granicus.if.org Git - postgresql/blob - src/backend/access/transam/xlogutils.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * xlogutils.c
   4  *
   5  *
   6  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  * $Header: /cvsroot/pgsql/src/backend/access/transam/xlogutils.c,v 1.14 2001/03/13 01:17:05 tgl Exp $
  10  *
  11  *-------------------------------------------------------------------------
  12  */
  13 #include "postgres.h"
  14
  15 #include "access/xlog.h"
  16 #include "access/transam.h"
  17 #include "access/xact.h"
  18 #include "storage/bufpage.h"
  19 #include "storage/bufmgr.h"
  20 #include "storage/smgr.h"
  21 #include "access/htup.h"
  22 #include "access/xlogutils.h"
  23 #include "catalog/pg_database.h"
  24 #include "lib/hasht.h"
  25 #include "utils/relcache.h"
  26
  27 /*
  28  * ---------------------------------------------------------------
  29  *
  30  * Index support functions
  31  *
  32  *----------------------------------------------------------------
  33  */
  34
  35 /*
  36  * Check if specified heap tuple was inserted by given
  37  * xaction/command and return
  38  *
  39  * - -1 if not
  40  * - 0  if there is no tuple at all
  41  * - 1  if yes
  42  */
  43 int
  44 XLogIsOwnerOfTuple(RelFileNode hnode, ItemPointer iptr,
  45                                         TransactionId xid, CommandId cid)
  46 {
  47         Relation                reln;
  48         Buffer                  buffer;
  49         Page                    page;
  50         ItemId                  lp;
  51         HeapTupleHeader htup;
  52
  53         reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
  54         if (!RelationIsValid(reln))
  55                 return(0);
  56
  57         buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
  58         if (!BufferIsValid(buffer))
  59                 return(0);
  60
  61         LockBuffer(buffer, BUFFER_LOCK_SHARE);
  62         page = (Page) BufferGetPage(buffer);
  63         if (PageIsNew((PageHeader) page) ||
  64                 ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
  65         {
  66                 UnlockAndReleaseBuffer(buffer);
  67                 return(0);
  68         }
  69         lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
  70         if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
  71         {
  72                 UnlockAndReleaseBuffer(buffer);
  73                 return(0);
  74         }
  75
  76         htup = (HeapTupleHeader) PageGetItem(page, lp);
  77
  78         Assert(PageGetSUI(page) == ThisStartUpID);
  79         if (htup->t_xmin != xid || htup->t_cmin != cid)
  80         {
  81                 UnlockAndReleaseBuffer(buffer);
  82                 return(-1);
  83         }
  84
  85         UnlockAndReleaseBuffer(buffer);
  86         return(1);
  87 }
  88
  89 /*
  90  * MUST BE CALLED ONLY ON RECOVERY.
  91  *
  92  * Check if exists valid (inserted by not aborted xaction) heap tuple
  93  * for given item pointer
  94  */
  95 bool
  96 XLogIsValidTuple(RelFileNode hnode, ItemPointer iptr)
  97 {
  98         Relation                reln;
  99         Buffer                  buffer;
 100         Page                    page;
 101         ItemId                  lp;
 102         HeapTupleHeader htup;
 103
 104         reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
 105         if (!RelationIsValid(reln))
 106                 return(false);
 107
 108         buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
 109         if (!BufferIsValid(buffer))
 110                 return(false);
 111
 112         LockBuffer(buffer, BUFFER_LOCK_SHARE);
 113         page = (Page) BufferGetPage(buffer);
 114         if (PageIsNew((PageHeader) page) ||
 115                 ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
 116         {
 117                 UnlockAndReleaseBuffer(buffer);
 118                 return(false);
 119         }
 120
 121         if (PageGetSUI(page) != ThisStartUpID)
 122         {
 123                 Assert(PageGetSUI(page) < ThisStartUpID);
 124                 UnlockAndReleaseBuffer(buffer);
 125                 return(true);
 126         }
 127
 128         lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
 129         if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
 130         {
 131                 UnlockAndReleaseBuffer(buffer);
 132                 return(false);
 133         }
 134
 135         htup = (HeapTupleHeader) PageGetItem(page, lp);
 136
 137         /* MUST CHECK WASN'T TUPLE INSERTED IN PREV STARTUP */
 138
 139         if (!(htup->t_infomask & HEAP_XMIN_COMMITTED))
 140         {
 141                 if (htup->t_infomask & HEAP_XMIN_INVALID ||
 142                         (htup->t_infomask & HEAP_MOVED_IN &&
 143                         TransactionIdDidAbort((TransactionId)htup->t_cmin)) ||
 144                         TransactionIdDidAbort(htup->t_xmin))
 145                 {
 146                         UnlockAndReleaseBuffer(buffer);
 147                         return(false);
 148                 }
 149         }
 150
 151         UnlockAndReleaseBuffer(buffer);
 152         return(true);
 153 }
 154
 155 /*
 156  * Open pg_log in recovery
 157  */
 158 extern Relation LogRelation;    /* pg_log relation */
 159
 160 void
 161 XLogOpenLogRelation(void)
 162 {
 163         Relation        logRelation;
 164
 165         Assert(!LogRelation);
 166         logRelation = (Relation) malloc(sizeof(RelationData));
 167         memset(logRelation, 0, sizeof(RelationData));
 168         logRelation->rd_rel = (Form_pg_class) malloc(sizeof(FormData_pg_class));
 169         memset(logRelation->rd_rel, 0, sizeof(FormData_pg_class));
 170
 171         sprintf(RelationGetPhysicalRelationName(logRelation), "pg_log");
 172         logRelation->rd_node.tblNode = InvalidOid;
 173         logRelation->rd_node.relNode = RelOid_pg_log;
 174         logRelation->rd_fd = -1;
 175         logRelation->rd_fd = smgropen(DEFAULT_SMGR, logRelation, false);
 176         if (logRelation->rd_fd < 0)
 177                 elog(STOP, "XLogOpenLogRelation: failed to open pg_log");
 178         LogRelation = logRelation;
 179 }
 180
 181 /*
 182  * ---------------------------------------------------------------
 183  *
 184  * Storage related support functions
 185  *
 186  *----------------------------------------------------------------
 187  */
 188
 189 Buffer
 190 XLogReadBuffer(bool extend, Relation reln, BlockNumber blkno)
 191 {
 192         BlockNumber     lastblock = RelationGetNumberOfBlocks(reln);
 193         Buffer          buffer;
 194
 195         if (blkno >= lastblock)
 196         {
 197                 buffer = InvalidBuffer;
 198                 if (extend)             /* we do this in recovery only - no locks */
 199                 {
 200                         Assert(InRecovery);
 201                         while (lastblock <= blkno)
 202                         {
 203                                 if (buffer != InvalidBuffer)
 204                                         ReleaseBuffer(buffer); /* must be WriteBuffer()? */
 205                                 buffer = ReadBuffer(reln, P_NEW);
 206                                 lastblock++;
 207                         }
 208                 }
 209                 if (buffer != InvalidBuffer)
 210                         LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 211                 return(buffer);
 212         }
 213
 214         buffer = ReadBuffer(reln, blkno);
 215         if (buffer != InvalidBuffer)
 216                 LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 217         return(buffer);
 218 }
 219
 220 /*
 221  * "Relation" cache
 222  */
 223
 224 typedef struct XLogRelDesc
 225 {
 226         RelationData                    reldata;
 227         struct XLogRelDesc         *lessRecently;
 228         struct XLogRelDesc         *moreRecently;
 229 } XLogRelDesc;
 230
 231 typedef struct XLogRelCacheEntry
 232 {
 233         RelFileNode             rnode;
 234         XLogRelDesc        *rdesc;
 235 } XLogRelCacheEntry;
 236
 237 static HTAB                                *_xlrelcache;
 238 static XLogRelDesc                 *_xlrelarr = NULL;
 239 static Form_pg_class            _xlpgcarr = NULL;
 240 static int                                      _xlast = 0;
 241 static int                                      _xlcnt = 0;
 242 #define _XLOG_RELCACHESIZE      512
 243
 244 static void
 245 _xl_init_rel_cache(void)
 246 {
 247         HASHCTL                 ctl;
 248
 249         _xlcnt = _XLOG_RELCACHESIZE;
 250         _xlast = 0;
 251         _xlrelarr = (XLogRelDesc*) malloc(sizeof(XLogRelDesc) * _xlcnt);
 252         memset(_xlrelarr, 0, sizeof(XLogRelDesc) * _xlcnt);
 253         _xlpgcarr = (Form_pg_class) malloc(sizeof(FormData_pg_class) * _xlcnt);
 254         memset(_xlpgcarr, 0, sizeof(FormData_pg_class) * _xlcnt);
 255
 256         _xlrelarr[0].moreRecently = &(_xlrelarr[0]);
 257         _xlrelarr[0].lessRecently = &(_xlrelarr[0]);
 258
 259         memset(&ctl, 0, (int) sizeof(ctl));
 260         ctl.keysize = sizeof(RelFileNode);
 261         ctl.datasize = sizeof(XLogRelDesc*);
 262         ctl.hash = tag_hash;
 263
 264         _xlrelcache = hash_create(_XLOG_RELCACHESIZE, &ctl,
 265                                                                 HASH_ELEM | HASH_FUNCTION);
 266 }
 267
 268 static void
 269 _xl_remove_hash_entry(XLogRelDesc **edata, Datum dummy)
 270 {
 271         XLogRelCacheEntry          *hentry;
 272         bool                                    found;
 273         XLogRelDesc                        *rdesc = *edata;
 274         Form_pg_class                   tpgc = rdesc->reldata.rd_rel;
 275
 276         rdesc->lessRecently->moreRecently = rdesc->moreRecently;
 277         rdesc->moreRecently->lessRecently = rdesc->lessRecently;
 278
 279         hentry = (XLogRelCacheEntry*) hash_search(_xlrelcache,
 280                 (char*)&(rdesc->reldata.rd_node), HASH_REMOVE, &found);
 281
 282         if (hentry == NULL)
 283                 elog(STOP, "_xl_remove_hash_entry: can't delete from cache");
 284         if (!found)
 285                 elog(STOP, "_xl_remove_hash_entry: file was not found in cache");
 286
 287         if (rdesc->reldata.rd_fd >= 0)
 288                 smgrclose(DEFAULT_SMGR, &(rdesc->reldata));
 289
 290         memset(rdesc, 0, sizeof(XLogRelDesc));
 291         memset(tpgc, 0, sizeof(FormData_pg_class));
 292         rdesc->reldata.rd_rel = tpgc;
 293
 294         return;
 295 }
 296
 297 static XLogRelDesc*
 298 _xl_new_reldesc(void)
 299 {
 300         XLogRelDesc        *res;
 301
 302         _xlast++;
 303         if (_xlast < _xlcnt)
 304         {
 305                 _xlrelarr[_xlast].reldata.rd_rel = &(_xlpgcarr[_xlast]);
 306                 return(&(_xlrelarr[_xlast]));
 307         }
 308
 309         /* reuse */
 310         res = _xlrelarr[0].moreRecently;
 311
 312         _xl_remove_hash_entry(&res, 0);
 313
 314         _xlast--;
 315         return(res);
 316 }
 317
 318
 319 void
 320 XLogInitRelationCache(void)
 321 {
 322         CreateDummyCaches();
 323         _xl_init_rel_cache();
 324 }
 325
 326 void
 327 XLogCloseRelationCache(void)
 328 {
 329
 330         DestroyDummyCaches();
 331
 332         if (!_xlrelarr)
 333                 return;
 334
 335         HashTableWalk(_xlrelcache, (HashtFunc) _xl_remove_hash_entry, 0);
 336         hash_destroy(_xlrelcache);
 337
 338         free(_xlrelarr);
 339         free(_xlpgcarr);
 340
 341         _xlrelarr = NULL;
 342 }
 343
 344 Relation
 345 XLogOpenRelation(bool redo, RmgrId rmid, RelFileNode rnode)
 346 {
 347         XLogRelDesc                        *res;
 348         XLogRelCacheEntry          *hentry;
 349         bool                                    found;
 350
 351         hentry = (XLogRelCacheEntry*)
 352                         hash_search(_xlrelcache, (char*)&rnode, HASH_FIND, &found);
 353
 354         if (hentry == NULL)
 355                 elog(STOP, "XLogOpenRelation: error in cache");
 356
 357         if (found)
 358         {
 359                 res = hentry->rdesc;
 360
 361                 res->lessRecently->moreRecently = res->moreRecently;
 362                 res->moreRecently->lessRecently = res->lessRecently;
 363         }
 364         else
 365         {
 366                 res = _xl_new_reldesc();
 367
 368                 sprintf(RelationGetPhysicalRelationName(&(res->reldata)), "%u", rnode.relNode);
 369
 370                 /* unexisting DB id */
 371                 res->reldata.rd_lockInfo.lockRelId.dbId = RecoveryDb;
 372                 res->reldata.rd_lockInfo.lockRelId.relId = rnode.relNode;
 373                 res->reldata.rd_node = rnode;
 374
 375                 hentry = (XLogRelCacheEntry*)
 376                         hash_search(_xlrelcache, (char*)&rnode, HASH_ENTER, &found);
 377
 378                 if (hentry == NULL)
 379                         elog(STOP, "XLogOpenRelation: can't insert into cache");
 380
 381                 if (found)
 382                         elog(STOP, "XLogOpenRelation: file found on insert into cache");
 383
 384                 hentry->rdesc = res;
 385
 386                 res->reldata.rd_fd = -1;
 387                 res->reldata.rd_fd = smgropen(DEFAULT_SMGR, &(res->reldata),
 388                                                                           true /* allow failure */);
 389         }
 390
 391         res->moreRecently = &(_xlrelarr[0]);
 392         res->lessRecently = _xlrelarr[0].lessRecently;
 393         _xlrelarr[0].lessRecently = res;
 394         res->lessRecently->moreRecently = res;
 395
 396         if (res->reldata.rd_fd < 0)             /* file doesn't exist */
 397                 return(NULL);
 398
 399         return(&(res->reldata));
 400 }