1 /*-------------------------------------------------------------------------
2 *
3 * toasting.c
4 * This file contains routines to support creation of toast tables
5 *
6 *
7 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
9 *
10 * IDENTIFICATION
11 * src/backend/catalog/toasting.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
new() -> Self17 #include "access/heapam.h"
18 #include "access/xact.h"
19 #include "catalog/binary_upgrade.h"
20 #include "catalog/catalog.h"
21 #include "catalog/dependency.h"
22 #include "catalog/heap.h"
23 #include "catalog/index.h"
24 #include "catalog/namespace.h"
25 #include "catalog/pg_am.h"
26 #include "catalog/pg_namespace.h"
27 #include "catalog/pg_opclass.h"
28 #include "catalog/pg_type.h"
29 #include "catalog/toasting.h"
30 #include "miscadmin.h"
31 #include "nodes/makefuncs.h"
32 #include "storage/lock.h"
33 #include "utils/builtins.h"
34 #include "utils/rel.h"
35 #include "utils/syscache.h"
36
37 /* Potentially set by pg_upgrade_support functions */
38 Oid binary_upgrade_next_toast_pg_type_oid = InvalidOid;
39
40 static void CheckAndCreateToastTable(Oid relOid, Datum reloptions,
41 LOCKMODE lockmode, bool check,
42 Oid OIDOldToast);
43 static bool create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
44 Datum reloptions, LOCKMODE lockmode, bool check,
45 Oid OIDOldToast);
46 static bool needs_toast_table(Relation rel);
47
48
49 /*
50 * CreateToastTable variants
51 * If the table needs a toast table, and doesn't already have one,
52 * then create a toast table for it.
53 *
54 * reloptions for the toast table can be passed, too. Pass (Datum) 0
55 * for default reloptions.
56 *
57 * We expect the caller to have verified that the relation is a table and have
58 * already done any necessary permission checks. Callers expect this function
59 * to end with CommandCounterIncrement if it makes any changes.
60 */
61 void
62 AlterTableCreateToastTable(Oid relOid, Datum reloptions, LOCKMODE lockmode)
63 {
64 CheckAndCreateToastTable(relOid, reloptions, lockmode, true, InvalidOid);
65 }
66
67 void
68 NewHeapCreateToastTable(Oid relOid, Datum reloptions, LOCKMODE lockmode,
69 Oid OIDOldToast)
70 {
71 CheckAndCreateToastTable(relOid, reloptions, lockmode, false, OIDOldToast);
72 }
73
74 void
75 NewRelationCreateToastTable(Oid relOid, Datum reloptions)
76 {
77 CheckAndCreateToastTable(relOid, reloptions, AccessExclusiveLock, false,
78 InvalidOid);
79 }
80
81 static void
82 CheckAndCreateToastTable(Oid relOid, Datum reloptions, LOCKMODE lockmode,
83 bool check, Oid OIDOldToast)
84 {
85 Relation rel;
86
87 rel = table_open(relOid, lockmode);
88
89 /* create_toast_table does all the work */
90 (void) create_toast_table(rel, InvalidOid, InvalidOid, reloptions, lockmode,
91 check, OIDOldToast);
92
93 table_close(rel, NoLock);
94 }
95
96 /*
97 * Create a toast table during bootstrap
98 *
99 * Here we need to prespecify the OIDs of the toast table and its index
100 */
101 void
102 BootstrapToastTable(char *relName, Oid toastOid, Oid toastIndexOid)
103 {
104 Relation rel;
105
106 rel = table_openrv(makeRangeVar(NULL, relName, -1), AccessExclusiveLock);
107
108 if (rel->rd_rel->relkind != RELKIND_RELATION &&
109 rel->rd_rel->relkind != RELKIND_MATVIEW)
110 ereport(ERROR,
111 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
112 errmsg("\"%s\" is not a table or materialized view",
113 relName)));
114
115 /* create_toast_table does all the work */
116 if (!create_toast_table(rel, toastOid, toastIndexOid, (Datum) 0,
117 AccessExclusiveLock, false, InvalidOid))
118 elog(ERROR, "\"%s\" does not require a toast table",
119 relName);
120
121 table_close(rel, NoLock);
122 }
123
124
125 /*
126 * create_toast_table --- internal workhorse
127 *
128 * rel is already opened and locked
129 * toastOid and toastIndexOid are normally InvalidOid, but during
130 * bootstrap they can be nonzero to specify hand-assigned OIDs
131 */
132 static bool
133 create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
134 Datum reloptions, LOCKMODE lockmode, bool check,
135 Oid OIDOldToast)
136 {
137 Oid relOid = RelationGetRelid(rel);
138 HeapTuple reltup;
139 TupleDesc tupdesc;
140 bool shared_relation;
141 bool mapped_relation;
142 Relation toast_rel;
143 Relation class_rel;
144 Oid toast_relid;
145 Oid toast_typid = InvalidOid;
146 Oid namespaceid;
147 char toast_relname[NAMEDATALEN];
148 char toast_idxname[NAMEDATALEN];
149 IndexInfo *indexInfo;
150 Oid collationObjectId[2];
151 Oid classObjectId[2];
152 int16 coloptions[2];
153 ObjectAddress baseobject,
154 toastobject;
155
156 /*
157 * Is it already toasted?
158 */
159 if (rel->rd_rel->reltoastrelid != InvalidOid)
160 return false;
161
162 /*
163 * Check to see whether the table actually needs a TOAST table.
164 */
165 if (!IsBinaryUpgrade)
166 {
167 /* Normal mode, normal check */
168 if (!needs_toast_table(rel))
169 return false;
170 }
171 else
172 {
173 /*
174 * In binary-upgrade mode, create a TOAST table if and only if
175 * pg_upgrade told us to (ie, a TOAST table OID has been provided).
176 *
177 * This indicates that the old cluster had a TOAST table for the
178 * current table. We must create a TOAST table to receive the old
179 * TOAST file, even if the table seems not to need one.
180 *
181 * Contrariwise, if the old cluster did not have a TOAST table, we
182 * should be able to get along without one even if the new version's
183 * needs_toast_table rules suggest we should have one. There is a lot
184 * of daylight between where we will create a TOAST table and where
185 * one is really necessary to avoid failures, so small cross-version
186 * differences in the when-to-create heuristic shouldn't be a problem.
187 * If we tried to create a TOAST table anyway, we would have the
188 * problem that it might take up an OID that will conflict with some
189 * old-cluster table we haven't seen yet.
190 */
191 if (!OidIsValid(binary_upgrade_next_toast_pg_class_oid) ||
192 !OidIsValid(binary_upgrade_next_toast_pg_type_oid))
193 return false;
194 }
195
196 /*
197 * If requested check lockmode is sufficient. This is a cross check in
198 * case of errors or conflicting decisions in earlier code.
199 */
200 if (check && lockmode != AccessExclusiveLock)
201 elog(ERROR, "AccessExclusiveLock required to add toast table.");
202
203 /*
204 * Create the toast table and its index
205 */
206 snprintf(toast_relname, sizeof(toast_relname),
207 "pg_toast_%u", relOid);
208 snprintf(toast_idxname, sizeof(toast_idxname),
209 "pg_toast_%u_index", relOid);
210
211 /* this is pretty painful... need a tuple descriptor */
212 tupdesc = CreateTemplateTupleDesc(3);
213 TupleDescInitEntry(tupdesc, (AttrNumber) 1,
214 "chunk_id",
215 OIDOID,
216 -1, 0);
217 TupleDescInitEntry(tupdesc, (AttrNumber) 2,
218 "chunk_seq",
219 INT4OID,
220 -1, 0);
221 TupleDescInitEntry(tupdesc, (AttrNumber) 3,
222 "chunk_data",
223 BYTEAOID,
224 -1, 0);
225
226 /*
227 * Ensure that the toast table doesn't itself get toasted, or we'll be
228 * toast :-(. This is essential for chunk_data because type bytea is
229 * toastable; hit the other two just to be sure.
230 */
231 TupleDescAttr(tupdesc, 0)->attstorage = 'p';
232 TupleDescAttr(tupdesc, 1)->attstorage = 'p';
233 TupleDescAttr(tupdesc, 2)->attstorage = 'p';
234
235 /*
236 * Toast tables for regular relations go in pg_toast; those for temp
237 * relations go into the per-backend temp-toast-table namespace.
238 */
239 if (isTempOrTempToastNamespace(rel->rd_rel->relnamespace))
240 namespaceid = GetTempToastNamespace();
241 else
242 namespaceid = PG_TOAST_NAMESPACE;
243
244 /*
245 * Use binary-upgrade override for pg_type.oid, if supplied. We might be
246 * in the post-schema-restore phase where we are doing ALTER TABLE to
247 * create TOAST tables that didn't exist in the old cluster.
248 */
249 if (IsBinaryUpgrade && OidIsValid(binary_upgrade_next_toast_pg_type_oid))
250 {
251 toast_typid = binary_upgrade_next_toast_pg_type_oid;
252 binary_upgrade_next_toast_pg_type_oid = InvalidOid;
253 }
254
255 /* Toast table is shared if and only if its parent is. */
256 shared_relation = rel->rd_rel->relisshared;
257
258 /* It's mapped if and only if its parent is, too */
259 mapped_relation = RelationIsMapped(rel);
260
261 toast_relid = heap_create_with_catalog(toast_relname,
262 namespaceid,
263 rel->rd_rel->reltablespace,
264 toastOid,
265 toast_typid,
266 InvalidOid,
267 rel->rd_rel->relowner,
268 rel->rd_rel->relam,
269 tupdesc,
270 NIL,
271 RELKIND_TOASTVALUE,
272 rel->rd_rel->relpersistence,
273 shared_relation,
274 mapped_relation,
275 ONCOMMIT_NOOP,
276 reloptions,
277 false,
278 true,
279 true,
280 OIDOldToast,
281 NULL);
282 Assert(toast_relid != InvalidOid);
283
284 /* make the toast relation visible, else table_open will fail */
285 CommandCounterIncrement();
286
287 /* ShareLock is not really needed here, but take it anyway */
288 toast_rel = table_open(toast_relid, ShareLock);
289
290 /*
291 * Create unique index on chunk_id, chunk_seq.
292 *
293 * NOTE: the normal TOAST access routines could actually function with a
294 * single-column index on chunk_id only. However, the slice access
295 * routines use both columns for faster access to an individual chunk. In
296 * addition, we want it to be unique as a check against the possibility of
297 * duplicate TOAST chunk OIDs. The index might also be a little more
298 * efficient this way, since btree isn't all that happy with large numbers
299 * of equal keys.
300 */
301
302 indexInfo = makeNode(IndexInfo);
303 indexInfo->ii_NumIndexAttrs = 2;
304 indexInfo->ii_NumIndexKeyAttrs = 2;
305 indexInfo->ii_IndexAttrNumbers[0] = 1;
306 indexInfo->ii_IndexAttrNumbers[1] = 2;
307 indexInfo->ii_Expressions = NIL;
308 indexInfo->ii_ExpressionsState = NIL;
309 indexInfo->ii_Predicate = NIL;
310 indexInfo->ii_PredicateState = NULL;
311 indexInfo->ii_ExclusionOps = NULL;
312 indexInfo->ii_ExclusionProcs = NULL;
313 indexInfo->ii_ExclusionStrats = NULL;
314 indexInfo->ii_Unique = true;
315 indexInfo->ii_ReadyForInserts = true;
316 indexInfo->ii_Concurrent = false;
317 indexInfo->ii_BrokenHotChain = false;
318 indexInfo->ii_ParallelWorkers = 0;
319 indexInfo->ii_Am = BTREE_AM_OID;
320 indexInfo->ii_AmCache = NULL;
321 indexInfo->ii_Context = CurrentMemoryContext;
322
323 collationObjectId[0] = InvalidOid;
324 collationObjectId[1] = InvalidOid;
325
326 classObjectId[0] = OID_BTREE_OPS_OID;
327 classObjectId[1] = INT4_BTREE_OPS_OID;
328
329 coloptions[0] = 0;
330 coloptions[1] = 0;
331
332 index_create(toast_rel, toast_idxname, toastIndexOid, InvalidOid,
333 InvalidOid, InvalidOid,
334 indexInfo,
335 list_make2("chunk_id", "chunk_seq"),
336 BTREE_AM_OID,
337 rel->rd_rel->reltablespace,
338 collationObjectId, classObjectId, coloptions, (Datum) 0,
339 INDEX_CREATE_IS_PRIMARY, 0, true, true, NULL);
340
341 table_close(toast_rel, NoLock);
342
343 /*
344 * Store the toast table's OID in the parent relation's pg_class row
345 */
346 class_rel = table_open(RelationRelationId, RowExclusiveLock);
347
348 reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relOid));
349 if (!HeapTupleIsValid(reltup))
350 elog(ERROR, "cache lookup failed for relation %u", relOid);
351
352 ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
353
354 if (!IsBootstrapProcessingMode())
355 {
356 /* normal case, use a transactional update */
357 CatalogTupleUpdate(class_rel, &reltup->t_self, reltup);
358 }
359 else
360 {
361 /* While bootstrapping, we cannot UPDATE, so overwrite in-place */
362 heap_inplace_update(class_rel, reltup);
363 }
364
365 heap_freetuple(reltup);
366
367 table_close(class_rel, RowExclusiveLock);
368
369 /*
370 * Register dependency from the toast table to the master, so that the
371 * toast table will be deleted if the master is. Skip this in bootstrap
372 * mode.
373 */
374 if (!IsBootstrapProcessingMode())
375 {
376 baseobject.classId = RelationRelationId;
377 baseobject.objectId = relOid;
378 baseobject.objectSubId = 0;
379 toastobject.classId = RelationRelationId;
380 toastobject.objectId = toast_relid;
381 toastobject.objectSubId = 0;
382
383 recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
384 }
385
386 /*
387 * Make changes visible
388 */
389 CommandCounterIncrement();
390
391 return true;
392 }
393
394 /*
395 * Check to see whether the table needs a TOAST table.
396 */
397 static bool
398 needs_toast_table(Relation rel)
399 {
400 /*
401 * No need to create a TOAST table for partitioned tables.
402 */
403 if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
404 return false;
405
406 /*
407 * We cannot allow toasting a shared relation after initdb (because
408 * there's no way to mark it toasted in other databases' pg_class).
409 */
410 if (rel->rd_rel->relisshared && !IsBootstrapProcessingMode())
411 return false;
412
413 /*
414 * Ignore attempts to create toast tables on catalog tables after initdb.
415 * Which catalogs get toast tables is explicitly chosen in
416 * catalog/toasting.h. (We could get here via some ALTER TABLE command if
417 * the catalog doesn't have a toast table.)
418 */
419 if (IsCatalogRelation(rel) && !IsBootstrapProcessingMode())
420 return false;
421
422 /* Otherwise, let the AM decide. */
423 return table_relation_needs_toast_table(rel);
424 }
425