Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * pg_enum.c
4 : * routines to support manipulation of the pg_enum relation
5 : *
6 : * Copyright (c) 2006-2026, PostgreSQL Global Development Group
7 : *
8 : *
9 : * IDENTIFICATION
10 : * src/backend/catalog/pg_enum.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 : #include "postgres.h"
15 :
16 : #include "access/genam.h"
17 : #include "access/htup_details.h"
18 : #include "access/table.h"
19 : #include "access/xact.h"
20 : #include "catalog/binary_upgrade.h"
21 : #include "catalog/catalog.h"
22 : #include "catalog/indexing.h"
23 : #include "catalog/pg_enum.h"
24 : #include "catalog/pg_type.h"
25 : #include "miscadmin.h"
26 : #include "nodes/value.h"
27 : #include "storage/lmgr.h"
28 : #include "utils/builtins.h"
29 : #include "utils/catcache.h"
30 : #include "utils/fmgroids.h"
31 : #include "utils/hsearch.h"
32 : #include "utils/memutils.h"
33 : #include "utils/syscache.h"
34 :
35 : /* Potentially set by pg_upgrade_support functions */
36 : Oid binary_upgrade_next_pg_enum_oid = InvalidOid;
37 :
38 : /*
39 : * We keep two transaction-lifespan hash tables, one containing the OIDs
40 : * of enum types made in the current transaction, and one containing the
41 : * OIDs of enum values created during the current transaction by
42 : * AddEnumLabel (but only if their enum type is not in the first hash).
43 : *
44 : * We disallow using enum values in the second hash until the transaction is
45 : * committed; otherwise, they might get into indexes where we can't clean
46 : * them up, and then if the transaction rolls back we have a broken index.
47 : * (See comments for check_safe_enum_use() in enum.c.) Values created by
48 : * EnumValuesCreate are *not* entered into the table; we assume those are
49 : * created during CREATE TYPE, so they can't go away unless the enum type
50 : * itself does.
51 : *
52 : * The motivation for treating enum values as safe if their type OID is
53 : * in the first hash is to allow CREATE TYPE AS ENUM; ALTER TYPE ADD VALUE;
54 : * followed by a use of the value in the same transaction. This pattern
55 : * is really just as safe as creating the value during CREATE TYPE.
56 : * We need to support this because pg_dump in binary upgrade mode produces
57 : * commands like that. But currently we only support it when the commands
58 : * are at the outermost transaction level, which is as much as we need for
59 : * pg_dump. We could track subtransaction nesting of the commands to
60 : * analyze things more precisely, but for now we don't bother.
61 : */
62 : static HTAB *uncommitted_enum_types = NULL;
63 : static HTAB *uncommitted_enum_values = NULL;
64 :
65 : static void init_uncommitted_enum_types(void);
66 : static void init_uncommitted_enum_values(void);
67 : static bool EnumTypeUncommitted(Oid typ_id);
68 : static void RenumberEnumType(Relation pg_enum, HeapTuple *existing, int nelems);
69 : static int sort_order_cmp(const void *p1, const void *p2);
70 :
71 :
72 : /*
73 : * EnumValuesCreate
74 : * Create an entry in pg_enum for each of the supplied enum values.
75 : *
76 : * vals is a list of String values.
77 : *
78 : * We assume that this is called only by CREATE TYPE AS ENUM, and that it
79 : * will be called even if the vals list is empty. So we can enter the
80 : * enum type's OID into uncommitted_enum_types here, rather than needing
81 : * another entry point to do it.
82 : */
83 : void
84 221 : EnumValuesCreate(Oid enumTypeOid, List *vals)
85 : {
86 : Relation pg_enum;
87 : Oid *oids;
88 : int elemno,
89 : num_elems;
90 : ListCell *lc;
91 221 : int slotCount = 0;
92 : int nslots;
93 : CatalogIndexState indstate;
94 : TupleTableSlot **slot;
95 :
96 : /*
97 : * Remember the type OID as being made in the current transaction, but not
98 : * if we're in a subtransaction. (We could remember the OID anyway, in
99 : * case a subsequent ALTER ADD VALUE occurs at outer level. But that
100 : * usage pattern seems unlikely enough that we'd probably just be wasting
101 : * hashtable maintenance effort.)
102 : */
103 221 : if (GetCurrentTransactionNestLevel() == 1)
104 : {
105 221 : if (uncommitted_enum_types == NULL)
106 218 : init_uncommitted_enum_types();
107 221 : (void) hash_search(uncommitted_enum_types, &enumTypeOid,
108 : HASH_ENTER, NULL);
109 : }
110 :
111 221 : num_elems = list_length(vals);
112 :
113 221 : pg_enum = table_open(EnumRelationId, RowExclusiveLock);
114 :
115 : /*
116 : * Allocate OIDs for the enum's members.
117 : *
118 : * While this method does not absolutely guarantee that we generate no
119 : * duplicate OIDs (since we haven't entered each oid into the table before
120 : * allocating the next), trouble could only occur if the OID counter wraps
121 : * all the way around before we finish. Which seems unlikely.
122 : */
123 221 : oids = palloc_array(Oid, num_elems);
124 :
125 125525 : for (elemno = 0; elemno < num_elems; elemno++)
126 : {
127 : /*
128 : * We assign even-numbered OIDs to all the new enum labels. This
129 : * tells the comparison functions the OIDs are in the correct sort
130 : * order and can be compared directly.
131 : */
132 : Oid new_oid;
133 :
134 : do
135 : {
136 250569 : new_oid = GetNewOidWithIndex(pg_enum, EnumOidIndexId,
137 : Anum_pg_enum_oid);
138 250569 : } while (new_oid & 1);
139 125304 : oids[elemno] = new_oid;
140 : }
141 :
142 : /* sort them, just in case OID counter wrapped from high to low */
143 221 : qsort(oids, num_elems, sizeof(Oid), oid_cmp);
144 :
145 : /* and make the entries */
146 221 : indstate = CatalogOpenIndexes(pg_enum);
147 :
148 : /* allocate the slots to use and initialize them */
149 221 : nslots = Min(num_elems,
150 : MAX_CATALOG_MULTI_INSERT_BYTES / sizeof(FormData_pg_enum));
151 221 : slot = palloc_array(TupleTableSlot *, nslots);
152 108275 : for (int i = 0; i < nslots; i++)
153 108054 : slot[i] = MakeSingleTupleTableSlot(RelationGetDescr(pg_enum),
154 : &TTSOpsHeapTuple);
155 :
156 221 : elemno = 0;
157 125522 : foreach(lc, vals)
158 : {
159 125304 : char *lab = strVal(lfirst(lc));
160 125304 : Name enumlabel = palloc0(NAMEDATALEN);
161 : ListCell *lc2;
162 :
163 : /*
164 : * labels are stored in a name field, for easier syscache lookup, so
165 : * check the length to make sure it's within range.
166 : */
167 125304 : if (strlen(lab) > (NAMEDATALEN - 1))
168 0 : ereport(ERROR,
169 : (errcode(ERRCODE_INVALID_NAME),
170 : errmsg("invalid enum label \"%s\"", lab),
171 : errdetail("Labels must be %d bytes or less.",
172 : NAMEDATALEN - 1)));
173 :
174 : /*
175 : * Check for duplicate labels. The unique index on pg_enum would catch
176 : * that anyway, but we prefer a friendlier error message.
177 : */
178 62563351 : foreach(lc2, vals)
179 : {
180 : /* Only need to compare lc to earlier entries */
181 62563351 : if (lc2 == lc)
182 125301 : break;
183 :
184 62438050 : if (strcmp(lab, strVal(lfirst(lc2))) == 0)
185 3 : ereport(ERROR,
186 : (errcode(ERRCODE_DUPLICATE_OBJECT),
187 : errmsg("enum label \"%s\" used more than once",
188 : lab)));
189 : }
190 :
191 : /* OK, construct a tuple for this label */
192 125301 : ExecClearTuple(slot[slotCount]);
193 :
194 125301 : memset(slot[slotCount]->tts_isnull, false,
195 125301 : slot[slotCount]->tts_tupleDescriptor->natts * sizeof(bool));
196 :
197 125301 : slot[slotCount]->tts_values[Anum_pg_enum_oid - 1] = ObjectIdGetDatum(oids[elemno]);
198 125301 : slot[slotCount]->tts_values[Anum_pg_enum_enumtypid - 1] = ObjectIdGetDatum(enumTypeOid);
199 125301 : slot[slotCount]->tts_values[Anum_pg_enum_enumsortorder - 1] = Float4GetDatum(elemno + 1);
200 :
201 125301 : namestrcpy(enumlabel, lab);
202 125301 : slot[slotCount]->tts_values[Anum_pg_enum_enumlabel - 1] = NameGetDatum(enumlabel);
203 :
204 125301 : ExecStoreVirtualTuple(slot[slotCount]);
205 125301 : slotCount++;
206 :
207 : /* if slots are full, insert a batch of tuples */
208 125301 : if (slotCount == nslots)
209 : {
210 214 : CatalogTuplesMultiInsertWithInfo(pg_enum, slot, slotCount,
211 : indstate);
212 214 : slotCount = 0;
213 : }
214 :
215 125301 : elemno++;
216 : }
217 :
218 : /* Insert any tuples left in the buffer */
219 218 : if (slotCount > 0)
220 125 : CatalogTuplesMultiInsertWithInfo(pg_enum, slot, slotCount,
221 : indstate);
222 :
223 : /* clean up */
224 218 : pfree(oids);
225 108263 : for (int i = 0; i < nslots; i++)
226 108045 : ExecDropSingleTupleTableSlot(slot[i]);
227 218 : CatalogCloseIndexes(indstate);
228 218 : table_close(pg_enum, RowExclusiveLock);
229 218 : }
230 :
231 :
232 : /*
233 : * EnumValuesDelete
234 : * Remove all the pg_enum entries for the specified enum type.
235 : */
236 : void
237 162 : EnumValuesDelete(Oid enumTypeOid)
238 : {
239 : Relation pg_enum;
240 : ScanKeyData key[1];
241 : SysScanDesc scan;
242 : HeapTuple tup;
243 :
244 162 : pg_enum = table_open(EnumRelationId, RowExclusiveLock);
245 :
246 162 : ScanKeyInit(&key[0],
247 : Anum_pg_enum_enumtypid,
248 : BTEqualStrategyNumber, F_OIDEQ,
249 : ObjectIdGetDatum(enumTypeOid));
250 :
251 162 : scan = systable_beginscan(pg_enum, EnumTypIdLabelIndexId, true,
252 : NULL, 1, key);
253 :
254 125276 : while (HeapTupleIsValid(tup = systable_getnext(scan)))
255 : {
256 125114 : CatalogTupleDelete(pg_enum, &tup->t_self);
257 : }
258 :
259 162 : systable_endscan(scan);
260 :
261 162 : table_close(pg_enum, RowExclusiveLock);
262 162 : }
263 :
264 : /*
265 : * Initialize the uncommitted enum types table for this transaction.
266 : */
267 : static void
268 218 : init_uncommitted_enum_types(void)
269 : {
270 : HASHCTL hash_ctl;
271 :
272 218 : hash_ctl.keysize = sizeof(Oid);
273 218 : hash_ctl.entrysize = sizeof(Oid);
274 218 : hash_ctl.hcxt = TopTransactionContext;
275 218 : uncommitted_enum_types = hash_create("Uncommitted enum types",
276 : 32,
277 : &hash_ctl,
278 : HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
279 218 : }
280 :
281 : /*
282 : * Initialize the uncommitted enum values table for this transaction.
283 : */
284 : static void
285 118 : init_uncommitted_enum_values(void)
286 : {
287 : HASHCTL hash_ctl;
288 :
289 118 : hash_ctl.keysize = sizeof(Oid);
290 118 : hash_ctl.entrysize = sizeof(Oid);
291 118 : hash_ctl.hcxt = TopTransactionContext;
292 118 : uncommitted_enum_values = hash_create("Uncommitted enum values",
293 : 32,
294 : &hash_ctl,
295 : HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
296 118 : }
297 :
298 : /*
299 : * AddEnumLabel
300 : * Add a new label to the enum set. By default it goes at
301 : * the end, but the user can choose to place it before or
302 : * after any existing set member.
303 : */
304 : void
305 186 : AddEnumLabel(Oid enumTypeOid,
306 : const char *newVal,
307 : const char *neighbor,
308 : bool newValIsAfter,
309 : bool skipIfExists)
310 : {
311 : Relation pg_enum;
312 : Oid newOid;
313 : Datum values[Natts_pg_enum];
314 : bool nulls[Natts_pg_enum];
315 : NameData enumlabel;
316 : HeapTuple enum_tup;
317 : float4 newelemorder;
318 : HeapTuple *existing;
319 : CatCList *list;
320 : int nelems;
321 : int i;
322 :
323 : /* check length of new label is ok */
324 186 : if (strlen(newVal) > (NAMEDATALEN - 1))
325 3 : ereport(ERROR,
326 : (errcode(ERRCODE_INVALID_NAME),
327 : errmsg("invalid enum label \"%s\"", newVal),
328 : errdetail("Labels must be %d bytes or less.",
329 : NAMEDATALEN - 1)));
330 :
331 : /*
332 : * Acquire a lock on the enum type, which we won't release until commit.
333 : * This ensures that two backends aren't concurrently modifying the same
334 : * enum type. Without that, we couldn't be sure to get a consistent view
335 : * of the enum members via the syscache. Note that this does not block
336 : * other backends from inspecting the type; see comments for
337 : * RenumberEnumType.
338 : */
339 183 : LockDatabaseObject(TypeRelationId, enumTypeOid, 0, ExclusiveLock);
340 :
341 : /*
342 : * Check if label is already in use. The unique index on pg_enum would
343 : * catch this anyway, but we prefer a friendlier error message, and
344 : * besides we need a check to support IF NOT EXISTS.
345 : */
346 183 : enum_tup = SearchSysCache2(ENUMTYPOIDNAME,
347 : ObjectIdGetDatum(enumTypeOid),
348 : CStringGetDatum(newVal));
349 183 : if (HeapTupleIsValid(enum_tup))
350 : {
351 6 : ReleaseSysCache(enum_tup);
352 6 : if (skipIfExists)
353 : {
354 3 : ereport(NOTICE,
355 : (errcode(ERRCODE_DUPLICATE_OBJECT),
356 : errmsg("enum label \"%s\" already exists, skipping",
357 : newVal)));
358 59 : return;
359 : }
360 : else
361 3 : ereport(ERROR,
362 : (errcode(ERRCODE_DUPLICATE_OBJECT),
363 : errmsg("enum label \"%s\" already exists",
364 : newVal)));
365 : }
366 :
367 177 : pg_enum = table_open(EnumRelationId, RowExclusiveLock);
368 :
369 : /* If we have to renumber the existing members, we restart from here */
370 180 : restart:
371 :
372 : /* Get the list of existing members of the enum */
373 180 : list = SearchSysCacheList1(ENUMTYPOIDNAME,
374 : ObjectIdGetDatum(enumTypeOid));
375 180 : nelems = list->n_members;
376 :
377 : /* Sort the existing members by enumsortorder */
378 180 : existing = palloc_array(HeapTuple, nelems);
379 2447 : for (i = 0; i < nelems; i++)
380 2267 : existing[i] = &(list->members[i]->tuple);
381 :
382 180 : qsort(existing, nelems, sizeof(HeapTuple), sort_order_cmp);
383 :
384 180 : if (neighbor == NULL)
385 : {
386 : /*
387 : * Put the new label at the end of the list. No change to existing
388 : * tuples is required.
389 : */
390 68 : if (nelems > 0)
391 : {
392 64 : Form_pg_enum en = (Form_pg_enum) GETSTRUCT(existing[nelems - 1]);
393 :
394 64 : newelemorder = en->enumsortorder + 1;
395 : }
396 : else
397 4 : newelemorder = 1;
398 : }
399 : else
400 : {
401 : /* BEFORE or AFTER was specified */
402 : int nbr_index;
403 : int other_nbr_index;
404 : Form_pg_enum nbr_en;
405 : Form_pg_enum other_nbr_en;
406 :
407 : /* Locate the neighbor element */
408 1646 : for (nbr_index = 0; nbr_index < nelems; nbr_index++)
409 : {
410 1643 : Form_pg_enum en = (Form_pg_enum) GETSTRUCT(existing[nbr_index]);
411 :
412 1643 : if (strcmp(NameStr(en->enumlabel), neighbor) == 0)
413 109 : break;
414 : }
415 112 : if (nbr_index >= nelems)
416 3 : ereport(ERROR,
417 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
418 : errmsg("\"%s\" is not an existing enum label",
419 : neighbor)));
420 109 : nbr_en = (Form_pg_enum) GETSTRUCT(existing[nbr_index]);
421 :
422 : /*
423 : * Attempt to assign an appropriate enumsortorder value: one less than
424 : * the smallest member, one more than the largest member, or halfway
425 : * between two existing members.
426 : *
427 : * In the "halfway" case, because of the finite precision of float4,
428 : * we might compute a value that's actually equal to one or the other
429 : * of its neighbors. In that case we renumber the existing members
430 : * and try again.
431 : */
432 109 : if (newValIsAfter)
433 8 : other_nbr_index = nbr_index + 1;
434 : else
435 101 : other_nbr_index = nbr_index - 1;
436 :
437 109 : if (other_nbr_index < 0)
438 4 : newelemorder = nbr_en->enumsortorder - 1;
439 105 : else if (other_nbr_index >= nelems)
440 4 : newelemorder = nbr_en->enumsortorder + 1;
441 : else
442 : {
443 : /*
444 : * The midpoint value computed here has to be rounded to float4
445 : * precision, else our equality comparisons against the adjacent
446 : * values are meaningless. The most portable way of forcing that
447 : * to happen with non-C-standard-compliant compilers is to store
448 : * it into a volatile variable.
449 : */
450 : volatile float4 midpoint;
451 :
452 101 : other_nbr_en = (Form_pg_enum) GETSTRUCT(existing[other_nbr_index]);
453 101 : midpoint = (nbr_en->enumsortorder +
454 101 : other_nbr_en->enumsortorder) / 2;
455 :
456 101 : if (midpoint == nbr_en->enumsortorder ||
457 98 : midpoint == other_nbr_en->enumsortorder)
458 : {
459 3 : RenumberEnumType(pg_enum, existing, nelems);
460 : /* Clean up and start over */
461 3 : pfree(existing);
462 3 : ReleaseCatCacheList(list);
463 3 : goto restart;
464 : }
465 :
466 98 : newelemorder = midpoint;
467 : }
468 : }
469 :
470 : /* Get a new OID for the new label */
471 174 : if (IsBinaryUpgrade)
472 : {
473 50 : if (!OidIsValid(binary_upgrade_next_pg_enum_oid))
474 0 : ereport(ERROR,
475 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
476 : errmsg("pg_enum OID value not set when in binary upgrade mode")));
477 :
478 : /*
479 : * Use binary-upgrade override for pg_enum.oid, if supplied. During
480 : * binary upgrade, all pg_enum.oid's are set this way so they are
481 : * guaranteed to be consistent.
482 : */
483 50 : if (neighbor != NULL)
484 0 : ereport(ERROR,
485 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
486 : errmsg("ALTER TYPE ADD BEFORE/AFTER is incompatible with binary upgrade")));
487 :
488 50 : newOid = binary_upgrade_next_pg_enum_oid;
489 50 : binary_upgrade_next_pg_enum_oid = InvalidOid;
490 : }
491 : else
492 : {
493 : /*
494 : * Normal case: we need to allocate a new Oid for the value.
495 : *
496 : * We want to give the new element an even-numbered Oid if it's safe,
497 : * which is to say it compares correctly to all pre-existing even
498 : * numbered Oids in the enum. Otherwise, we must give it an odd Oid.
499 : */
500 : for (;;)
501 97 : {
502 : bool sorts_ok;
503 :
504 : /* Get a new OID (different from all existing pg_enum tuples) */
505 221 : newOid = GetNewOidWithIndex(pg_enum, EnumOidIndexId,
506 : Anum_pg_enum_oid);
507 :
508 : /*
509 : * Detect whether it sorts correctly relative to existing
510 : * even-numbered labels of the enum. We can ignore existing
511 : * labels with odd Oids, since a comparison involving one of those
512 : * will not take the fast path anyway.
513 : */
514 221 : sorts_ok = true;
515 2880 : for (i = 0; i < nelems; i++)
516 : {
517 2840 : HeapTuple exists_tup = existing[i];
518 2840 : Form_pg_enum exists_en = (Form_pg_enum) GETSTRUCT(exists_tup);
519 2840 : Oid exists_oid = exists_en->oid;
520 :
521 2840 : if (exists_oid & 1)
522 2362 : continue; /* ignore odd Oids */
523 :
524 478 : if (exists_en->enumsortorder < newelemorder)
525 : {
526 : /* should sort before */
527 297 : if (exists_oid >= newOid)
528 : {
529 0 : sorts_ok = false;
530 0 : break;
531 : }
532 : }
533 : else
534 : {
535 : /* should sort after */
536 181 : if (exists_oid <= newOid)
537 : {
538 181 : sorts_ok = false;
539 181 : break;
540 : }
541 : }
542 : }
543 :
544 221 : if (sorts_ok)
545 : {
546 : /* If it's even and sorts OK, we're done. */
547 40 : if ((newOid & 1) == 0)
548 22 : break;
549 :
550 : /*
551 : * If it's odd, and sorts OK, loop back to get another OID and
552 : * try again. Probably, the next available even OID will sort
553 : * correctly too, so it's worth trying.
554 : */
555 : }
556 : else
557 : {
558 : /*
559 : * If it's odd, and does not sort correctly, we're done.
560 : * (Probably, the next available even OID would sort
561 : * incorrectly too, so no point in trying again.)
562 : */
563 181 : if (newOid & 1)
564 102 : break;
565 :
566 : /*
567 : * If it's even, and does not sort correctly, loop back to get
568 : * another OID and try again. (We *must* reject this case.)
569 : */
570 : }
571 : }
572 : }
573 :
574 : /* Done with info about existing members */
575 174 : pfree(existing);
576 174 : ReleaseCatCacheList(list);
577 :
578 : /* Create the new pg_enum entry */
579 174 : memset(nulls, false, sizeof(nulls));
580 174 : values[Anum_pg_enum_oid - 1] = ObjectIdGetDatum(newOid);
581 174 : values[Anum_pg_enum_enumtypid - 1] = ObjectIdGetDatum(enumTypeOid);
582 174 : values[Anum_pg_enum_enumsortorder - 1] = Float4GetDatum(newelemorder);
583 174 : namestrcpy(&enumlabel, newVal);
584 174 : values[Anum_pg_enum_enumlabel - 1] = NameGetDatum(&enumlabel);
585 174 : enum_tup = heap_form_tuple(RelationGetDescr(pg_enum), values, nulls);
586 174 : CatalogTupleInsert(pg_enum, enum_tup);
587 174 : heap_freetuple(enum_tup);
588 :
589 174 : table_close(pg_enum, RowExclusiveLock);
590 :
591 : /*
592 : * If the enum type itself is uncommitted, we need not enter the new enum
593 : * value into uncommitted_enum_values, because the type won't survive if
594 : * the value doesn't. (This is basically the same reasoning as for values
595 : * made directly by CREATE TYPE AS ENUM.) However, apply this rule only
596 : * when we are not inside a subtransaction; if we're more deeply nested
597 : * than the CREATE TYPE then the conclusion doesn't hold. We could expend
598 : * more effort to track the subtransaction level of CREATE TYPE, but for
599 : * now we're only concerned about making the world safe for pg_dump in
600 : * binary upgrade mode, and that won't use subtransactions.
601 : */
602 348 : if (GetCurrentTransactionNestLevel() == 1 &&
603 174 : EnumTypeUncommitted(enumTypeOid))
604 56 : return;
605 :
606 : /* Set up the uncommitted values table if not already done in this tx */
607 118 : if (uncommitted_enum_values == NULL)
608 118 : init_uncommitted_enum_values();
609 :
610 : /* Add the new value to the table */
611 118 : (void) hash_search(uncommitted_enum_values, &newOid, HASH_ENTER, NULL);
612 : }
613 :
614 :
615 : /*
616 : * RenameEnumLabel
617 : * Rename a label in an enum set.
618 : */
619 : void
620 12 : RenameEnumLabel(Oid enumTypeOid,
621 : const char *oldVal,
622 : const char *newVal)
623 : {
624 : Relation pg_enum;
625 : HeapTuple enum_tup;
626 : Form_pg_enum en;
627 : CatCList *list;
628 : int nelems;
629 : HeapTuple old_tup;
630 : bool found_new;
631 : int i;
632 :
633 : /* check length of new label is ok */
634 12 : if (strlen(newVal) > (NAMEDATALEN - 1))
635 0 : ereport(ERROR,
636 : (errcode(ERRCODE_INVALID_NAME),
637 : errmsg("invalid enum label \"%s\"", newVal),
638 : errdetail("Labels must be %d bytes or less.",
639 : NAMEDATALEN - 1)));
640 :
641 : /*
642 : * Acquire a lock on the enum type, which we won't release until commit.
643 : * This ensures that two backends aren't concurrently modifying the same
644 : * enum type. Since we are not changing the type's sort order, this is
645 : * probably not really necessary, but there seems no reason not to take
646 : * the lock to be sure.
647 : */
648 12 : LockDatabaseObject(TypeRelationId, enumTypeOid, 0, ExclusiveLock);
649 :
650 12 : pg_enum = table_open(EnumRelationId, RowExclusiveLock);
651 :
652 : /* Get the list of existing members of the enum */
653 12 : list = SearchSysCacheList1(ENUMTYPOIDNAME,
654 : ObjectIdGetDatum(enumTypeOid));
655 12 : nelems = list->n_members;
656 :
657 : /*
658 : * Locate the element to rename and check if the new label is already in
659 : * use. (The unique index on pg_enum would catch that anyway, but we
660 : * prefer a friendlier error message.)
661 : */
662 12 : old_tup = NULL;
663 12 : found_new = false;
664 72 : for (i = 0; i < nelems; i++)
665 : {
666 60 : enum_tup = &(list->members[i]->tuple);
667 60 : en = (Form_pg_enum) GETSTRUCT(enum_tup);
668 60 : if (strcmp(NameStr(en->enumlabel), oldVal) == 0)
669 9 : old_tup = enum_tup;
670 60 : if (strcmp(NameStr(en->enumlabel), newVal) == 0)
671 6 : found_new = true;
672 : }
673 12 : if (!old_tup)
674 3 : ereport(ERROR,
675 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
676 : errmsg("\"%s\" is not an existing enum label",
677 : oldVal)));
678 9 : if (found_new)
679 3 : ereport(ERROR,
680 : (errcode(ERRCODE_DUPLICATE_OBJECT),
681 : errmsg("enum label \"%s\" already exists",
682 : newVal)));
683 :
684 : /* OK, make a writable copy of old tuple */
685 6 : enum_tup = heap_copytuple(old_tup);
686 6 : en = (Form_pg_enum) GETSTRUCT(enum_tup);
687 :
688 6 : ReleaseCatCacheList(list);
689 :
690 : /* Update the pg_enum entry */
691 6 : namestrcpy(&en->enumlabel, newVal);
692 6 : CatalogTupleUpdate(pg_enum, &enum_tup->t_self, enum_tup);
693 6 : heap_freetuple(enum_tup);
694 :
695 6 : table_close(pg_enum, RowExclusiveLock);
696 6 : }
697 :
698 :
699 : /*
700 : * Test if the given type OID is in the table of uncommitted enum types.
701 : */
702 : static bool
703 174 : EnumTypeUncommitted(Oid typ_id)
704 : {
705 : bool found;
706 :
707 : /* If we've made no uncommitted types table, it's not in the table */
708 174 : if (uncommitted_enum_types == NULL)
709 118 : return false;
710 :
711 : /* Else, is it in the table? */
712 56 : (void) hash_search(uncommitted_enum_types, &typ_id, HASH_FIND, &found);
713 56 : return found;
714 : }
715 :
716 :
717 : /*
718 : * Test if the given enum value is in the table of uncommitted enum values.
719 : */
720 : bool
721 45 : EnumUncommitted(Oid enum_id)
722 : {
723 : bool found;
724 :
725 : /* If we've made no uncommitted values table, it's not in the table */
726 45 : if (uncommitted_enum_values == NULL)
727 33 : return false;
728 :
729 : /* Else, is it in the table? */
730 12 : (void) hash_search(uncommitted_enum_values, &enum_id, HASH_FIND, &found);
731 12 : return found;
732 : }
733 :
734 :
735 : /*
736 : * Clean up enum stuff after end of top-level transaction.
737 : */
738 : void
739 577677 : AtEOXact_Enum(void)
740 : {
741 : /*
742 : * Reset the uncommitted tables, as all our tuples are now committed. The
743 : * memory will go away automatically when TopTransactionContext is freed;
744 : * it's sufficient to clear our pointers.
745 : */
746 577677 : uncommitted_enum_types = NULL;
747 577677 : uncommitted_enum_values = NULL;
748 577677 : }
749 :
750 :
751 : /*
752 : * RenumberEnumType
753 : * Renumber existing enum elements to have sort positions 1..n.
754 : *
755 : * We avoid doing this unless absolutely necessary; in most installations
756 : * it will never happen. The reason is that updating existing pg_enum
757 : * entries creates hazards for other backends that are concurrently reading
758 : * pg_enum. Although system catalog scans now use MVCC semantics, the
759 : * syscache machinery might read different pg_enum entries under different
760 : * snapshots, so some other backend might get confused about the proper
761 : * ordering if a concurrent renumbering occurs.
762 : *
763 : * We therefore make the following choices:
764 : *
765 : * 1. Any code that is interested in the enumsortorder values MUST read
766 : * all the relevant pg_enum entries with a single MVCC snapshot, or else
767 : * acquire lock on the enum type to prevent concurrent execution of
768 : * AddEnumLabel().
769 : *
770 : * 2. Code that is not examining enumsortorder can use a syscache
771 : * (for example, enum_in and enum_out do so).
772 : */
773 : static void
774 3 : RenumberEnumType(Relation pg_enum, HeapTuple *existing, int nelems)
775 : {
776 : int i;
777 :
778 : /*
779 : * We should only need to increase existing elements' enumsortorders,
780 : * never decrease them. Therefore, work from the end backwards, to avoid
781 : * unwanted uniqueness violations.
782 : */
783 78 : for (i = nelems - 1; i >= 0; i--)
784 : {
785 : HeapTuple newtup;
786 : Form_pg_enum en;
787 : float4 newsortorder;
788 :
789 75 : newtup = heap_copytuple(existing[i]);
790 75 : en = (Form_pg_enum) GETSTRUCT(newtup);
791 :
792 75 : newsortorder = i + 1;
793 75 : if (en->enumsortorder != newsortorder)
794 : {
795 72 : en->enumsortorder = newsortorder;
796 :
797 72 : CatalogTupleUpdate(pg_enum, &newtup->t_self, newtup);
798 : }
799 :
800 75 : heap_freetuple(newtup);
801 : }
802 :
803 : /* Make the updates visible */
804 3 : CommandCounterIncrement();
805 3 : }
806 :
807 :
808 : /* qsort comparison function for tuples by sort order */
809 : static int
810 8831 : sort_order_cmp(const void *p1, const void *p2)
811 : {
812 8831 : HeapTuple v1 = *((const HeapTuple *) p1);
813 8831 : HeapTuple v2 = *((const HeapTuple *) p2);
814 8831 : Form_pg_enum en1 = (Form_pg_enum) GETSTRUCT(v1);
815 8831 : Form_pg_enum en2 = (Form_pg_enum) GETSTRUCT(v2);
816 :
817 8831 : if (en1->enumsortorder < en2->enumsortorder)
818 3737 : return -1;
819 5094 : else if (en1->enumsortorder > en2->enumsortorder)
820 5094 : return 1;
821 : else
822 0 : return 0;
823 : }
824 :
825 : Size
826 498 : EstimateUncommittedEnumsSpace(void)
827 : {
828 498 : size_t entries = 0;
829 :
830 498 : if (uncommitted_enum_types)
831 0 : entries += hash_get_num_entries(uncommitted_enum_types);
832 498 : if (uncommitted_enum_values)
833 0 : entries += hash_get_num_entries(uncommitted_enum_values);
834 :
835 : /* Add two for the terminators. */
836 498 : return sizeof(Oid) * (entries + 2);
837 : }
838 :
839 : void
840 498 : SerializeUncommittedEnums(void *space, Size size)
841 : {
842 498 : Oid *serialized = (Oid *) space;
843 :
844 : /*
845 : * Make sure the hash tables haven't changed in size since the caller
846 : * reserved the space.
847 : */
848 : Assert(size == EstimateUncommittedEnumsSpace());
849 :
850 : /* Write out all the OIDs from the types hash table, if there is one. */
851 498 : if (uncommitted_enum_types)
852 : {
853 : HASH_SEQ_STATUS status;
854 : Oid *value;
855 :
856 0 : hash_seq_init(&status, uncommitted_enum_types);
857 0 : while ((value = (Oid *) hash_seq_search(&status)))
858 0 : *serialized++ = *value;
859 : }
860 :
861 : /* Write out the terminator. */
862 498 : *serialized++ = InvalidOid;
863 :
864 : /* Write out all the OIDs from the values hash table, if there is one. */
865 498 : if (uncommitted_enum_values)
866 : {
867 : HASH_SEQ_STATUS status;
868 : Oid *value;
869 :
870 0 : hash_seq_init(&status, uncommitted_enum_values);
871 0 : while ((value = (Oid *) hash_seq_search(&status)))
872 0 : *serialized++ = *value;
873 : }
874 :
875 : /* Write out the terminator. */
876 498 : *serialized++ = InvalidOid;
877 :
878 : /*
879 : * Make sure the amount of space we actually used matches what was
880 : * estimated.
881 : */
882 : Assert((char *) serialized == ((char *) space) + size);
883 498 : }
884 :
885 : void
886 1493 : RestoreUncommittedEnums(void *space)
887 : {
888 1493 : Oid *serialized = (Oid *) space;
889 :
890 : Assert(!uncommitted_enum_types);
891 : Assert(!uncommitted_enum_values);
892 :
893 : /*
894 : * If either list is empty then don't even bother to create that hash
895 : * table. This is the common case, since most transactions don't create
896 : * or alter enums.
897 : */
898 1493 : if (OidIsValid(*serialized))
899 : {
900 : /* Read all the types into a new hash table. */
901 0 : init_uncommitted_enum_types();
902 : do
903 : {
904 0 : (void) hash_search(uncommitted_enum_types, serialized++,
905 : HASH_ENTER, NULL);
906 0 : } while (OidIsValid(*serialized));
907 : }
908 1493 : serialized++;
909 1493 : if (OidIsValid(*serialized))
910 : {
911 : /* Read all the values into a new hash table. */
912 0 : init_uncommitted_enum_values();
913 : do
914 : {
915 0 : (void) hash_search(uncommitted_enum_values, serialized++,
916 : HASH_ENTER, NULL);
917 0 : } while (OidIsValid(*serialized));
918 : }
919 1493 : }
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