LCOV - code coverage report
Current view: top level - src/backend/storage/buffer - localbuf.c (source / functions) Hit Total Coverage
Test: PostgreSQL 13devel Lines: 137 168 81.5 %
Date: 2019-11-15 22:06:47 Functions: 10 10 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * localbuf.c
       4             :  *    local buffer manager. Fast buffer manager for temporary tables,
       5             :  *    which never need to be WAL-logged or checkpointed, etc.
       6             :  *
       7             :  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
       8             :  * Portions Copyright (c) 1994-5, Regents of the University of California
       9             :  *
      10             :  *
      11             :  * IDENTIFICATION
      12             :  *    src/backend/storage/buffer/localbuf.c
      13             :  *
      14             :  *-------------------------------------------------------------------------
      15             :  */
      16             : #include "postgres.h"
      17             : 
      18             : #include "access/parallel.h"
      19             : #include "catalog/catalog.h"
      20             : #include "executor/instrument.h"
      21             : #include "storage/buf_internals.h"
      22             : #include "storage/bufmgr.h"
      23             : #include "utils/guc.h"
      24             : #include "utils/memutils.h"
      25             : #include "utils/resowner_private.h"
      26             : 
      27             : 
      28             : /*#define LBDEBUG*/
      29             : 
      30             : /* entry for buffer lookup hashtable */
      31             : typedef struct
      32             : {
      33             :     BufferTag   key;            /* Tag of a disk page */
      34             :     int         id;             /* Associated local buffer's index */
      35             : } LocalBufferLookupEnt;
      36             : 
      37             : /* Note: this macro only works on local buffers, not shared ones! */
      38             : #define LocalBufHdrGetBlock(bufHdr) \
      39             :     LocalBufferBlockPointers[-((bufHdr)->buf_id + 2)]
      40             : 
      41             : int         NLocBuffer = 0;     /* until buffers are initialized */
      42             : 
      43             : BufferDesc *LocalBufferDescriptors = NULL;
      44             : Block      *LocalBufferBlockPointers = NULL;
      45             : int32      *LocalRefCount = NULL;
      46             : 
      47             : static int  nextFreeLocalBuf = 0;
      48             : 
      49             : static HTAB *LocalBufHash = NULL;
      50             : 
      51             : 
      52             : static void InitLocalBuffers(void);
      53             : static Block GetLocalBufferStorage(void);
      54             : 
      55             : 
      56             : /*
      57             :  * LocalPrefetchBuffer -
      58             :  *    initiate asynchronous read of a block of a relation
      59             :  *
      60             :  * Do PrefetchBuffer's work for temporary relations.
      61             :  * No-op if prefetching isn't compiled in.
      62             :  */
      63             : void
      64         212 : LocalPrefetchBuffer(SMgrRelation smgr, ForkNumber forkNum,
      65             :                     BlockNumber blockNum)
      66             : {
      67             : #ifdef USE_PREFETCH
      68             :     BufferTag   newTag;         /* identity of requested block */
      69             :     LocalBufferLookupEnt *hresult;
      70             : 
      71         212 :     INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
      72             : 
      73             :     /* Initialize local buffers if first request in this session */
      74         212 :     if (LocalBufHash == NULL)
      75           0 :         InitLocalBuffers();
      76             : 
      77             :     /* See if the desired buffer already exists */
      78         212 :     hresult = (LocalBufferLookupEnt *)
      79         212 :         hash_search(LocalBufHash, (void *) &newTag, HASH_FIND, NULL);
      80             : 
      81         212 :     if (hresult)
      82             :     {
      83             :         /* Yes, so nothing to do */
      84         212 :         return;
      85             :     }
      86             : 
      87             :     /* Not in buffers, so initiate prefetch */
      88           0 :     smgrprefetch(smgr, forkNum, blockNum);
      89             : #endif                          /* USE_PREFETCH */
      90             : }
      91             : 
      92             : 
      93             : /*
      94             :  * LocalBufferAlloc -
      95             :  *    Find or create a local buffer for the given page of the given relation.
      96             :  *
      97             :  * API is similar to bufmgr.c's BufferAlloc, except that we do not need
      98             :  * to do any locking since this is all local.   Also, IO_IN_PROGRESS
      99             :  * does not get set.  Lastly, we support only default access strategy
     100             :  * (hence, usage_count is always advanced).
     101             :  */
     102             : BufferDesc *
     103      356872 : LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
     104             :                  bool *foundPtr)
     105             : {
     106             :     BufferTag   newTag;         /* identity of requested block */
     107             :     LocalBufferLookupEnt *hresult;
     108             :     BufferDesc *bufHdr;
     109             :     int         b;
     110             :     int         trycounter;
     111             :     bool        found;
     112             :     uint32      buf_state;
     113             : 
     114      356872 :     INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
     115             : 
     116             :     /* Initialize local buffers if first request in this session */
     117      356872 :     if (LocalBufHash == NULL)
     118         566 :         InitLocalBuffers();
     119             : 
     120             :     /* See if the desired buffer already exists */
     121      356872 :     hresult = (LocalBufferLookupEnt *)
     122      356872 :         hash_search(LocalBufHash, (void *) &newTag, HASH_FIND, NULL);
     123             : 
     124      356872 :     if (hresult)
     125             :     {
     126      330586 :         b = hresult->id;
     127      330586 :         bufHdr = GetLocalBufferDescriptor(b);
     128             :         Assert(BUFFERTAGS_EQUAL(bufHdr->tag, newTag));
     129             : #ifdef LBDEBUG
     130             :         fprintf(stderr, "LB ALLOC (%u,%d,%d) %d\n",
     131             :                 smgr->smgr_rnode.node.relNode, forkNum, blockNum, -b - 1);
     132             : #endif
     133      330586 :         buf_state = pg_atomic_read_u32(&bufHdr->state);
     134             : 
     135             :         /* this part is equivalent to PinBuffer for a shared buffer */
     136      330586 :         if (LocalRefCount[b] == 0)
     137             :         {
     138      326668 :             if (BUF_STATE_GET_USAGECOUNT(buf_state) < BM_MAX_USAGE_COUNT)
     139             :             {
     140       44166 :                 buf_state += BUF_USAGECOUNT_ONE;
     141       44166 :                 pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     142             :             }
     143             :         }
     144      330586 :         LocalRefCount[b]++;
     145      330586 :         ResourceOwnerRememberBuffer(CurrentResourceOwner,
     146      330586 :                                     BufferDescriptorGetBuffer(bufHdr));
     147      330586 :         if (buf_state & BM_VALID)
     148      330586 :             *foundPtr = true;
     149             :         else
     150             :         {
     151             :             /* Previous read attempt must have failed; try again */
     152           0 :             *foundPtr = false;
     153             :         }
     154      330586 :         return bufHdr;
     155             :     }
     156             : 
     157             : #ifdef LBDEBUG
     158             :     fprintf(stderr, "LB ALLOC (%u,%d,%d) %d\n",
     159             :             smgr->smgr_rnode.node.relNode, forkNum, blockNum,
     160             :             -nextFreeLocalBuf - 1);
     161             : #endif
     162             : 
     163             :     /*
     164             :      * Need to get a new buffer.  We use a clock sweep algorithm (essentially
     165             :      * the same as what freelist.c does now...)
     166             :      */
     167       26286 :     trycounter = NLocBuffer;
     168             :     for (;;)
     169             :     {
     170       26286 :         b = nextFreeLocalBuf;
     171             : 
     172       26286 :         if (++nextFreeLocalBuf >= NLocBuffer)
     173           0 :             nextFreeLocalBuf = 0;
     174             : 
     175       26286 :         bufHdr = GetLocalBufferDescriptor(b);
     176             : 
     177       26286 :         if (LocalRefCount[b] == 0)
     178             :         {
     179       26286 :             buf_state = pg_atomic_read_u32(&bufHdr->state);
     180             : 
     181       26286 :             if (BUF_STATE_GET_USAGECOUNT(buf_state) > 0)
     182             :             {
     183           0 :                 buf_state -= BUF_USAGECOUNT_ONE;
     184           0 :                 pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     185           0 :                 trycounter = NLocBuffer;
     186             :             }
     187             :             else
     188             :             {
     189             :                 /* Found a usable buffer */
     190       26286 :                 LocalRefCount[b]++;
     191       26286 :                 ResourceOwnerRememberBuffer(CurrentResourceOwner,
     192       26286 :                                             BufferDescriptorGetBuffer(bufHdr));
     193       26286 :                 break;
     194             :             }
     195             :         }
     196           0 :         else if (--trycounter == 0)
     197           0 :             ereport(ERROR,
     198             :                     (errcode(ERRCODE_INSUFFICIENT_RESOURCES),
     199             :                      errmsg("no empty local buffer available")));
     200             :     }
     201             : 
     202             :     /*
     203             :      * this buffer is not referenced but it might still be dirty. if that's
     204             :      * the case, write it out before reusing it!
     205             :      */
     206       26286 :     if (buf_state & BM_DIRTY)
     207             :     {
     208             :         SMgrRelation oreln;
     209           0 :         Page        localpage = (char *) LocalBufHdrGetBlock(bufHdr);
     210             : 
     211             :         /* Find smgr relation for buffer */
     212           0 :         oreln = smgropen(bufHdr->tag.rnode, MyBackendId);
     213             : 
     214           0 :         PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
     215             : 
     216             :         /* And write... */
     217           0 :         smgrwrite(oreln,
     218             :                   bufHdr->tag.forkNum,
     219             :                   bufHdr->tag.blockNum,
     220             :                   localpage,
     221             :                   false);
     222             : 
     223             :         /* Mark not-dirty now in case we error out below */
     224           0 :         buf_state &= ~BM_DIRTY;
     225           0 :         pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     226             : 
     227           0 :         pgBufferUsage.local_blks_written++;
     228             :     }
     229             : 
     230             :     /*
     231             :      * lazy memory allocation: allocate space on first use of a buffer.
     232             :      */
     233       26286 :     if (LocalBufHdrGetBlock(bufHdr) == NULL)
     234             :     {
     235             :         /* Set pointer for use by BufferGetBlock() macro */
     236       26286 :         LocalBufHdrGetBlock(bufHdr) = GetLocalBufferStorage();
     237             :     }
     238             : 
     239             :     /*
     240             :      * Update the hash table: remove old entry, if any, and make new one.
     241             :      */
     242       26286 :     if (buf_state & BM_TAG_VALID)
     243             :     {
     244           0 :         hresult = (LocalBufferLookupEnt *)
     245           0 :             hash_search(LocalBufHash, (void *) &bufHdr->tag,
     246             :                         HASH_REMOVE, NULL);
     247           0 :         if (!hresult)           /* shouldn't happen */
     248           0 :             elog(ERROR, "local buffer hash table corrupted");
     249             :         /* mark buffer invalid just in case hash insert fails */
     250           0 :         CLEAR_BUFFERTAG(bufHdr->tag);
     251           0 :         buf_state &= ~(BM_VALID | BM_TAG_VALID);
     252           0 :         pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     253             :     }
     254             : 
     255       26286 :     hresult = (LocalBufferLookupEnt *)
     256       26286 :         hash_search(LocalBufHash, (void *) &newTag, HASH_ENTER, &found);
     257       26286 :     if (found)                  /* shouldn't happen */
     258           0 :         elog(ERROR, "local buffer hash table corrupted");
     259       26286 :     hresult->id = b;
     260             : 
     261             :     /*
     262             :      * it's all ours now.
     263             :      */
     264       26286 :     bufHdr->tag = newTag;
     265       26286 :     buf_state &= ~(BM_VALID | BM_DIRTY | BM_JUST_DIRTIED | BM_IO_ERROR);
     266       26286 :     buf_state |= BM_TAG_VALID;
     267       26286 :     buf_state &= ~BUF_USAGECOUNT_MASK;
     268       26286 :     buf_state += BUF_USAGECOUNT_ONE;
     269       26286 :     pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     270             : 
     271       26286 :     *foundPtr = false;
     272       26286 :     return bufHdr;
     273             : }
     274             : 
     275             : /*
     276             :  * MarkLocalBufferDirty -
     277             :  *    mark a local buffer dirty
     278             :  */
     279             : void
     280     2141124 : MarkLocalBufferDirty(Buffer buffer)
     281             : {
     282             :     int         bufid;
     283             :     BufferDesc *bufHdr;
     284             :     uint32      buf_state;
     285             : 
     286             :     Assert(BufferIsLocal(buffer));
     287             : 
     288             : #ifdef LBDEBUG
     289             :     fprintf(stderr, "LB DIRTY %d\n", buffer);
     290             : #endif
     291             : 
     292     2141124 :     bufid = -(buffer + 1);
     293             : 
     294             :     Assert(LocalRefCount[bufid] > 0);
     295             : 
     296     2141124 :     bufHdr = GetLocalBufferDescriptor(bufid);
     297             : 
     298     2141124 :     buf_state = pg_atomic_read_u32(&bufHdr->state);
     299             : 
     300     2141124 :     if (!(buf_state & BM_DIRTY))
     301       25614 :         pgBufferUsage.local_blks_dirtied++;
     302             : 
     303     2141124 :     buf_state |= BM_DIRTY;
     304             : 
     305     2141124 :     pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     306     2141124 : }
     307             : 
     308             : /*
     309             :  * DropRelFileNodeLocalBuffers
     310             :  *      This function removes from the buffer pool all the pages of the
     311             :  *      specified relation that have block numbers >= firstDelBlock.
     312             :  *      (In particular, with firstDelBlock = 0, all pages are removed.)
     313             :  *      Dirty pages are simply dropped, without bothering to write them
     314             :  *      out first.  Therefore, this is NOT rollback-able, and so should be
     315             :  *      used only with extreme caution!
     316             :  *
     317             :  *      See DropRelFileNodeBuffers in bufmgr.c for more notes.
     318             :  */
     319             : void
     320         204 : DropRelFileNodeLocalBuffers(RelFileNode rnode, ForkNumber forkNum,
     321             :                             BlockNumber firstDelBlock)
     322             : {
     323             :     int         i;
     324             : 
     325      172236 :     for (i = 0; i < NLocBuffer; i++)
     326             :     {
     327      172032 :         BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
     328             :         LocalBufferLookupEnt *hresult;
     329             :         uint32      buf_state;
     330             : 
     331      172032 :         buf_state = pg_atomic_read_u32(&bufHdr->state);
     332             : 
     333      172700 :         if ((buf_state & BM_TAG_VALID) &&
     334         724 :             RelFileNodeEquals(bufHdr->tag.rnode, rnode) &&
     335          56 :             bufHdr->tag.forkNum == forkNum &&
     336          28 :             bufHdr->tag.blockNum >= firstDelBlock)
     337             :         {
     338          28 :             if (LocalRefCount[i] != 0)
     339           0 :                 elog(ERROR, "block %u of %s is still referenced (local %u)",
     340             :                      bufHdr->tag.blockNum,
     341             :                      relpathbackend(bufHdr->tag.rnode, MyBackendId,
     342             :                                     bufHdr->tag.forkNum),
     343             :                      LocalRefCount[i]);
     344             :             /* Remove entry from hashtable */
     345          28 :             hresult = (LocalBufferLookupEnt *)
     346          28 :                 hash_search(LocalBufHash, (void *) &bufHdr->tag,
     347             :                             HASH_REMOVE, NULL);
     348          28 :             if (!hresult)       /* shouldn't happen */
     349           0 :                 elog(ERROR, "local buffer hash table corrupted");
     350             :             /* Mark buffer invalid */
     351          28 :             CLEAR_BUFFERTAG(bufHdr->tag);
     352          28 :             buf_state &= ~BUF_FLAG_MASK;
     353          28 :             buf_state &= ~BUF_USAGECOUNT_MASK;
     354          28 :             pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     355             :         }
     356             :     }
     357         204 : }
     358             : 
     359             : /*
     360             :  * DropRelFileNodeAllLocalBuffers
     361             :  *      This function removes from the buffer pool all pages of all forks
     362             :  *      of the specified relation.
     363             :  *
     364             :  *      See DropRelFileNodesAllBuffers in bufmgr.c for more notes.
     365             :  */
     366             : void
     367        4780 : DropRelFileNodeAllLocalBuffers(RelFileNode rnode)
     368             : {
     369             :     int         i;
     370             : 
     371     4735660 :     for (i = 0; i < NLocBuffer; i++)
     372             :     {
     373     4730880 :         BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
     374             :         LocalBufferLookupEnt *hresult;
     375             :         uint32      buf_state;
     376             : 
     377     4730880 :         buf_state = pg_atomic_read_u32(&bufHdr->state);
     378             : 
     379     4890172 :         if ((buf_state & BM_TAG_VALID) &&
     380      185550 :             RelFileNodeEquals(bufHdr->tag.rnode, rnode))
     381             :         {
     382       26258 :             if (LocalRefCount[i] != 0)
     383           0 :                 elog(ERROR, "block %u of %s is still referenced (local %u)",
     384             :                      bufHdr->tag.blockNum,
     385             :                      relpathbackend(bufHdr->tag.rnode, MyBackendId,
     386             :                                     bufHdr->tag.forkNum),
     387             :                      LocalRefCount[i]);
     388             :             /* Remove entry from hashtable */
     389       26258 :             hresult = (LocalBufferLookupEnt *)
     390       26258 :                 hash_search(LocalBufHash, (void *) &bufHdr->tag,
     391             :                             HASH_REMOVE, NULL);
     392       26258 :             if (!hresult)       /* shouldn't happen */
     393           0 :                 elog(ERROR, "local buffer hash table corrupted");
     394             :             /* Mark buffer invalid */
     395       26258 :             CLEAR_BUFFERTAG(bufHdr->tag);
     396       26258 :             buf_state &= ~BUF_FLAG_MASK;
     397       26258 :             buf_state &= ~BUF_USAGECOUNT_MASK;
     398       26258 :             pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
     399             :         }
     400             :     }
     401        4780 : }
     402             : 
     403             : /*
     404             :  * InitLocalBuffers -
     405             :  *    init the local buffer cache. Since most queries (esp. multi-user ones)
     406             :  *    don't involve local buffers, we delay allocating actual memory for the
     407             :  *    buffers until we need them; just make the buffer headers here.
     408             :  */
     409             : static void
     410         566 : InitLocalBuffers(void)
     411             : {
     412         566 :     int         nbufs = num_temp_buffers;
     413             :     HASHCTL     info;
     414             :     int         i;
     415             : 
     416             :     /*
     417             :      * Parallel workers can't access data in temporary tables, because they
     418             :      * have no visibility into the local buffers of their leader.  This is a
     419             :      * convenient, low-cost place to provide a backstop check for that.  Note
     420             :      * that we don't wish to prevent a parallel worker from accessing catalog
     421             :      * metadata about a temp table, so checks at higher levels would be
     422             :      * inappropriate.
     423             :      */
     424         566 :     if (IsParallelWorker())
     425           0 :         ereport(ERROR,
     426             :                 (errcode(ERRCODE_INVALID_TRANSACTION_STATE),
     427             :                  errmsg("cannot access temporary tables during a parallel operation")));
     428             : 
     429             :     /* Allocate and zero buffer headers and auxiliary arrays */
     430         566 :     LocalBufferDescriptors = (BufferDesc *) calloc(nbufs, sizeof(BufferDesc));
     431         566 :     LocalBufferBlockPointers = (Block *) calloc(nbufs, sizeof(Block));
     432         566 :     LocalRefCount = (int32 *) calloc(nbufs, sizeof(int32));
     433         566 :     if (!LocalBufferDescriptors || !LocalBufferBlockPointers || !LocalRefCount)
     434           0 :         ereport(FATAL,
     435             :                 (errcode(ERRCODE_OUT_OF_MEMORY),
     436             :                  errmsg("out of memory")));
     437             : 
     438         566 :     nextFreeLocalBuf = 0;
     439             : 
     440             :     /* initialize fields that need to start off nonzero */
     441      580150 :     for (i = 0; i < nbufs; i++)
     442             :     {
     443      579584 :         BufferDesc *buf = GetLocalBufferDescriptor(i);
     444             : 
     445             :         /*
     446             :          * negative to indicate local buffer. This is tricky: shared buffers
     447             :          * start with 0. We have to start with -2. (Note that the routine
     448             :          * BufferDescriptorGetBuffer adds 1 to buf_id so our first buffer id
     449             :          * is -1.)
     450             :          */
     451      579584 :         buf->buf_id = -i - 2;
     452             : 
     453             :         /*
     454             :          * Intentionally do not initialize the buffer's atomic variable
     455             :          * (besides zeroing the underlying memory above). That way we get
     456             :          * errors on platforms without atomics, if somebody (re-)introduces
     457             :          * atomic operations for local buffers.
     458             :          */
     459             :     }
     460             : 
     461             :     /* Create the lookup hash table */
     462         566 :     MemSet(&info, 0, sizeof(info));
     463         566 :     info.keysize = sizeof(BufferTag);
     464         566 :     info.entrysize = sizeof(LocalBufferLookupEnt);
     465             : 
     466         566 :     LocalBufHash = hash_create("Local Buffer Lookup Table",
     467             :                                nbufs,
     468             :                                &info,
     469             :                                HASH_ELEM | HASH_BLOBS);
     470             : 
     471         566 :     if (!LocalBufHash)
     472           0 :         elog(ERROR, "could not initialize local buffer hash table");
     473             : 
     474             :     /* Initialization done, mark buffers allocated */
     475         566 :     NLocBuffer = nbufs;
     476         566 : }
     477             : 
     478             : /*
     479             :  * GetLocalBufferStorage - allocate memory for a local buffer
     480             :  *
     481             :  * The idea of this function is to aggregate our requests for storage
     482             :  * so that the memory manager doesn't see a whole lot of relatively small
     483             :  * requests.  Since we'll never give back a local buffer once it's created
     484             :  * within a particular process, no point in burdening memmgr with separately
     485             :  * managed chunks.
     486             :  */
     487             : static Block
     488       26286 : GetLocalBufferStorage(void)
     489             : {
     490             :     static char *cur_block = NULL;
     491             :     static int  next_buf_in_block = 0;
     492             :     static int  num_bufs_in_block = 0;
     493             :     static int  total_bufs_allocated = 0;
     494             :     static MemoryContext LocalBufferContext = NULL;
     495             : 
     496             :     char       *this_buf;
     497             : 
     498             :     Assert(total_bufs_allocated < NLocBuffer);
     499             : 
     500       26286 :     if (next_buf_in_block >= num_bufs_in_block)
     501             :     {
     502             :         /* Need to make a new request to memmgr */
     503             :         int         num_bufs;
     504             : 
     505             :         /*
     506             :          * We allocate local buffers in a context of their own, so that the
     507             :          * space eaten for them is easily recognizable in MemoryContextStats
     508             :          * output.  Create the context on first use.
     509             :          */
     510        1318 :         if (LocalBufferContext == NULL)
     511         566 :             LocalBufferContext =
     512         566 :                 AllocSetContextCreate(TopMemoryContext,
     513             :                                       "LocalBufferContext",
     514             :                                       ALLOCSET_DEFAULT_SIZES);
     515             : 
     516             :         /* Start with a 16-buffer request; subsequent ones double each time */
     517        1318 :         num_bufs = Max(num_bufs_in_block * 2, 16);
     518             :         /* But not more than what we need for all remaining local bufs */
     519        1318 :         num_bufs = Min(num_bufs, NLocBuffer - total_bufs_allocated);
     520             :         /* And don't overflow MaxAllocSize, either */
     521        1318 :         num_bufs = Min(num_bufs, MaxAllocSize / BLCKSZ);
     522             : 
     523        1318 :         cur_block = (char *) MemoryContextAlloc(LocalBufferContext,
     524        1318 :                                                 num_bufs * BLCKSZ);
     525        1318 :         next_buf_in_block = 0;
     526        1318 :         num_bufs_in_block = num_bufs;
     527             :     }
     528             : 
     529             :     /* Allocate next buffer in current memory block */
     530       26286 :     this_buf = cur_block + next_buf_in_block * BLCKSZ;
     531       26286 :     next_buf_in_block++;
     532       26286 :     total_bufs_allocated++;
     533             : 
     534       26286 :     return (Block) this_buf;
     535             : }
     536             : 
     537             : /*
     538             :  * CheckForLocalBufferLeaks - ensure this backend holds no local buffer pins
     539             :  *
     540             :  * This is just like CheckForBufferLeaks(), but for local buffers.
     541             :  */
     542             : static void
     543      470118 : CheckForLocalBufferLeaks(void)
     544             : {
     545             : #ifdef USE_ASSERT_CHECKING
     546             :     if (LocalRefCount)
     547             :     {
     548             :         int         RefCountErrors = 0;
     549             :         int         i;
     550             : 
     551             :         for (i = 0; i < NLocBuffer; i++)
     552             :         {
     553             :             if (LocalRefCount[i] != 0)
     554             :             {
     555             :                 Buffer      b = -i - 1;
     556             : 
     557             :                 PrintBufferLeakWarning(b);
     558             :                 RefCountErrors++;
     559             :             }
     560             :         }
     561             :         Assert(RefCountErrors == 0);
     562             :     }
     563             : #endif
     564      470118 : }
     565             : 
     566             : /*
     567             :  * AtEOXact_LocalBuffers - clean up at end of transaction.
     568             :  *
     569             :  * This is just like AtEOXact_Buffers, but for local buffers.
     570             :  */
     571             : void
     572      458438 : AtEOXact_LocalBuffers(bool isCommit)
     573             : {
     574      458438 :     CheckForLocalBufferLeaks();
     575      458438 : }
     576             : 
     577             : /*
     578             :  * AtProcExit_LocalBuffers - ensure we have dropped pins during backend exit.
     579             :  *
     580             :  * This is just like AtProcExit_Buffers, but for local buffers.
     581             :  */
     582             : void
     583       11680 : AtProcExit_LocalBuffers(void)
     584             : {
     585             :     /*
     586             :      * We shouldn't be holding any remaining pins; if we are, and assertions
     587             :      * aren't enabled, we'll fail later in DropRelFileNodeBuffers while trying
     588             :      * to drop the temp rels.
     589             :      */
     590       11680 :     CheckForLocalBufferLeaks();
     591       11680 : }

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