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Commit4c9deeb

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Move mdwriteback() to better place
The previous order in the file didn't make sense and matched neitherthe header file nor the smgr API.Discussion:https://www.postgresql.org/message-id/flat/22fed8ba-01c3-2008-a256-4ea912d68fab%40enterprisedb.com
1 parent0b8ace8 commit4c9deeb

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1 file changed

+57
-57
lines changed
  • src/backend/storage/smgr

1 file changed

+57
-57
lines changed

‎src/backend/storage/smgr/md.c

Lines changed: 57 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -733,63 +733,6 @@ mdprefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum)
733733
return true;
734734
}
735735

736-
/*
737-
* mdwriteback() -- Tell the kernel to write pages back to storage.
738-
*
739-
* This accepts a range of blocks because flushing several pages at once is
740-
* considerably more efficient than doing so individually.
741-
*/
742-
void
743-
mdwriteback(SMgrRelationreln,ForkNumberforknum,
744-
BlockNumberblocknum,BlockNumbernblocks)
745-
{
746-
Assert((io_direct_flags&IO_DIRECT_DATA)==0);
747-
748-
/*
749-
* Issue flush requests in as few requests as possible; have to split at
750-
* segment boundaries though, since those are actually separate files.
751-
*/
752-
while (nblocks>0)
753-
{
754-
BlockNumbernflush=nblocks;
755-
off_tseekpos;
756-
MdfdVec*v;
757-
intsegnum_start,
758-
segnum_end;
759-
760-
v=_mdfd_getseg(reln,forknum,blocknum, true/* not used */ ,
761-
EXTENSION_DONT_OPEN);
762-
763-
/*
764-
* We might be flushing buffers of already removed relations, that's
765-
* ok, just ignore that case. If the segment file wasn't open already
766-
* (ie from a recent mdwrite()), then we don't want to re-open it, to
767-
* avoid a race with PROCSIGNAL_BARRIER_SMGRRELEASE that might leave
768-
* us with a descriptor to a file that is about to be unlinked.
769-
*/
770-
if (!v)
771-
return;
772-
773-
/* compute offset inside the current segment */
774-
segnum_start=blocknum /RELSEG_SIZE;
775-
776-
/* compute number of desired writes within the current segment */
777-
segnum_end= (blocknum+nblocks-1) /RELSEG_SIZE;
778-
if (segnum_start!=segnum_end)
779-
nflush=RELSEG_SIZE- (blocknum % ((BlockNumber)RELSEG_SIZE));
780-
781-
Assert(nflush >=1);
782-
Assert(nflush <=nblocks);
783-
784-
seekpos= (off_t)BLCKSZ* (blocknum % ((BlockNumber)RELSEG_SIZE));
785-
786-
FileWriteback(v->mdfd_vfd,seekpos, (off_t)BLCKSZ*nflush,WAIT_EVENT_DATA_FILE_FLUSH);
787-
788-
nblocks-=nflush;
789-
blocknum+=nflush;
790-
}
791-
}
792-
793736
/*
794737
* mdread() -- Read the specified block from a relation.
795738
*/
@@ -923,6 +866,63 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
923866
register_dirty_segment(reln,forknum,v);
924867
}
925868

869+
/*
870+
* mdwriteback() -- Tell the kernel to write pages back to storage.
871+
*
872+
* This accepts a range of blocks because flushing several pages at once is
873+
* considerably more efficient than doing so individually.
874+
*/
875+
void
876+
mdwriteback(SMgrRelationreln,ForkNumberforknum,
877+
BlockNumberblocknum,BlockNumbernblocks)
878+
{
879+
Assert((io_direct_flags&IO_DIRECT_DATA)==0);
880+
881+
/*
882+
* Issue flush requests in as few requests as possible; have to split at
883+
* segment boundaries though, since those are actually separate files.
884+
*/
885+
while (nblocks>0)
886+
{
887+
BlockNumbernflush=nblocks;
888+
off_tseekpos;
889+
MdfdVec*v;
890+
intsegnum_start,
891+
segnum_end;
892+
893+
v=_mdfd_getseg(reln,forknum,blocknum, true/* not used */ ,
894+
EXTENSION_DONT_OPEN);
895+
896+
/*
897+
* We might be flushing buffers of already removed relations, that's
898+
* ok, just ignore that case. If the segment file wasn't open already
899+
* (ie from a recent mdwrite()), then we don't want to re-open it, to
900+
* avoid a race with PROCSIGNAL_BARRIER_SMGRRELEASE that might leave
901+
* us with a descriptor to a file that is about to be unlinked.
902+
*/
903+
if (!v)
904+
return;
905+
906+
/* compute offset inside the current segment */
907+
segnum_start=blocknum /RELSEG_SIZE;
908+
909+
/* compute number of desired writes within the current segment */
910+
segnum_end= (blocknum+nblocks-1) /RELSEG_SIZE;
911+
if (segnum_start!=segnum_end)
912+
nflush=RELSEG_SIZE- (blocknum % ((BlockNumber)RELSEG_SIZE));
913+
914+
Assert(nflush >=1);
915+
Assert(nflush <=nblocks);
916+
917+
seekpos= (off_t)BLCKSZ* (blocknum % ((BlockNumber)RELSEG_SIZE));
918+
919+
FileWriteback(v->mdfd_vfd,seekpos, (off_t)BLCKSZ*nflush,WAIT_EVENT_DATA_FILE_FLUSH);
920+
921+
nblocks-=nflush;
922+
blocknum+=nflush;
923+
}
924+
}
925+
926926
/*
927927
* mdnblocks() -- Get the number of blocks stored in a relation.
928928
*

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