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Move mdwriteback() to better place

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The previous order in the file didn't make sense and matched neither
the header file nor the smgr API.

Discussion: https://www.postgresql.org/message-id/flat/22fed8ba-01c3-2008-a256-4ea912d68fab%40enterprisedb.com
This commit is contained in:
Peter Eisentraut
2023-05-19 13:42:06 +02:00
parent 0b8ace8d77
commit 4c9deebd37
1 changed files with 57 additions and 57 deletions
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114
src/backend/storage/smgr/md.c
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@ -733,63 +733,6 @@ mdprefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum)
return true; return true;
} }
/*
* mdwriteback() -- Tell the kernel to write pages back to storage.
*
* This accepts a range of blocks because flushing several pages at once is
* considerably more efficient than doing so individually.
*/
void
mdwriteback(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, BlockNumber nblocks)
{
Assert((io_direct_flags & IO_DIRECT_DATA) == 0);
/*
* Issue flush requests in as few requests as possible; have to split at
* segment boundaries though, since those are actually separate files.
*/
while (nblocks > 0)
{
BlockNumber nflush = nblocks;
off_t seekpos;
MdfdVec *v;
int segnum_start,
segnum_end;
v = _mdfd_getseg(reln, forknum, blocknum, true /* not used */ ,
EXTENSION_DONT_OPEN);
/*
* We might be flushing buffers of already removed relations, that's
* ok, just ignore that case. If the segment file wasn't open already
* (ie from a recent mdwrite()), then we don't want to re-open it, to
* avoid a race with PROCSIGNAL_BARRIER_SMGRRELEASE that might leave
* us with a descriptor to a file that is about to be unlinked.
*/
if (!v)
return;
/* compute offset inside the current segment */
segnum_start = blocknum / RELSEG_SIZE;
/* compute number of desired writes within the current segment */
segnum_end = (blocknum + nblocks - 1) / RELSEG_SIZE;
if (segnum_start != segnum_end)
nflush = RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE));
Assert(nflush >= 1);
Assert(nflush <= nblocks);
seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
FileWriteback(v->mdfd_vfd, seekpos, (off_t) BLCKSZ * nflush, WAIT_EVENT_DATA_FILE_FLUSH);
nblocks -= nflush;
blocknum += nflush;
}
}
/* /*
* mdread() -- Read the specified block from a relation. * mdread() -- Read the specified block from a relation.
*/ */
@ -923,6 +866,63 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
register_dirty_segment(reln, forknum, v); register_dirty_segment(reln, forknum, v);
} }
/*
* mdwriteback() -- Tell the kernel to write pages back to storage.
*
* This accepts a range of blocks because flushing several pages at once is
* considerably more efficient than doing so individually.
*/
void
mdwriteback(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, BlockNumber nblocks)
{
Assert((io_direct_flags & IO_DIRECT_DATA) == 0);
/*
* Issue flush requests in as few requests as possible; have to split at
* segment boundaries though, since those are actually separate files.
*/
while (nblocks > 0)
{
BlockNumber nflush = nblocks;
off_t seekpos;
MdfdVec *v;
int segnum_start,
segnum_end;
v = _mdfd_getseg(reln, forknum, blocknum, true /* not used */ ,
EXTENSION_DONT_OPEN);
/*
* We might be flushing buffers of already removed relations, that's
* ok, just ignore that case. If the segment file wasn't open already
* (ie from a recent mdwrite()), then we don't want to re-open it, to
* avoid a race with PROCSIGNAL_BARRIER_SMGRRELEASE that might leave
* us with a descriptor to a file that is about to be unlinked.
*/
if (!v)
return;
/* compute offset inside the current segment */
segnum_start = blocknum / RELSEG_SIZE;
/* compute number of desired writes within the current segment */
segnum_end = (blocknum + nblocks - 1) / RELSEG_SIZE;
if (segnum_start != segnum_end)
nflush = RELSEG_SIZE - (blocknum % ((BlockNumber) RELSEG_SIZE));
Assert(nflush >= 1);
Assert(nflush <= nblocks);
seekpos = (off_t) BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE));
FileWriteback(v->mdfd_vfd, seekpos, (off_t) BLCKSZ * nflush, WAIT_EVENT_DATA_FILE_FLUSH);
nblocks -= nflush;
blocknum += nflush;
}
}
/* /*
* mdnblocks() -- Get the number of blocks stored in a relation. * mdnblocks() -- Get the number of blocks stored in a relation.
* *