1 /*-------------------------------------------------------------------------
2 *
3 * toasting.c
4 * This file contains routines to support creation of toast tables
5 *
6 *
7 * Portions Copyright (c) 1996-2021, 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
17 #include "access/heapam.h"
18 #include "access/toast_compression.h"
19 #include "access/xact.h"
20 #include "catalog/binary_upgrade.h"
21 #include "catalog/catalog.h"
22 #include "catalog/dependency.h"
23 #include "catalog/heap.h"
24 #include "catalog/index.h"
25 #include "catalog/namespace.h"
26 #include "catalog/pg_am.h"
27 #include "catalog/pg_namespace.h"
28 #include "catalog/pg_opclass.h"
29 #include "catalog/pg_type.h"
30 #include "catalog/toasting.h"
31 #include "miscadmin.h"
32 #include "nodes/makefuncs.h"
33 #include "storage/lock.h"
34 #include "utils/builtins.h"
35 #include "utils/rel.h"
36 #include "utils/syscache.h"
37
38 static void CheckAndCreateToastTable(Oid relOid, Datum reloptions,
39 LOCKMODE lockmode, bool check,
40 Oid OIDOldToast);
41 static bool create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
42 Datum reloptions, LOCKMODE lockmode, bool check,
43 Oid OIDOldToast);
44 static bool needs_toast_table(Relation rel);
45
46
47 /*
48 * CreateToastTable variants
49 * If the table needs a toast table, and doesn't already have one,
50 * then create a toast table for it.
51 *
52 * reloptions for the toast table can be passed, too. Pass (Datum) 0
53 * for default reloptions.
54 *
55 * We expect the caller to have verified that the relation is a table and have
56 * already done any necessary permission checks. Callers expect this function
57 * to end with CommandCounterIncrement if it makes any changes.
58 */
59 void
AlterTableCreateToastTable(Oid relOid,Datum reloptions,LOCKMODE lockmode)60 AlterTableCreateToastTable(Oid relOid, Datum reloptions, LOCKMODE lockmode)
61 {
62 CheckAndCreateToastTable(relOid, reloptions, lockmode, true, InvalidOid);
63 }
64
65 void
NewHeapCreateToastTable(Oid relOid,Datum reloptions,LOCKMODE lockmode,Oid OIDOldToast)66 NewHeapCreateToastTable(Oid relOid, Datum reloptions, LOCKMODE lockmode,
67 Oid OIDOldToast)
68 {
69 CheckAndCreateToastTable(relOid, reloptions, lockmode, false, OIDOldToast);
70 }
71
72 void
NewRelationCreateToastTable(Oid relOid,Datum reloptions)73 NewRelationCreateToastTable(Oid relOid, Datum reloptions)
74 {
75 CheckAndCreateToastTable(relOid, reloptions, AccessExclusiveLock, false,
76 InvalidOid);
77 }
78
79 static void
CheckAndCreateToastTable(Oid relOid,Datum reloptions,LOCKMODE lockmode,bool check,Oid OIDOldToast)80 CheckAndCreateToastTable(Oid relOid, Datum reloptions, LOCKMODE lockmode,
81 bool check, Oid OIDOldToast)
82 {
83 Relation rel;
84
85 rel = table_open(relOid, lockmode);
86
87 /* create_toast_table does all the work */
88 (void) create_toast_table(rel, InvalidOid, InvalidOid, reloptions, lockmode,
89 check, OIDOldToast);
90
91 table_close(rel, NoLock);
92 }
93
94 /*
95 * Create a toast table during bootstrap
96 *
97 * Here we need to prespecify the OIDs of the toast table and its index
98 */
99 void
BootstrapToastTable(char * relName,Oid toastOid,Oid toastIndexOid)100 BootstrapToastTable(char *relName, Oid toastOid, Oid toastIndexOid)
101 {
102 Relation rel;
103
104 rel = table_openrv(makeRangeVar(NULL, relName, -1), AccessExclusiveLock);
105
106 if (rel->rd_rel->relkind != RELKIND_RELATION &&
107 rel->rd_rel->relkind != RELKIND_MATVIEW)
108 ereport(ERROR,
109 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
110 errmsg("\"%s\" is not a table or materialized view",
111 relName)));
112
113 /* create_toast_table does all the work */
114 if (!create_toast_table(rel, toastOid, toastIndexOid, (Datum) 0,
115 AccessExclusiveLock, false, InvalidOid))
116 elog(ERROR, "\"%s\" does not require a toast table",
117 relName);
118
119 table_close(rel, NoLock);
120 }
121
122
123 /*
124 * create_toast_table --- internal workhorse
125 *
126 * rel is already opened and locked
127 * toastOid and toastIndexOid are normally InvalidOid, but during
128 * bootstrap they can be nonzero to specify hand-assigned OIDs
129 */
130 static bool
create_toast_table(Relation rel,Oid toastOid,Oid toastIndexOid,Datum reloptions,LOCKMODE lockmode,bool check,Oid OIDOldToast)131 create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
132 Datum reloptions, LOCKMODE lockmode, bool check,
133 Oid OIDOldToast)
134 {
135 Oid relOid = RelationGetRelid(rel);
136 HeapTuple reltup;
137 TupleDesc tupdesc;
138 bool shared_relation;
139 bool mapped_relation;
140 Relation toast_rel;
141 Relation class_rel;
142 Oid toast_relid;
143 Oid namespaceid;
144 char toast_relname[NAMEDATALEN];
145 char toast_idxname[NAMEDATALEN];
146 IndexInfo *indexInfo;
147 Oid collationObjectId[2];
148 Oid classObjectId[2];
149 int16 coloptions[2];
150 ObjectAddress baseobject,
151 toastobject;
152
153 /*
154 * Is it already toasted?
155 */
156 if (rel->rd_rel->reltoastrelid != InvalidOid)
157 return false;
158
159 /*
160 * Check to see whether the table actually needs a TOAST table.
161 */
162 if (!IsBinaryUpgrade)
163 {
164 /* Normal mode, normal check */
165 if (!needs_toast_table(rel))
166 return false;
167 }
168 else
169 {
170 /*
171 * In binary-upgrade mode, create a TOAST table if and only if
172 * pg_upgrade told us to (ie, a TOAST table OID has been provided).
173 *
174 * This indicates that the old cluster had a TOAST table for the
175 * current table. We must create a TOAST table to receive the old
176 * TOAST file, even if the table seems not to need one.
177 *
178 * Contrariwise, if the old cluster did not have a TOAST table, we
179 * should be able to get along without one even if the new version's
180 * needs_toast_table rules suggest we should have one. There is a lot
181 * of daylight between where we will create a TOAST table and where
182 * one is really necessary to avoid failures, so small cross-version
183 * differences in the when-to-create heuristic shouldn't be a problem.
184 * If we tried to create a TOAST table anyway, we would have the
185 * problem that it might take up an OID that will conflict with some
186 * old-cluster table we haven't seen yet.
187 */
188 if (!OidIsValid(binary_upgrade_next_toast_pg_class_oid))
189 return false;
190 }
191
192 /*
193 * If requested check lockmode is sufficient. This is a cross check in
194 * case of errors or conflicting decisions in earlier code.
195 */
196 if (check && lockmode != AccessExclusiveLock)
197 elog(ERROR, "AccessExclusiveLock required to add toast table.");
198
199 /*
200 * Create the toast table and its index
201 */
202 snprintf(toast_relname, sizeof(toast_relname),
203 "pg_toast_%u", relOid);
204 snprintf(toast_idxname, sizeof(toast_idxname),
205 "pg_toast_%u_index", relOid);
206
207 /* this is pretty painful... need a tuple descriptor */
208 tupdesc = CreateTemplateTupleDesc(3);
209 TupleDescInitEntry(tupdesc, (AttrNumber) 1,
210 "chunk_id",
211 OIDOID,
212 -1, 0);
213 TupleDescInitEntry(tupdesc, (AttrNumber) 2,
214 "chunk_seq",
215 INT4OID,
216 -1, 0);
217 TupleDescInitEntry(tupdesc, (AttrNumber) 3,
218 "chunk_data",
219 BYTEAOID,
220 -1, 0);
221
222 /*
223 * Ensure that the toast table doesn't itself get toasted, or we'll be
224 * toast :-(. This is essential for chunk_data because type bytea is
225 * toastable; hit the other two just to be sure.
226 */
227 TupleDescAttr(tupdesc, 0)->attstorage = TYPSTORAGE_PLAIN;
228 TupleDescAttr(tupdesc, 1)->attstorage = TYPSTORAGE_PLAIN;
229 TupleDescAttr(tupdesc, 2)->attstorage = TYPSTORAGE_PLAIN;
230
231 /* Toast field should not be compressed */
232 TupleDescAttr(tupdesc, 0)->attcompression = InvalidCompressionMethod;
233 TupleDescAttr(tupdesc, 1)->attcompression = InvalidCompressionMethod;
234 TupleDescAttr(tupdesc, 2)->attcompression = InvalidCompressionMethod;
235
236 /*
237 * Toast tables for regular relations go in pg_toast; those for temp
238 * relations go into the per-backend temp-toast-table namespace.
239 */
240 if (isTempOrTempToastNamespace(rel->rd_rel->relnamespace))
241 namespaceid = GetTempToastNamespace();
242 else
243 namespaceid = PG_TOAST_NAMESPACE;
244
245 /* Toast table is shared if and only if its parent is. */
246 shared_relation = rel->rd_rel->relisshared;
247
248 /* It's mapped if and only if its parent is, too */
249 mapped_relation = RelationIsMapped(rel);
250
251 toast_relid = heap_create_with_catalog(toast_relname,
252 namespaceid,
253 rel->rd_rel->reltablespace,
254 toastOid,
255 InvalidOid,
256 InvalidOid,
257 rel->rd_rel->relowner,
258 table_relation_toast_am(rel),
259 tupdesc,
260 NIL,
261 RELKIND_TOASTVALUE,
262 rel->rd_rel->relpersistence,
263 shared_relation,
264 mapped_relation,
265 ONCOMMIT_NOOP,
266 reloptions,
267 false,
268 true,
269 true,
270 OIDOldToast,
271 NULL);
272 Assert(toast_relid != InvalidOid);
273
274 /* make the toast relation visible, else table_open will fail */
275 CommandCounterIncrement();
276
277 /* ShareLock is not really needed here, but take it anyway */
278 toast_rel = table_open(toast_relid, ShareLock);
279
280 /*
281 * Create unique index on chunk_id, chunk_seq.
282 *
283 * NOTE: the normal TOAST access routines could actually function with a
284 * single-column index on chunk_id only. However, the slice access
285 * routines use both columns for faster access to an individual chunk. In
286 * addition, we want it to be unique as a check against the possibility of
287 * duplicate TOAST chunk OIDs. The index might also be a little more
288 * efficient this way, since btree isn't all that happy with large numbers
289 * of equal keys.
290 */
291
292 indexInfo = makeNode(IndexInfo);
293 indexInfo->ii_NumIndexAttrs = 2;
294 indexInfo->ii_NumIndexKeyAttrs = 2;
295 indexInfo->ii_IndexAttrNumbers[0] = 1;
296 indexInfo->ii_IndexAttrNumbers[1] = 2;
297 indexInfo->ii_Expressions = NIL;
298 indexInfo->ii_ExpressionsState = NIL;
299 indexInfo->ii_Predicate = NIL;
300 indexInfo->ii_PredicateState = NULL;
301 indexInfo->ii_ExclusionOps = NULL;
302 indexInfo->ii_ExclusionProcs = NULL;
303 indexInfo->ii_ExclusionStrats = NULL;
304 indexInfo->ii_OpclassOptions = NULL;
305 indexInfo->ii_Unique = true;
306 indexInfo->ii_ReadyForInserts = true;
307 indexInfo->ii_Concurrent = false;
308 indexInfo->ii_BrokenHotChain = false;
309 indexInfo->ii_ParallelWorkers = 0;
310 indexInfo->ii_Am = BTREE_AM_OID;
311 indexInfo->ii_AmCache = NULL;
312 indexInfo->ii_Context = CurrentMemoryContext;
313
314 collationObjectId[0] = InvalidOid;
315 collationObjectId[1] = InvalidOid;
316
317 classObjectId[0] = OID_BTREE_OPS_OID;
318 classObjectId[1] = INT4_BTREE_OPS_OID;
319
320 coloptions[0] = 0;
321 coloptions[1] = 0;
322
323 index_create(toast_rel, toast_idxname, toastIndexOid, InvalidOid,
324 InvalidOid, InvalidOid,
325 indexInfo,
326 list_make2("chunk_id", "chunk_seq"),
327 BTREE_AM_OID,
328 rel->rd_rel->reltablespace,
329 collationObjectId, classObjectId, coloptions, (Datum) 0,
330 INDEX_CREATE_IS_PRIMARY, 0, true, true, NULL);
331
332 table_close(toast_rel, NoLock);
333
334 /*
335 * Store the toast table's OID in the parent relation's pg_class row
336 */
337 class_rel = table_open(RelationRelationId, RowExclusiveLock);
338
339 reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relOid));
340 if (!HeapTupleIsValid(reltup))
341 elog(ERROR, "cache lookup failed for relation %u", relOid);
342
343 ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
344
345 if (!IsBootstrapProcessingMode())
346 {
347 /* normal case, use a transactional update */
348 CatalogTupleUpdate(class_rel, &reltup->t_self, reltup);
349 }
350 else
351 {
352 /* While bootstrapping, we cannot UPDATE, so overwrite in-place */
353 heap_inplace_update(class_rel, reltup);
354 }
355
356 heap_freetuple(reltup);
357
358 table_close(class_rel, RowExclusiveLock);
359
360 /*
361 * Register dependency from the toast table to the main, so that the toast
362 * table will be deleted if the main is. Skip this in bootstrap mode.
363 */
364 if (!IsBootstrapProcessingMode())
365 {
366 baseobject.classId = RelationRelationId;
367 baseobject.objectId = relOid;
368 baseobject.objectSubId = 0;
369 toastobject.classId = RelationRelationId;
370 toastobject.objectId = toast_relid;
371 toastobject.objectSubId = 0;
372
373 recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
374 }
375
376 /*
377 * Make changes visible
378 */
379 CommandCounterIncrement();
380
381 return true;
382 }
383
384 /*
385 * Check to see whether the table needs a TOAST table.
386 */
387 static bool
needs_toast_table(Relation rel)388 needs_toast_table(Relation rel)
389 {
390 /*
391 * No need to create a TOAST table for partitioned tables.
392 */
393 if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
394 return false;
395
396 /*
397 * We cannot allow toasting a shared relation after initdb (because
398 * there's no way to mark it toasted in other databases' pg_class).
399 */
400 if (rel->rd_rel->relisshared && !IsBootstrapProcessingMode())
401 return false;
402
403 /*
404 * Ignore attempts to create toast tables on catalog tables after initdb.
405 * Which catalogs get toast tables is explicitly chosen in catalog/pg_*.h.
406 * (We could get here via some ALTER TABLE command if the catalog doesn't
407 * have a toast table.)
408 */
409 if (IsCatalogRelation(rel) && !IsBootstrapProcessingMode())
410 return false;
411
412 /* Otherwise, let the AM decide. */
413 return table_relation_needs_toast_table(rel);
414 }
415