PostgreSQL Source Code  git master
logtape.c File Reference
#include "postgres.h"
#include "storage/buffile.h"
#include "utils/builtins.h"
#include "utils/logtape.h"
#include "utils/memdebug.h"
#include "utils/memutils.h"
Include dependency graph for logtape.c:

Go to the source code of this file.

Data Structures

struct  TapeBlockTrailer
 
struct  LogicalTape
 
struct  LogicalTapeSet
 

Macros

#define TapeBlockPayloadSize   (BLCKSZ - sizeof(TapeBlockTrailer))
 
#define TapeBlockGetTrailer(buf)   ((TapeBlockTrailer *) ((char *) buf + TapeBlockPayloadSize))
 
#define TapeBlockIsLast(buf)   (TapeBlockGetTrailer(buf)->next < 0)
 
#define TapeBlockGetNBytes(buf)
 
#define TapeBlockSetNBytes(buf, nbytes)   (TapeBlockGetTrailer(buf)->next = -(nbytes))
 

Typedefs

typedef struct TapeBlockTrailer TapeBlockTrailer
 
typedef struct LogicalTape LogicalTape
 

Functions

static void ltsWriteBlock (LogicalTapeSet *lts, long blocknum, void *buffer)
 
static void ltsReadBlock (LogicalTapeSet *lts, long blocknum, void *buffer)
 
static long ltsGetFreeBlock (LogicalTapeSet *lts)
 
static void ltsReleaseBlock (LogicalTapeSet *lts, long blocknum)
 
static void ltsConcatWorkerTapes (LogicalTapeSet *lts, TapeShare *shared, SharedFileSet *fileset)
 
static bool ltsReadFillBuffer (LogicalTapeSet *lts, LogicalTape *lt)
 
static int freeBlocks_cmp (const void *a, const void *b)
 
LogicalTapeSetLogicalTapeSetCreate (int ntapes, TapeShare *shared, SharedFileSet *fileset, int worker)
 
void LogicalTapeSetClose (LogicalTapeSet *lts)
 
void LogicalTapeSetForgetFreeSpace (LogicalTapeSet *lts)
 
void LogicalTapeWrite (LogicalTapeSet *lts, int tapenum, void *ptr, size_t size)
 
void LogicalTapeRewindForRead (LogicalTapeSet *lts, int tapenum, size_t buffer_size)
 
void LogicalTapeRewindForWrite (LogicalTapeSet *lts, int tapenum)
 
size_t LogicalTapeRead (LogicalTapeSet *lts, int tapenum, void *ptr, size_t size)
 
void LogicalTapeFreeze (LogicalTapeSet *lts, int tapenum, TapeShare *share)
 
size_t LogicalTapeBackspace (LogicalTapeSet *lts, int tapenum, size_t size)
 
void LogicalTapeSeek (LogicalTapeSet *lts, int tapenum, long blocknum, int offset)
 
void LogicalTapeTell (LogicalTapeSet *lts, int tapenum, long *blocknum, int *offset)
 
long LogicalTapeSetBlocks (LogicalTapeSet *lts)
 

Macro Definition Documentation

◆ TapeBlockGetNBytes

#define TapeBlockGetNBytes (   buf)
Value:
#define TapeBlockIsLast(buf)
Definition: logtape.c:110
#define TapeBlockPayloadSize
Definition: logtape.c:106
static char * buf
Definition: pg_test_fsync.c:67
#define TapeBlockGetTrailer(buf)
Definition: logtape.c:107

Definition at line 111 of file logtape.c.

Referenced by LogicalTapeFreeze(), and ltsReadFillBuffer().

◆ TapeBlockGetTrailer

#define TapeBlockGetTrailer (   buf)    ((TapeBlockTrailer *) ((char *) buf + TapeBlockPayloadSize))

◆ TapeBlockIsLast

#define TapeBlockIsLast (   buf)    (TapeBlockGetTrailer(buf)->next < 0)

Definition at line 110 of file logtape.c.

Referenced by LogicalTapeFreeze(), and ltsReadFillBuffer().

◆ TapeBlockPayloadSize

#define TapeBlockPayloadSize   (BLCKSZ - sizeof(TapeBlockTrailer))

Definition at line 106 of file logtape.c.

Referenced by LogicalTapeBackspace(), LogicalTapeSeek(), and LogicalTapeWrite().

◆ TapeBlockSetNBytes

#define TapeBlockSetNBytes (   buf,
  nbytes 
)    (TapeBlockGetTrailer(buf)->next = -(nbytes))

Definition at line 114 of file logtape.c.

Referenced by LogicalTapeFreeze(), and LogicalTapeRewindForRead().

Typedef Documentation

◆ LogicalTape

◆ TapeBlockTrailer

Function Documentation

◆ freeBlocks_cmp()

static int freeBlocks_cmp ( const void *  a,
const void *  b 
)
static

Definition at line 328 of file logtape.c.

Referenced by ltsGetFreeBlock().

329 {
330  long ablk = *((const long *) a);
331  long bblk = *((const long *) b);
332 
333  /* can't just subtract because long might be wider than int */
334  if (ablk < bblk)
335  return 1;
336  if (ablk > bblk)
337  return -1;
338  return 0;
339 }

◆ LogicalTapeBackspace()

size_t LogicalTapeBackspace ( LogicalTapeSet lts,
int  tapenum,
size_t  size 
)

Definition at line 964 of file logtape.c.

References Assert, LogicalTape::buffer, LogicalTape::buffer_size, LogicalTape::curBlockNumber, elog, ERROR, LogicalTape::firstBlockNumber, LogicalTape::frozen, ltsReadBlock(), LogicalTape::nbytes, LogicalTape::nextBlockNumber, LogicalTape::pos, TapeBlockTrailer::prev, TapeBlockGetTrailer, TapeBlockPayloadSize, and LogicalTapeSet::tapes.

Referenced by tuplesort_gettuple_common().

965 {
966  LogicalTape *lt;
967  size_t seekpos = 0;
968 
969  Assert(tapenum >= 0 && tapenum < lts->nTapes);
970  lt = &lts->tapes[tapenum];
971  Assert(lt->frozen);
972  Assert(lt->buffer_size == BLCKSZ);
973 
974  /*
975  * Easy case for seek within current block.
976  */
977  if (size <= (size_t) lt->pos)
978  {
979  lt->pos -= (int) size;
980  return size;
981  }
982 
983  /*
984  * Not-so-easy case, have to walk back the chain of blocks. This
985  * implementation would be pretty inefficient for long seeks, but we
986  * really aren't doing that (a seek over one tuple is typical).
987  */
988  seekpos = (size_t) lt->pos; /* part within this block */
989  while (size > seekpos)
990  {
991  long prev = TapeBlockGetTrailer(lt->buffer)->prev;
992 
993  if (prev == -1L)
994  {
995  /* Tried to back up beyond the beginning of tape. */
996  if (lt->curBlockNumber != lt->firstBlockNumber)
997  elog(ERROR, "unexpected end of tape");
998  lt->pos = 0;
999  return seekpos;
1000  }
1001 
1002  ltsReadBlock(lts, prev, (void *) lt->buffer);
1003 
1004  if (TapeBlockGetTrailer(lt->buffer)->next != lt->curBlockNumber)
1005  elog(ERROR, "broken tape, next of block %ld is %ld, expected %ld",
1006  prev,
1007  TapeBlockGetTrailer(lt->buffer)->next,
1008  lt->curBlockNumber);
1009 
1011  lt->curBlockNumber = prev;
1012  lt->nextBlockNumber = TapeBlockGetTrailer(lt->buffer)->next;
1013 
1014  seekpos += TapeBlockPayloadSize;
1015  }
1016 
1017  /*
1018  * 'seekpos' can now be greater than 'size', because it points to the
1019  * beginning the target block. The difference is the position within the
1020  * page.
1021  */
1022  lt->pos = seekpos - size;
1023  return size;
1024 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
#define TapeBlockPayloadSize
Definition: logtape.c:106
bool frozen
Definition: logtape.c:131
long nextBlockNumber
Definition: logtape.c:147
#define ERROR
Definition: elog.h:43
int nbytes
Definition: logtape.c:157
long firstBlockNumber
Definition: logtape.c:145
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
char * buffer
Definition: logtape.c:153
#define elog
Definition: elog.h:219
int buffer_size
Definition: logtape.c:154
#define TapeBlockGetTrailer(buf)
Definition: logtape.c:107
static void ltsReadBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:270

◆ LogicalTapeFreeze()

void LogicalTapeFreeze ( LogicalTapeSet lts,
int  tapenum,
TapeShare share 
)

Definition at line 880 of file logtape.c.

References Assert, LogicalTape::buffer, LogicalTape::buffer_size, BufFileExportShared(), LogicalTape::curBlockNumber, LogicalTape::dirty, TapeShare::firstblocknumber, LogicalTape::firstBlockNumber, LogicalTape::frozen, ltsReadBlock(), ltsWriteBlock(), LogicalTape::nbytes, LogicalTape::nextBlockNumber, LogicalTape::offsetBlockNumber, palloc(), LogicalTapeSet::pfile, pfree(), LogicalTape::pos, TapeBlockGetNBytes, TapeBlockGetTrailer, TapeBlockIsLast, TapeBlockSetNBytes, LogicalTapeSet::tapes, VALGRIND_MAKE_MEM_DEFINED, and LogicalTape::writing.

Referenced by mergeruns(), and worker_freeze_result_tape().

881 {
882  LogicalTape *lt;
883 
884  Assert(tapenum >= 0 && tapenum < lts->nTapes);
885  lt = &lts->tapes[tapenum];
886  Assert(lt->writing);
887  Assert(lt->offsetBlockNumber == 0L);
888 
889  /*
890  * Completion of a write phase. Flush last partial data block, and rewind
891  * for nondestructive read.
892  */
893  if (lt->dirty)
894  {
895  /*
896  * As long as we've filled the buffer at least once, its contents are
897  * entirely defined from valgrind's point of view, even though
898  * contents beyond the current end point may be stale. But it's
899  * possible - at least in the case of a parallel sort - to sort such
900  * small amount of data that we do not fill the buffer even once. Tell
901  * valgrind that its contents are defined, so it doesn't bleat.
902  */
904  lt->buffer_size - lt->nbytes);
905 
906  TapeBlockSetNBytes(lt->buffer, lt->nbytes);
907  ltsWriteBlock(lts, lt->curBlockNumber, (void *) lt->buffer);
908  lt->writing = false;
909  }
910  lt->writing = false;
911  lt->frozen = true;
912 
913  /*
914  * The seek and backspace functions assume a single block read buffer.
915  * That's OK with current usage. A larger buffer is helpful to make the
916  * read pattern of the backing file look more sequential to the OS, when
917  * we're reading from multiple tapes. But at the end of a sort, when a
918  * tape is frozen, we only read from a single tape anyway.
919  */
920  if (!lt->buffer || lt->buffer_size != BLCKSZ)
921  {
922  if (lt->buffer)
923  pfree(lt->buffer);
924  lt->buffer = palloc(BLCKSZ);
925  lt->buffer_size = BLCKSZ;
926  }
927 
928  /* Read the first block, or reset if tape is empty */
930  lt->pos = 0;
931  lt->nbytes = 0;
932 
933  if (lt->firstBlockNumber == -1L)
934  lt->nextBlockNumber = -1L;
935  ltsReadBlock(lts, lt->curBlockNumber, (void *) lt->buffer);
936  if (TapeBlockIsLast(lt->buffer))
937  lt->nextBlockNumber = -1L;
938  else
939  lt->nextBlockNumber = TapeBlockGetTrailer(lt->buffer)->next;
940  lt->nbytes = TapeBlockGetNBytes(lt->buffer);
941 
942  /* Handle extra steps when caller is to share its tapeset */
943  if (share)
944  {
946  share->firstblocknumber = lt->firstBlockNumber;
947  }
948 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
#define VALGRIND_MAKE_MEM_DEFINED(addr, size)
Definition: memdebug.h:26
#define TapeBlockIsLast(buf)
Definition: logtape.c:110
long offsetBlockNumber
Definition: logtape.c:148
BufFile * pfile
Definition: logtape.c:168
long firstblocknumber
Definition: logtape.h:50
bool frozen
Definition: logtape.c:131
long nextBlockNumber
Definition: logtape.c:147
bool writing
Definition: logtape.c:130
bool dirty
Definition: logtape.c:132
void pfree(void *pointer)
Definition: mcxt.c:1031
int nbytes
Definition: logtape.c:157
long firstBlockNumber
Definition: logtape.c:145
#define TapeBlockSetNBytes(buf, nbytes)
Definition: logtape.c:114
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
void BufFileExportShared(BufFile *file)
Definition: buffile.c:379
#define TapeBlockGetNBytes(buf)
Definition: logtape.c:111
char * buffer
Definition: logtape.c:153
void * palloc(Size size)
Definition: mcxt.c:924
int buffer_size
Definition: logtape.c:154
static void ltsWriteBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:222
#define TapeBlockGetTrailer(buf)
Definition: logtape.c:107
static void ltsReadBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:270

◆ LogicalTapeRead()

size_t LogicalTapeRead ( LogicalTapeSet lts,
int  tapenum,
void *  ptr,
size_t  size 
)

Definition at line 826 of file logtape.c.

References Assert, LogicalTape::buffer, ltsReadFillBuffer(), LogicalTape::nbytes, LogicalTape::pos, LogicalTapeSet::tapes, and LogicalTape::writing.

Referenced by getlen().

828 {
829  LogicalTape *lt;
830  size_t nread = 0;
831  size_t nthistime;
832 
833  Assert(tapenum >= 0 && tapenum < lts->nTapes);
834  lt = &lts->tapes[tapenum];
835  Assert(!lt->writing);
836 
837  while (size > 0)
838  {
839  if (lt->pos >= lt->nbytes)
840  {
841  /* Try to load more data into buffer. */
842  if (!ltsReadFillBuffer(lts, lt))
843  break; /* EOF */
844  }
845 
846  nthistime = lt->nbytes - lt->pos;
847  if (nthistime > size)
848  nthistime = size;
849  Assert(nthistime > 0);
850 
851  memcpy(ptr, lt->buffer + lt->pos, nthistime);
852 
853  lt->pos += nthistime;
854  ptr = (void *) ((char *) ptr + nthistime);
855  size -= nthistime;
856  nread += nthistime;
857  }
858 
859  return nread;
860 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
static bool ltsReadFillBuffer(LogicalTapeSet *lts, LogicalTape *lt)
Definition: logtape.c:286
bool writing
Definition: logtape.c:130
int nbytes
Definition: logtape.c:157
#define Assert(condition)
Definition: c.h:699
char * buffer
Definition: logtape.c:153

◆ LogicalTapeRewindForRead()

void LogicalTapeRewindForRead ( LogicalTapeSet lts,
int  tapenum,
size_t  buffer_size 
)

Definition at line 713 of file logtape.c.

References Assert, LogicalTape::buffer, LogicalTape::buffer_size, LogicalTape::curBlockNumber, LogicalTape::dirty, LogicalTape::firstBlockNumber, LogicalTape::frozen, ltsReadFillBuffer(), ltsWriteBlock(), LogicalTape::max_size, LogicalTape::nbytes, LogicalTape::nextBlockNumber, palloc(), pfree(), LogicalTape::pos, TapeBlockSetNBytes, LogicalTapeSet::tapes, VALGRIND_MAKE_MEM_DEFINED, and LogicalTape::writing.

Referenced by mergeruns(), and tuplesort_rescan().

714 {
715  LogicalTape *lt;
716 
717  Assert(tapenum >= 0 && tapenum < lts->nTapes);
718  lt = &lts->tapes[tapenum];
719 
720  /*
721  * Round and cap buffer_size if needed.
722  */
723  if (lt->frozen)
724  buffer_size = BLCKSZ;
725  else
726  {
727  /* need at least one block */
728  if (buffer_size < BLCKSZ)
729  buffer_size = BLCKSZ;
730 
731  /* palloc() larger than max_size is unlikely to be helpful */
732  if (buffer_size > lt->max_size)
733  buffer_size = lt->max_size;
734 
735  /* round down to BLCKSZ boundary */
736  buffer_size -= buffer_size % BLCKSZ;
737  }
738 
739  if (lt->writing)
740  {
741  /*
742  * Completion of a write phase. Flush last partial data block, and
743  * rewind for normal (destructive) read.
744  */
745  if (lt->dirty)
746  {
747  /*
748  * As long as we've filled the buffer at least once, its contents
749  * are entirely defined from valgrind's point of view, even though
750  * contents beyond the current end point may be stale. But it's
751  * possible - at least in the case of a parallel sort - to sort
752  * such small amount of data that we do not fill the buffer even
753  * once. Tell valgrind that its contents are defined, so it
754  * doesn't bleat.
755  */
757  lt->buffer_size - lt->nbytes);
758 
759  TapeBlockSetNBytes(lt->buffer, lt->nbytes);
760  ltsWriteBlock(lts, lt->curBlockNumber, (void *) lt->buffer);
761  }
762  lt->writing = false;
763  }
764  else
765  {
766  /*
767  * This is only OK if tape is frozen; we rewind for (another) read
768  * pass.
769  */
770  Assert(lt->frozen);
771  }
772 
773  /* Allocate a read buffer (unless the tape is empty) */
774  if (lt->buffer)
775  pfree(lt->buffer);
776  lt->buffer = NULL;
777  lt->buffer_size = 0;
778  if (lt->firstBlockNumber != -1L)
779  {
780  lt->buffer = palloc(buffer_size);
781  lt->buffer_size = buffer_size;
782  }
783 
784  /* Read the first block, or reset if tape is empty */
786  lt->pos = 0;
787  lt->nbytes = 0;
788  ltsReadFillBuffer(lts, lt);
789 }
int max_size
Definition: logtape.c:155
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
#define VALGRIND_MAKE_MEM_DEFINED(addr, size)
Definition: memdebug.h:26
static bool ltsReadFillBuffer(LogicalTapeSet *lts, LogicalTape *lt)
Definition: logtape.c:286
bool frozen
Definition: logtape.c:131
long nextBlockNumber
Definition: logtape.c:147
bool writing
Definition: logtape.c:130
bool dirty
Definition: logtape.c:132
void pfree(void *pointer)
Definition: mcxt.c:1031
int nbytes
Definition: logtape.c:157
long firstBlockNumber
Definition: logtape.c:145
#define TapeBlockSetNBytes(buf, nbytes)
Definition: logtape.c:114
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
char * buffer
Definition: logtape.c:153
void * palloc(Size size)
Definition: mcxt.c:924
int buffer_size
Definition: logtape.c:154
static void ltsWriteBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:222

◆ LogicalTapeRewindForWrite()

void LogicalTapeRewindForWrite ( LogicalTapeSet lts,
int  tapenum 
)

Definition at line 800 of file logtape.c.

References Assert, LogicalTape::buffer, LogicalTape::buffer_size, LogicalTape::curBlockNumber, LogicalTape::dirty, LogicalTape::firstBlockNumber, LogicalTape::frozen, LogicalTape::nbytes, pfree(), LogicalTape::pos, LogicalTapeSet::tapes, and LogicalTape::writing.

Referenced by mergeruns(), and tuplesort_gettuple_common().

801 {
802  LogicalTape *lt;
803 
804  Assert(tapenum >= 0 && tapenum < lts->nTapes);
805  lt = &lts->tapes[tapenum];
806 
807  Assert(!lt->writing && !lt->frozen);
808  lt->writing = true;
809  lt->dirty = false;
810  lt->firstBlockNumber = -1L;
811  lt->curBlockNumber = -1L;
812  lt->pos = 0;
813  lt->nbytes = 0;
814  if (lt->buffer)
815  pfree(lt->buffer);
816  lt->buffer = NULL;
817  lt->buffer_size = 0;
818 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
bool frozen
Definition: logtape.c:131
bool writing
Definition: logtape.c:130
bool dirty
Definition: logtape.c:132
void pfree(void *pointer)
Definition: mcxt.c:1031
int nbytes
Definition: logtape.c:157
long firstBlockNumber
Definition: logtape.c:145
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
char * buffer
Definition: logtape.c:153
int buffer_size
Definition: logtape.c:154

◆ LogicalTapeSeek()

void LogicalTapeSeek ( LogicalTapeSet lts,
int  tapenum,
long  blocknum,
int  offset 
)

Definition at line 1035 of file logtape.c.

References Assert, LogicalTape::buffer, LogicalTape::buffer_size, LogicalTape::curBlockNumber, elog, ERROR, LogicalTape::frozen, ltsReadBlock(), LogicalTape::nbytes, LogicalTape::nextBlockNumber, LogicalTape::pos, TapeBlockGetTrailer, TapeBlockPayloadSize, and LogicalTapeSet::tapes.

Referenced by tuplesort_restorepos().

1037 {
1038  LogicalTape *lt;
1039 
1040  Assert(tapenum >= 0 && tapenum < lts->nTapes);
1041  lt = &lts->tapes[tapenum];
1042  Assert(lt->frozen);
1043  Assert(offset >= 0 && offset <= TapeBlockPayloadSize);
1044  Assert(lt->buffer_size == BLCKSZ);
1045 
1046  if (blocknum != lt->curBlockNumber)
1047  {
1048  ltsReadBlock(lts, blocknum, (void *) lt->buffer);
1049  lt->curBlockNumber = blocknum;
1051  lt->nextBlockNumber = TapeBlockGetTrailer(lt->buffer)->next;
1052  }
1053 
1054  if (offset > lt->nbytes)
1055  elog(ERROR, "invalid tape seek position");
1056  lt->pos = offset;
1057 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
#define TapeBlockPayloadSize
Definition: logtape.c:106
bool frozen
Definition: logtape.c:131
long nextBlockNumber
Definition: logtape.c:147
#define ERROR
Definition: elog.h:43
int nbytes
Definition: logtape.c:157
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
char * buffer
Definition: logtape.c:153
#define elog
Definition: elog.h:219
int buffer_size
Definition: logtape.c:154
#define TapeBlockGetTrailer(buf)
Definition: logtape.c:107
static void ltsReadBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:270

◆ LogicalTapeSetBlocks()

long LogicalTapeSetBlocks ( LogicalTapeSet lts)

Definition at line 1086 of file logtape.c.

References LogicalTapeSet::nBlocksAllocated, and LogicalTapeSet::nHoleBlocks.

Referenced by tuplesort_end(), and tuplesort_get_stats().

1087 {
1088  return lts->nBlocksAllocated - lts->nHoleBlocks;
1089 }
long nHoleBlocks
Definition: logtape.c:182
long nBlocksAllocated
Definition: logtape.c:180

◆ LogicalTapeSetClose()

void LogicalTapeSetClose ( LogicalTapeSet lts)

Definition at line 588 of file logtape.c.

References LogicalTape::buffer, BufFileClose(), LogicalTapeSet::freeBlocks, i, LogicalTapeSet::nTapes, LogicalTapeSet::pfile, pfree(), and LogicalTapeSet::tapes.

Referenced by tuplesort_end().

589 {
590  LogicalTape *lt;
591  int i;
592 
593  BufFileClose(lts->pfile);
594  for (i = 0; i < lts->nTapes; i++)
595  {
596  lt = &lts->tapes[i];
597  if (lt->buffer)
598  pfree(lt->buffer);
599  }
600  pfree(lts->freeBlocks);
601  pfree(lts);
602 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
BufFile * pfile
Definition: logtape.c:168
void BufFileClose(BufFile *file)
Definition: buffile.c:397
long * freeBlocks
Definition: logtape.c:199
void pfree(void *pointer)
Definition: mcxt.c:1031
char * buffer
Definition: logtape.c:153
int i

◆ LogicalTapeSetCreate()

LogicalTapeSet* LogicalTapeSetCreate ( int  ntapes,
TapeShare shared,
SharedFileSet fileset,
int  worker 
)

Definition at line 514 of file logtape.c.

References Assert, LogicalTapeSet::blocksSorted, LogicalTape::buffer, LogicalTape::buffer_size, BufFileCreateShared(), BufFileCreateTemp(), LogicalTape::curBlockNumber, LogicalTape::dirty, filename, LogicalTape::firstBlockNumber, LogicalTapeSet::forgetFreeSpace, LogicalTapeSet::freeBlocks, LogicalTapeSet::freeBlocksLen, LogicalTape::frozen, i, ltsConcatWorkerTapes(), LogicalTape::max_size, MaxAllocSize, MAXPGPATH, LogicalTapeSet::nBlocksAllocated, LogicalTapeSet::nBlocksWritten, LogicalTape::nbytes, LogicalTape::nextBlockNumber, LogicalTapeSet::nFreeBlocks, LogicalTapeSet::nHoleBlocks, LogicalTapeSet::nTapes, LogicalTape::offsetBlockNumber, offsetof, palloc(), LogicalTapeSet::pfile, pg_itoa(), LogicalTape::pos, LogicalTapeSet::tapes, and LogicalTape::writing.

Referenced by inittapes(), and leader_takeover_tapes().

516 {
517  LogicalTapeSet *lts;
518  LogicalTape *lt;
519  int i;
520 
521  /*
522  * Create top-level struct including per-tape LogicalTape structs.
523  */
524  Assert(ntapes > 0);
525  lts = (LogicalTapeSet *) palloc(offsetof(LogicalTapeSet, tapes) +
526  ntapes * sizeof(LogicalTape));
527  lts->nBlocksAllocated = 0L;
528  lts->nBlocksWritten = 0L;
529  lts->nHoleBlocks = 0L;
530  lts->forgetFreeSpace = false;
531  lts->blocksSorted = true; /* a zero-length array is sorted ... */
532  lts->freeBlocksLen = 32; /* reasonable initial guess */
533  lts->freeBlocks = (long *) palloc(lts->freeBlocksLen * sizeof(long));
534  lts->nFreeBlocks = 0;
535  lts->nTapes = ntapes;
536 
537  /*
538  * Initialize per-tape structs. Note we allocate the I/O buffer and the
539  * first block for a tape only when it is first actually written to. This
540  * avoids wasting memory space when tuplesort.c overestimates the number
541  * of tapes needed.
542  */
543  for (i = 0; i < ntapes; i++)
544  {
545  lt = &lts->tapes[i];
546  lt->writing = true;
547  lt->frozen = false;
548  lt->dirty = false;
549  lt->firstBlockNumber = -1L;
550  lt->curBlockNumber = -1L;
551  lt->nextBlockNumber = -1L;
552  lt->offsetBlockNumber = 0L;
553  lt->buffer = NULL;
554  lt->buffer_size = 0;
555  /* palloc() larger than MaxAllocSize would fail */
556  lt->max_size = MaxAllocSize;
557  lt->pos = 0;
558  lt->nbytes = 0;
559  }
560 
561  /*
562  * Create temp BufFile storage as required.
563  *
564  * Leader concatenates worker tapes, which requires special adjustment to
565  * final tapeset data. Things are simpler for the worker case and the
566  * serial case, though. They are generally very similar -- workers use a
567  * shared fileset, whereas serial sorts use a conventional serial BufFile.
568  */
569  if (shared)
570  ltsConcatWorkerTapes(lts, shared, fileset);
571  else if (fileset)
572  {
573  char filename[MAXPGPATH];
574 
575  pg_itoa(worker, filename);
576  lts->pfile = BufFileCreateShared(fileset, filename);
577  }
578  else
579  lts->pfile = BufFileCreateTemp(false);
580 
581  return lts;
582 }
int max_size
Definition: logtape.c:155
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
int nFreeBlocks
Definition: logtape.c:200
long offsetBlockNumber
Definition: logtape.c:148
long nBlocksWritten
Definition: logtape.c:181
int freeBlocksLen
Definition: logtape.c:201
BufFile * pfile
Definition: logtape.c:168
bool frozen
Definition: logtape.c:131
long nextBlockNumber
Definition: logtape.c:147
bool writing
Definition: logtape.c:130
long * freeBlocks
Definition: logtape.c:199
bool dirty
Definition: logtape.c:132
BufFile * BufFileCreateTemp(bool interXact)
Definition: buffile.c:182
#define MAXPGPATH
BufFile * BufFileCreateShared(SharedFileSet *fileset, const char *name)
Definition: buffile.c:245
long nHoleBlocks
Definition: logtape.c:182
int nbytes
Definition: logtape.c:157
void pg_itoa(int16 i, char *a)
Definition: numutils.c:120
#define MaxAllocSize
Definition: memutils.h:40
long firstBlockNumber
Definition: logtape.c:145
static void ltsConcatWorkerTapes(LogicalTapeSet *lts, TapeShare *shared, SharedFileSet *fileset)
Definition: logtape.c:409
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
char * buffer
Definition: logtape.c:153
static char * filename
Definition: pg_dumpall.c:87
void * palloc(Size size)
Definition: mcxt.c:924
bool forgetFreeSpace
Definition: logtape.c:197
int i
struct LogicalTape LogicalTape
bool blocksSorted
Definition: logtape.c:198
long nBlocksAllocated
Definition: logtape.c:180
int buffer_size
Definition: logtape.c:154
#define offsetof(type, field)
Definition: c.h:622

◆ LogicalTapeSetForgetFreeSpace()

void LogicalTapeSetForgetFreeSpace ( LogicalTapeSet lts)

Definition at line 614 of file logtape.c.

References LogicalTapeSet::forgetFreeSpace.

Referenced by mergeruns().

615 {
616  lts->forgetFreeSpace = true;
617 }
bool forgetFreeSpace
Definition: logtape.c:197

◆ LogicalTapeTell()

void LogicalTapeTell ( LogicalTapeSet lts,
int  tapenum,
long *  blocknum,
int *  offset 
)

Definition at line 1066 of file logtape.c.

References Assert, LogicalTape::buffer_size, LogicalTape::curBlockNumber, LogicalTape::offsetBlockNumber, LogicalTape::pos, and LogicalTapeSet::tapes.

Referenced by tuplesort_markpos().

1068 {
1069  LogicalTape *lt;
1070 
1071  Assert(tapenum >= 0 && tapenum < lts->nTapes);
1072  lt = &lts->tapes[tapenum];
1073  Assert(lt->offsetBlockNumber == 0L);
1074 
1075  /* With a larger buffer, 'pos' wouldn't be the same as offset within page */
1076  Assert(lt->buffer_size == BLCKSZ);
1077 
1078  *blocknum = lt->curBlockNumber;
1079  *offset = lt->pos;
1080 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
long offsetBlockNumber
Definition: logtape.c:148
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
int buffer_size
Definition: logtape.c:154

◆ LogicalTapeWrite()

void LogicalTapeWrite ( LogicalTapeSet lts,
int  tapenum,
void *  ptr,
size_t  size 
)

Definition at line 625 of file logtape.c.

References Assert, LogicalTape::buffer, LogicalTape::buffer_size, LogicalTape::curBlockNumber, LogicalTape::dirty, elog, ERROR, LogicalTape::firstBlockNumber, ltsGetFreeBlock(), ltsWriteBlock(), LogicalTape::nbytes, LogicalTape::offsetBlockNumber, palloc(), LogicalTape::pos, TapeBlockGetTrailer, TapeBlockPayloadSize, LogicalTapeSet::tapes, and LogicalTape::writing.

Referenced by markrunend(), writetup_cluster(), writetup_datum(), writetup_heap(), and writetup_index().

627 {
628  LogicalTape *lt;
629  size_t nthistime;
630 
631  Assert(tapenum >= 0 && tapenum < lts->nTapes);
632  lt = &lts->tapes[tapenum];
633  Assert(lt->writing);
634  Assert(lt->offsetBlockNumber == 0L);
635 
636  /* Allocate data buffer and first block on first write */
637  if (lt->buffer == NULL)
638  {
639  lt->buffer = (char *) palloc(BLCKSZ);
640  lt->buffer_size = BLCKSZ;
641  }
642  if (lt->curBlockNumber == -1)
643  {
644  Assert(lt->firstBlockNumber == -1);
645  Assert(lt->pos == 0);
646 
647  lt->curBlockNumber = ltsGetFreeBlock(lts);
649 
650  TapeBlockGetTrailer(lt->buffer)->prev = -1L;
651  }
652 
653  Assert(lt->buffer_size == BLCKSZ);
654  while (size > 0)
655  {
656  if (lt->pos >= TapeBlockPayloadSize)
657  {
658  /* Buffer full, dump it out */
659  long nextBlockNumber;
660 
661  if (!lt->dirty)
662  {
663  /* Hmm, went directly from reading to writing? */
664  elog(ERROR, "invalid logtape state: should be dirty");
665  }
666 
667  /*
668  * First allocate the next block, so that we can store it in the
669  * 'next' pointer of this block.
670  */
671  nextBlockNumber = ltsGetFreeBlock(lts);
672 
673  /* set the next-pointer and dump the current block. */
674  TapeBlockGetTrailer(lt->buffer)->next = nextBlockNumber;
675  ltsWriteBlock(lts, lt->curBlockNumber, (void *) lt->buffer);
676 
677  /* initialize the prev-pointer of the next block */
678  TapeBlockGetTrailer(lt->buffer)->prev = lt->curBlockNumber;
679  lt->curBlockNumber = nextBlockNumber;
680  lt->pos = 0;
681  lt->nbytes = 0;
682  }
683 
684  nthistime = TapeBlockPayloadSize - lt->pos;
685  if (nthistime > size)
686  nthistime = size;
687  Assert(nthistime > 0);
688 
689  memcpy(lt->buffer + lt->pos, ptr, nthistime);
690 
691  lt->dirty = true;
692  lt->pos += nthistime;
693  if (lt->nbytes < lt->pos)
694  lt->nbytes = lt->pos;
695  ptr = (void *) ((char *) ptr + nthistime);
696  size -= nthistime;
697  }
698 }
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
#define TapeBlockPayloadSize
Definition: logtape.c:106
long offsetBlockNumber
Definition: logtape.c:148
static long ltsGetFreeBlock(LogicalTapeSet *lts)
Definition: logtape.c:345
bool writing
Definition: logtape.c:130
bool dirty
Definition: logtape.c:132
#define ERROR
Definition: elog.h:43
int nbytes
Definition: logtape.c:157
long firstBlockNumber
Definition: logtape.c:145
long curBlockNumber
Definition: logtape.c:146
#define Assert(condition)
Definition: c.h:699
char * buffer
Definition: logtape.c:153
void * palloc(Size size)
Definition: mcxt.c:924
#define elog
Definition: elog.h:219
int buffer_size
Definition: logtape.c:154
static void ltsWriteBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:222
#define TapeBlockGetTrailer(buf)
Definition: logtape.c:107

◆ ltsConcatWorkerTapes()

static void ltsConcatWorkerTapes ( LogicalTapeSet lts,
TapeShare shared,
SharedFileSet fileset 
)
static

Definition at line 409 of file logtape.c.

References Assert, BufFileAppend(), BufFileOpenShared(), BufFileSize(), ereport, errcode_for_file_access(), errmsg(), ERROR, filename, TapeShare::firstblocknumber, LogicalTape::firstBlockNumber, i, LogicalTape::max_size, MaxAllocSize, MAXPGPATH, Min, LogicalTapeSet::nBlocksAllocated, LogicalTapeSet::nBlocksWritten, LogicalTapeSet::nHoleBlocks, LogicalTapeSet::nTapes, LogicalTape::offsetBlockNumber, LogicalTapeSet::pfile, pg_itoa(), and LogicalTapeSet::tapes.

Referenced by LogicalTapeSetCreate().

411 {
412  LogicalTape *lt = NULL;
413  long tapeblocks = 0L;
414  long nphysicalblocks = 0L;
415  int i;
416 
417  /* Should have at least one worker tape, plus leader's tape */
418  Assert(lts->nTapes >= 2);
419 
420  /*
421  * Build concatenated view of all BufFiles, remembering the block number
422  * where each source file begins. No changes are needed for leader/last
423  * tape.
424  */
425  for (i = 0; i < lts->nTapes - 1; i++)
426  {
427  char filename[MAXPGPATH];
428  BufFile *file;
429  off_t filesize;
430 
431  lt = &lts->tapes[i];
432 
433  pg_itoa(i, filename);
434  file = BufFileOpenShared(fileset, filename);
435  filesize = BufFileSize(file);
436  if (filesize < 0)
437  ereport(ERROR,
439  errmsg("could not determine size of temporary file \"%s\"", filename)));
440 
441  /*
442  * Stash first BufFile, and concatenate subsequent BufFiles to that.
443  * Store block offset into each tape as we go.
444  */
445  lt->firstBlockNumber = shared[i].firstblocknumber;
446  if (i == 0)
447  {
448  lts->pfile = file;
449  lt->offsetBlockNumber = 0L;
450  }
451  else
452  {
453  lt->offsetBlockNumber = BufFileAppend(lts->pfile, file);
454  }
455  /* Don't allocate more for read buffer than could possibly help */
456  lt->max_size = Min(MaxAllocSize, filesize);
457  tapeblocks = filesize / BLCKSZ;
458  nphysicalblocks += tapeblocks;
459  }
460 
461  /*
462  * Set # of allocated blocks, as well as # blocks written. Use extent of
463  * new BufFile space (from 0 to end of last worker's tape space) for this.
464  * Allocated/written blocks should include space used by holes left
465  * between concatenated BufFiles.
466  */
467  lts->nBlocksAllocated = lt->offsetBlockNumber + tapeblocks;
468  lts->nBlocksWritten = lts->nBlocksAllocated;
469 
470  /*
471  * Compute number of hole blocks so that we can later work backwards, and
472  * instrument number of physical blocks. We don't simply use physical
473  * blocks directly for instrumentation because this would break if we ever
474  * subsequently wrote to worker tape.
475  *
476  * Working backwards like this keeps our options open. If shared BufFiles
477  * ever support being written to post-export, logtape.c can automatically
478  * take advantage of that. We'd then support writing to the leader tape
479  * while recycling space from worker tapes, because the leader tape has a
480  * zero offset (write routines won't need to have extra logic to apply an
481  * offset).
482  *
483  * The only thing that currently prevents writing to the leader tape from
484  * working is the fact that BufFiles opened using BufFileOpenShared() are
485  * read-only by definition, but that could be changed if it seemed
486  * worthwhile. For now, writing to the leader tape will raise a "Bad file
487  * descriptor" error, so tuplesort must avoid writing to the leader tape
488  * altogether.
489  */
490  lts->nHoleBlocks = lts->nBlocksAllocated - nphysicalblocks;
491 }
int max_size
Definition: logtape.c:155
LogicalTape tapes[FLEXIBLE_ARRAY_MEMBER]
Definition: logtape.c:205
long offsetBlockNumber
Definition: logtape.c:148
long nBlocksWritten
Definition: logtape.c:181
BufFile * BufFileOpenShared(SharedFileSet *fileset, const char *name)
Definition: buffile.c:278
#define Min(x, y)
Definition: c.h:857
BufFile * pfile
Definition: logtape.c:168
long firstblocknumber
Definition: logtape.h:50
#define ERROR
Definition: elog.h:43
#define MAXPGPATH
int errcode_for_file_access(void)
Definition: elog.c:598
long nHoleBlocks
Definition: logtape.c:182
#define ereport(elevel, rest)
Definition: elog.h:122
void pg_itoa(int16 i, char *a)
Definition: numutils.c:120
#define MaxAllocSize
Definition: memutils.h:40
long firstBlockNumber
Definition: logtape.c:145
#define Assert(condition)
Definition: c.h:699
static char * filename
Definition: pg_dumpall.c:87
int errmsg(const char *fmt,...)
Definition: elog.c:797
int i
long BufFileAppend(BufFile *target, BufFile *source)
Definition: buffile.c:845
long nBlocksAllocated
Definition: logtape.c:180
off_t BufFileSize(BufFile *file)
Definition: buffile.c:811

◆ ltsGetFreeBlock()

static long ltsGetFreeBlock ( LogicalTapeSet lts)
static

Definition at line 345 of file logtape.c.

References LogicalTapeSet::blocksSorted, LogicalTapeSet::freeBlocks, freeBlocks_cmp(), LogicalTapeSet::nBlocksAllocated, LogicalTapeSet::nFreeBlocks, and qsort.

Referenced by LogicalTapeWrite().

346 {
347  /*
348  * If there are multiple free blocks, we select the one appearing last in
349  * freeBlocks[] (after sorting the array if needed). If there are none,
350  * assign the next block at the end of the file.
351  */
352  if (lts->nFreeBlocks > 0)
353  {
354  if (!lts->blocksSorted)
355  {
356  qsort((void *) lts->freeBlocks, lts->nFreeBlocks,
357  sizeof(long), freeBlocks_cmp);
358  lts->blocksSorted = true;
359  }
360  return lts->freeBlocks[--lts->nFreeBlocks];
361  }
362  else
363  return lts->nBlocksAllocated++;
364 }
int nFreeBlocks
Definition: logtape.c:200
long * freeBlocks
Definition: logtape.c:199
static int freeBlocks_cmp(const void *a, const void *b)
Definition: logtape.c:328
#define qsort(a, b, c, d)
Definition: port.h:421
bool blocksSorted
Definition: logtape.c:198
long nBlocksAllocated
Definition: logtape.c:180

◆ ltsReadBlock()

static void ltsReadBlock ( LogicalTapeSet lts,
long  blocknum,
void *  buffer 
)
static

Definition at line 270 of file logtape.c.

References BufFileRead(), BufFileSeekBlock(), ereport, errcode_for_file_access(), errmsg(), ERROR, and LogicalTapeSet::pfile.

Referenced by LogicalTapeBackspace(), LogicalTapeFreeze(), LogicalTapeSeek(), and ltsReadFillBuffer().

271 {
272  if (BufFileSeekBlock(lts->pfile, blocknum) != 0 ||
273  BufFileRead(lts->pfile, buffer, BLCKSZ) != BLCKSZ)
274  ereport(ERROR,
276  errmsg("could not read block %ld of temporary file: %m",
277  blocknum)));
278 }
BufFile * pfile
Definition: logtape.c:168
#define ERROR
Definition: elog.h:43
int errcode_for_file_access(void)
Definition: elog.c:598
#define ereport(elevel, rest)
Definition: elog.h:122
int BufFileSeekBlock(BufFile *file, long blknum)
Definition: buffile.c:778
WalTimeSample buffer[LAG_TRACKER_BUFFER_SIZE]
Definition: walsender.c:215
int errmsg(const char *fmt,...)
Definition: elog.c:797
size_t BufFileRead(BufFile *file, void *ptr, size_t size)
Definition: buffile.c:554

◆ ltsReadFillBuffer()

static bool ltsReadFillBuffer ( LogicalTapeSet lts,
LogicalTape lt 
)
static

Definition at line 286 of file logtape.c.

References LogicalTape::buffer, LogicalTape::buffer_size, LogicalTape::curBlockNumber, LogicalTape::frozen, ltsReadBlock(), ltsReleaseBlock(), LogicalTape::nbytes, LogicalTape::nextBlockNumber, LogicalTape::offsetBlockNumber, LogicalTape::pos, TapeBlockGetNBytes, TapeBlockGetTrailer, and TapeBlockIsLast.

Referenced by LogicalTapeRead(), and LogicalTapeRewindForRead().

287 {
288  lt->pos = 0;
289  lt->nbytes = 0;
290 
291  do
292  {
293  char *thisbuf = lt->buffer + lt->nbytes;
294  long datablocknum = lt->nextBlockNumber;
295 
296  /* Fetch next block number */
297  if (datablocknum == -1L)
298  break; /* EOF */
299  /* Apply worker offset, needed for leader tapesets */
300  datablocknum += lt->offsetBlockNumber;
301 
302  /* Read the block */
303  ltsReadBlock(lts, datablocknum, (void *) thisbuf);
304  if (!lt->frozen)
305  ltsReleaseBlock(lts, datablocknum);
307 
308  lt->nbytes += TapeBlockGetNBytes(thisbuf);
309  if (TapeBlockIsLast(thisbuf))
310  {
311  lt->nextBlockNumber = -1L;
312  /* EOF */
313  break;
314  }
315  else
316  lt->nextBlockNumber = TapeBlockGetTrailer(thisbuf)->next;
317 
318  /* Advance to next block, if we have buffer space left */
319  } while (lt->buffer_size - lt->nbytes > BLCKSZ);
320 
321  return (lt->nbytes > 0);
322 }
#define TapeBlockIsLast(buf)
Definition: logtape.c:110
long offsetBlockNumber
Definition: logtape.c:148
static void ltsReleaseBlock(LogicalTapeSet *lts, long blocknum)
Definition: logtape.c:370
bool frozen
Definition: logtape.c:131
long nextBlockNumber
Definition: logtape.c:147
int nbytes
Definition: logtape.c:157
long curBlockNumber
Definition: logtape.c:146
#define TapeBlockGetNBytes(buf)
Definition: logtape.c:111
char * buffer
Definition: logtape.c:153
int buffer_size
Definition: logtape.c:154
#define TapeBlockGetTrailer(buf)
Definition: logtape.c:107
static void ltsReadBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:270

◆ ltsReleaseBlock()

static void ltsReleaseBlock ( LogicalTapeSet lts,
long  blocknum 
)
static

Definition at line 370 of file logtape.c.

References LogicalTapeSet::blocksSorted, LogicalTapeSet::forgetFreeSpace, LogicalTapeSet::freeBlocks, LogicalTapeSet::freeBlocksLen, LogicalTapeSet::nFreeBlocks, and repalloc().

Referenced by ltsReadFillBuffer().

371 {
372  int ndx;
373 
374  /*
375  * Do nothing if we're no longer interested in remembering free space.
376  */
377  if (lts->forgetFreeSpace)
378  return;
379 
380  /*
381  * Enlarge freeBlocks array if full.
382  */
383  if (lts->nFreeBlocks >= lts->freeBlocksLen)
384  {
385  lts->freeBlocksLen *= 2;
386  lts->freeBlocks = (long *) repalloc(lts->freeBlocks,
387  lts->freeBlocksLen * sizeof(long));
388  }
389 
390  /*
391  * Add blocknum to array, and mark the array unsorted if it's no longer in
392  * decreasing order.
393  */
394  ndx = lts->nFreeBlocks++;
395  lts->freeBlocks[ndx] = blocknum;
396  if (ndx > 0 && lts->freeBlocks[ndx - 1] < blocknum)
397  lts->blocksSorted = false;
398 }
int nFreeBlocks
Definition: logtape.c:200
int freeBlocksLen
Definition: logtape.c:201
long * freeBlocks
Definition: logtape.c:199
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:1044
bool forgetFreeSpace
Definition: logtape.c:197
bool blocksSorted
Definition: logtape.c:198

◆ ltsWriteBlock()

static void ltsWriteBlock ( LogicalTapeSet lts,
long  blocknum,
void *  buffer 
)
static

Definition at line 222 of file logtape.c.

References BufFileSeekBlock(), BufFileWrite(), ereport, errcode_for_file_access(), errmsg(), ERROR, MemSet, LogicalTapeSet::nBlocksWritten, and LogicalTapeSet::pfile.

Referenced by LogicalTapeFreeze(), LogicalTapeRewindForRead(), and LogicalTapeWrite().

223 {
224  /*
225  * BufFile does not support "holes", so if we're about to write a block
226  * that's past the current end of file, fill the space between the current
227  * end of file and the target block with zeros.
228  *
229  * This should happen rarely, otherwise you are not writing very
230  * sequentially. In current use, this only happens when the sort ends
231  * writing a run, and switches to another tape. The last block of the
232  * previous tape isn't flushed to disk until the end of the sort, so you
233  * get one-block hole, where the last block of the previous tape will
234  * later go.
235  *
236  * Note that BufFile concatenation can leave "holes" in BufFile between
237  * worker-owned block ranges. These are tracked for reporting purposes
238  * only. We never read from nor write to these hole blocks, and so they
239  * are not considered here.
240  */
241  while (blocknum > lts->nBlocksWritten)
242  {
243  char zerobuf[BLCKSZ];
244 
245  MemSet(zerobuf, 0, sizeof(zerobuf));
246 
247  ltsWriteBlock(lts, lts->nBlocksWritten, zerobuf);
248  }
249 
250  /* Write the requested block */
251  if (BufFileSeekBlock(lts->pfile, blocknum) != 0 ||
252  BufFileWrite(lts->pfile, buffer, BLCKSZ) != BLCKSZ)
253  ereport(ERROR,
255  errmsg("could not write block %ld of temporary file: %m",
256  blocknum)));
257 
258  /* Update nBlocksWritten, if we extended the file */
259  if (blocknum == lts->nBlocksWritten)
260  lts->nBlocksWritten++;
261 }
long nBlocksWritten
Definition: logtape.c:181
BufFile * pfile
Definition: logtape.c:168
#define MemSet(start, val, len)
Definition: c.h:908
#define ERROR
Definition: elog.h:43
int errcode_for_file_access(void)
Definition: elog.c:598
#define ereport(elevel, rest)
Definition: elog.h:122
int BufFileSeekBlock(BufFile *file, long blknum)
Definition: buffile.c:778
WalTimeSample buffer[LAG_TRACKER_BUFFER_SIZE]
Definition: walsender.c:215
int errmsg(const char *fmt,...)
Definition: elog.c:797
size_t BufFileWrite(BufFile *file, void *ptr, size_t size)
Definition: buffile.c:601
static void ltsWriteBlock(LogicalTapeSet *lts, long blocknum, void *buffer)
Definition: logtape.c:222