 0 : table_close(rel, AccessShareLock);
390 :
391 0 : PG_RETURN_ITEMPOINTER(result);
392 : }
393 :
394 : Datum
395 0 : currtid_byrelname(PG_FUNCTION_ARGS)
396 : {
397 0 : text *relname = PG_GETARG_TEXT_PP(0);
398 0 : ItemPointer tid = PG_GETARG_ITEMPOINTER(1);
399 : ItemPointer result;
400 : RangeVar *relrv;
401 : Relation rel;
402 : AclResult aclresult;
403 : Snapshot snapshot;
404 : TableScanDesc scan;
405 :
406 0 : relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
407 0 : rel = table_openrv(relrv, AccessShareLock);
408 :
409 0 : aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
410 : ACL_SELECT);
411 0 : if (aclresult != ACLCHECK_OK)
412 0 : aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
413 0 : RelationGetRelationName(rel));
414 :
415 0 : if (rel->rd_rel->relkind == RELKIND_VIEW)
416 0 : return currtid_for_view(rel, tid);
417 :
418 0 : result = (ItemPointer) palloc(sizeof(ItemPointerData));
419 0 : ItemPointerCopy(tid, result);
420 :
421 0 : snapshot = RegisterSnapshot(GetLatestSnapshot());
422 0 : scan = table_beginscan(rel, snapshot, 0, NULL);
423 0 : table_tuple_get_latest_tid(scan, result);
424 0 : table_endscan(scan);
425 0 : UnregisterSnapshot(snapshot);
426 :
427 0 : table_close(rel, AccessShareLock);
428 :
429 0 : PG_RETURN_ITEMPOINTER(result);
430 : }
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