/*
* Update the upper levels of the free space map all the way up to the root
* to make sure we don't lose track of new blocks we just inserted. This is
* intended to be used after adding many new blocks to the relation; we judge
* it not worth updating the upper levels of the tree every time data for
* a single page changes, but for a bulk-extend it's worth it.
*/
void
UpdateFreeSpaceMap(Relation rel, BlockNumber startBlkNum,
BlockNumber endBlkNum, Size freespace)
{
int new_cat = fsm_space_avail_to_cat(freespace);
FSMAddress addr;
uint16 slot;
BlockNumber blockNum;
BlockNumber lastBlkOnPage;
blockNum = startBlkNum;
while (blockNum <= endBlkNum)
{
/*
* Find FSM address for this block; update tree all the way to the
* root.
*/
addr = fsm_get_location(blockNum, &slot);
fsm_update_recursive(rel, addr, new_cat);
/*
* Get the last block number on this FSM page. If that's greater
* than or equal to our endBlkNum, we're done. Otherwise, advance
* to the first block on the next page.
*/
lastBlkOnPage = fsm_get_lastblckno(rel, addr);
if (lastBlkOnPage >= endBlkNum)
break;
blockNum = lastBlkOnPage + 1;
}
}
/*
* XLogRecordPageWithFreeSpace - like RecordPageWithFreeSpace, for use in
* WAL replay
*/
void
XLogRecordPageWithFreeSpace(RelFileNode rnode, BlockNumber heapBlk,
Size spaceAvail)
{
int new_cat = fsm_space_avail_to_cat(spaceAvail);
FSMAddress addr;
uint16 slot;
BlockNumber blkno;
Buffer buf;
Page page;
/* Get the location of the FSM byte representing the heap block */
addr = fsm_get_location(heapBlk, &slot);
blkno = fsm_logical_to_physical(addr);
/* If the page doesn't exist already, extend */
buf = XLogReadBufferExtended(rnode, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);
if (PageIsNew(page))
PageInit(page, BLCKSZ, 0);
if (fsm_set_avail(page, slot, new_cat))
MarkBufferDirtyHint(buf, false);
UnlockReleaseBuffer(buf);
}
/*
* FreeSpaceMapTruncateRel - adjust for truncation of a relation.
*
* The caller must hold AccessExclusiveLock on the relation, to ensure that
* other backends receive the smgr invalidation event that this function sends
* before they access the FSM again.
*
* nblocks is the new___ size of the heap.
*/
void
FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks)
{
BlockNumber new_nfsmblocks;
FSMAddress first_removed_address;
uint16 first_removed_slot;
Buffer buf;
RelationOpenSmgr(rel);
/*
* If no FSM has been created yet for this relation, there's nothing to
* truncate.
*/
if (!smgrexists(rel->rd_smgr, FSM_FORKNUM))
return;
/* Get the location in the FSM of the first removed heap block */
first_removed_address = fsm_get_location(nblocks, &first_removed_slot);
/*
* Zero out the tail of the last remaining FSM page. If the slot
* representing the first removed heap block is at a page boundary, as the
* first slot on the FSM page that first_removed_address points to, we can
* just truncate that page altogether.
*/
if (first_removed_slot > 0)
{
buf = fsm_readbuf(rel, first_removed_address, false);
if (!BufferIsValid(buf))
return; /* nothing to do; the FSM was already smaller */
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
fsm_truncate_avail(BufferGetPage(buf), first_removed_slot);
MarkBufferDirtyHint(buf, false);
UnlockReleaseBuffer(buf);
new_nfsmblocks = fsm_logical_to_physical(first_removed_address) + 1;
}
else
{
new_nfsmblocks = fsm_logical_to_physical(first_removed_address);
if (smgrnblocks(rel->rd_smgr, FSM_FORKNUM) <= new_nfsmblocks)
return; /* nothing to do; the FSM was already smaller */
}
/* Truncate the unused FSM pages, and send smgr inval message */
smgrtruncate(rel->rd_smgr, FSM_FORKNUM, new_nfsmblocks);
/*
* We might as well update the local smgr_fsm_nblocks setting.
* smgrtruncate sent an smgr cache inval message, which will cause other
* backends to invalidate their copy of smgr_fsm_nblocks, and this one too
* at the next command boundary. But this ensures it isn't outright wrong
* until then.
*/
if (rel->rd_smgr)
rel->rd_smgr->smgr_fsm_nblocks = new_nfsmblocks;
}
/*
* RecordPageWithFreeSpace - update info about a page.
*
* Note that if the new___ spaceAvail value is higher than the old value stored
* in the FSM, the space might not become visible to searchers until the next
* FreeSpaceMapVacuum call, which updates the upper level pages.
*/
void
RecordPageWithFreeSpace(Relation rel, BlockNumber heapBlk, Size spaceAvail)
{
int new_cat = fsm_space_avail_to_cat(spaceAvail);
FSMAddress addr;
uint16 slot;
/* Get the location of the FSM byte representing the heap block */
addr = fsm_get_location(heapBlk, &slot);
fsm_set_and_search(rel, addr, slot, new_cat, 0);
}
/*
* XLogRecordPageWithFreeSpace - like RecordPageWithFreeSpace, for use in
* WAL replay
*/
void
XLogRecordPageWithFreeSpace(RelFileNode rnode, BlockNumber heapBlk,
Size spaceAvail)
{
int new_cat = fsm_space_avail_to_cat(spaceAvail);
FSMAddress addr;
uint16 slot;
BlockNumber blkno;
Buffer buf;
Page page;
bool write_to_fsm;
/* This is meant to mirror the logic in fsm_allow_writes() */
if (heapBlk >= HEAP_FSM_CREATION_THRESHOLD)
write_to_fsm = true;
else
{
/* Open the relation at smgr level */
SMgrRelation smgr = smgropen(rnode, InvalidBackendId);
if (smgrexists(smgr, FSM_FORKNUM))
write_to_fsm = true;
else
{
BlockNumber heap_nblocks = smgrnblocks(smgr, MAIN_FORKNUM);
if (heap_nblocks > HEAP_FSM_CREATION_THRESHOLD)
write_to_fsm = true;
else
write_to_fsm = false;
}
}
if (!write_to_fsm)
return;
/* Get the location of the FSM byte representing the heap block */
addr = fsm_get_location(heapBlk, &slot);
blkno = fsm_logical_to_physical(addr);
/* If the page doesn't exist already, extend */
buf = XLogReadBufferExtended(rnode, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
page = BufferGetPage(buf);
if (PageIsNew(page))
PageInit(page, BLCKSZ, 0);
if (fsm_set_avail(page, slot, new_cat))
MarkBufferDirtyHint(buf, false);
UnlockReleaseBuffer(buf);
}
/*
* RecordAndGetPageWithFreeSpace - update info about a page and try again.
*
* We provide this combo form to save some locking overhead, compared to
* separate RecordPageWithFreeSpace + GetPageWithFreeSpace calls. There's
* also some effort to return a page close to the old page; if there's a
* page with enough free space on the same FSM page where the old one page
* is located, it is preferred.
*
* For very small heap relations that don't have a FSM, we update the local
* map to indicate we have tried a page, and return the next page to try.
*/
BlockNumber
RecordAndGetPageWithFreeSpace(Relation rel, BlockNumber oldPage,
Size oldSpaceAvail, Size spaceNeeded)
{
int old_cat;
int search_cat;
FSMAddress addr;
uint16 slot;
int search_slot;
BlockNumber nblocks = InvalidBlockNumber;
/* First try the local map, if it exists. */
if (FSM_LOCAL_MAP_EXISTS)
{
Assert((rel->rd_rel->relkind == RELKIND_RELATION ||
rel->rd_rel->relkind == RELKIND_TOASTVALUE) &&
fsm_local_map.map[oldPage] == FSM_LOCAL_AVAIL);
fsm_local_map.map[oldPage] = FSM_LOCAL_NOT_AVAIL;
return fsm_local_search();
}
if (!fsm_allow_writes(rel, oldPage, InvalidBlockNumber, &nblocks))
{
/*
* If we have neither a local map nor a FSM, we probably just tried
* the target block in the smgr relation entry and failed, so we'll
* need to create the local map.
*/
fsm_local_set(rel, nblocks);
return fsm_local_search();
}
/* Normal FSM logic follows */
old_cat = fsm_space_avail_to_cat(oldSpaceAvail);
search_cat = fsm_space_needed_to_cat(spaceNeeded);
/* Get the location of the FSM byte representing the heap block */
addr = fsm_get_location(oldPage, &slot);
search_slot = fsm_set_and_search(rel, addr, slot, old_cat, search_cat);
/*
* If fsm_set_and_search found a suitable new block, return that.
* Otherwise, search as usual.
*/
if (search_slot != -1)
return fsm_get_heap_blk(addr, search_slot);
else
return fsm_search(rel, search_cat);
}
/*
* GetRecordedFreePage - return the amount of free space on a particular page,
* according to the FSM.
*/
Size
GetRecordedFreeSpace(Relation rel, BlockNumber heapBlk)
{
FSMAddress addr;
uint16 slot;
Buffer buf;
uint8 cat;
/* Get the location of the FSM byte representing the heap block */
addr = fsm_get_location(heapBlk, &slot);
buf = fsm_readbuf(rel, addr, false);
if (!BufferIsValid(buf))
return 0;
cat = fsm_get_avail(BufferGetPage(buf), slot);
ReleaseBuffer(buf);
return fsm_space_cat_to_avail(cat);
}
/*
* RecordPageWithFreeSpace - update info about a page.
*
* Note that if the new spaceAvail value is higher than the old value stored
* in the FSM, the space might not become visible to searchers until the next
* FreeSpaceMapVacuum call, which updates the upper level pages.
*
* Callers have no need for a local map.
*/
void
RecordPageWithFreeSpace(Relation rel, BlockNumber heapBlk,
Size spaceAvail, BlockNumber nblocks)
{
int new_cat;
FSMAddress addr;
uint16 slot;
BlockNumber dummy;
if (!fsm_allow_writes(rel, heapBlk, nblocks, &dummy))
/* No FSM to update and no local map either */
return;
/* Get the location of the FSM byte representing the heap block */
addr = fsm_get_location(heapBlk, &slot);
new_cat = fsm_space_avail_to_cat(spaceAvail);
fsm_set_and_search(rel, addr, slot, new_cat, 0);
}
/*
* RecordAndGetPageWithFreeSpace - update info about a page and try again.
*
* We provide this combo form to save some locking overhead, compared to
* separate RecordPageWithFreeSpace + GetPageWithFreeSpace calls. There's
* also some effort to return a page close to the old page; if there's a
* page with enough free space on the same FSM page where the old one page
* is located, it is preferred.
*/
BlockNumber
RecordAndGetPageWithFreeSpace(Relation rel, BlockNumber oldPage,
Size oldSpaceAvail, Size spaceNeeded)
{
int old_cat = fsm_space_avail_to_cat(oldSpaceAvail);
int search_cat = fsm_space_needed_to_cat(spaceNeeded);
FSMAddress addr;
uint16 slot;
int search_slot;
/* Get the location of the FSM byte representing the heap block */
addr = fsm_get_location(oldPage, &slot);
search_slot = fsm_set_and_search(rel, addr, slot, old_cat, search_cat);
/*
* If fsm_set_and_search found a suitable new___ block, return that.
* Otherwise, search as usual.
*/
if (search_slot != -1)
return fsm_get_heap_blk(addr, search_slot);
else
return fsm_search(rel, search_cat);
}
/*
* Recursive guts of FreeSpaceMapVacuum
*
* Examine the FSM page indicated by addr, as well as its children, updating
* upper-level nodes that cover the heap block range from start to end-1.
* (It's okay if end is beyond the actual end of the map.)
* Return the maximum freespace value on this page.
*
* If addr is past the end of the FSM, set *eof_p to true and return 0.
*
* This traverses the tree in depth-first order. The tree is stored
* physically in depth-first order, so this should be pretty I/O efficient.
*/
static uint8
fsm_vacuum_page(Relation rel, FSMAddress addr,
BlockNumber start, BlockNumber end,
bool *eof_p)
{
Buffer buf;
Page page;
uint8 max_avail;
/* Read the page if it exists, or return EOF */
buf = fsm_readbuf(rel, addr, false);
if (!BufferIsValid(buf))
{
*eof_p = true;
return 0;
}
else
*eof_p = false;
page = BufferGetPage(buf);
/*
* If we're above the bottom level, recurse into children, and fix the
* information stored about them at this level.
*/
if (addr.level > FSM_BOTTOM_LEVEL)
{
FSMAddress fsm_start,
fsm_end;
uint16 fsm_start_slot,
fsm_end_slot;
int slot,
start_slot,
end_slot;
bool eof = false;
/*
* Compute the range of slots we need to update on this page, given
* the requested range of heap blocks to consider. The first slot to
* update is the one covering the "start" block, and the last slot is
* the one covering "end - 1". (Some of this work will be duplicated
* in each recursive call, but it's cheap enough to not worry about.)
*/
fsm_start = fsm_get_location(start, &fsm_start_slot);
fsm_end = fsm_get_location(end - 1, &fsm_end_slot);
while (fsm_start.level < addr.level)
{
fsm_start = fsm_get_parent(fsm_start, &fsm_start_slot);
fsm_end = fsm_get_parent(fsm_end, &fsm_end_slot);
}
Assert(fsm_start.level == addr.level);
if (fsm_start.logpageno == addr.logpageno)
start_slot = fsm_start_slot;
else if (fsm_start.logpageno > addr.logpageno)
start_slot = SlotsPerFSMPage; /* shouldn't get here... */
else
start_slot = 0;
if (fsm_end.logpageno == addr.logpageno)
end_slot = fsm_end_slot;
else if (fsm_end.logpageno > addr.logpageno)
end_slot = SlotsPerFSMPage - 1;
else
end_slot = -1; /* shouldn't get here... */
for (slot = start_slot; slot <= end_slot; slot++)
{
int child_avail;
CHECK_FOR_INTERRUPTS();
/* After we hit end-of-file, just clear the rest of the slots */
if (!eof)
child_avail = fsm_vacuum_page(rel, fsm_get_child(addr, slot),
start, end,
&eof);
else
child_avail = 0;
/* Update information about the child */
if (fsm_get_avail(page, slot) != child_avail)
{
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
fsm_set_avail(page, slot, child_avail);
MarkBufferDirtyHint(buf, false);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
}
}
/* Now get the maximum value on the page, to return to caller */
max_avail = fsm_get_max_avail(page);
/*
* Reset the next slot pointer. This encourages the use of low-numbered
* pages, increasing the chances that a later vacuum can truncate the
* relation. We don't bother with a lock here, nor with marking the page
* dirty if it wasn't already, since this is just a hint.
*/
((FSMPage) PageGetContents(page))->fp_next_slot = 0;
ReleaseBuffer(buf);
return max_avail;
}
/*
* FreeSpaceMapTruncateRel - adjust for truncation of a relation.
*
* The caller must hold AccessExclusiveLock on the relation, to ensure that
* other backends receive the smgr invalidation event that this function sends
* before they access the FSM again.
*
* nblocks is the new size of the heap.
*/
void
FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks)
{
BlockNumber new_nfsmblocks;
FSMAddress first_removed_address;
uint16 first_removed_slot;
Buffer buf;
RelationOpenSmgr(rel);
/*
* If no FSM has been created yet for this relation, there's nothing to
* truncate.
*/
if (!smgrexists(rel->rd_smgr, FSM_FORKNUM))
return;
/* Get the location in the FSM of the first removed heap block */
first_removed_address = fsm_get_location(nblocks, &first_removed_slot);
/*
* Zero out the tail of the last remaining FSM page. If the slot
* representing the first removed heap block is at a page boundary, as the
* first slot on the FSM page that first_removed_address points to, we can
* just truncate that page altogether.
*/
if (first_removed_slot > 0)
{
buf = fsm_readbuf(rel, first_removed_address, false);
if (!BufferIsValid(buf))
return; /* nothing to do; the FSM was already smaller */
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
/* NO EREPORT(ERROR) from here till changes are logged */
START_CRIT_SECTION();
fsm_truncate_avail(BufferGetPage(buf), first_removed_slot);
/*
* Truncation of a relation is WAL-logged at a higher-level, and we
* will be called at WAL replay. But if checksums are enabled, we need
* to still write a WAL record to protect against a torn page, if the
* page is flushed to disk before the truncation WAL record. We cannot
* use MarkBufferDirtyHint here, because that will not dirty the page
* during recovery.
*/
MarkBufferDirty(buf);
if (!InRecovery && RelationNeedsWAL(rel) && XLogHintBitIsNeeded())
log_newpage_buffer(buf, false);
END_CRIT_SECTION();
UnlockReleaseBuffer(buf);
new_nfsmblocks = fsm_logical_to_physical(first_removed_address) + 1;
}
else
{
new_nfsmblocks = fsm_logical_to_physical(first_removed_address);
if (smgrnblocks(rel->rd_smgr, FSM_FORKNUM) <= new_nfsmblocks)
return; /* nothing to do; the FSM was already smaller */
}
/* Truncate the unused FSM pages, and send smgr inval message */
smgrtruncate(rel->rd_smgr, FSM_FORKNUM, new_nfsmblocks);
/*
* We might as well update the local smgr_fsm_nblocks setting.
* smgrtruncate sent an smgr cache inval message, which will cause other
* backends to invalidate their copy of smgr_fsm_nblocks, and this one too
* at the next command boundary. But this ensures it isn't outright wrong
* until then.
*/
if (rel->rd_smgr)
rel->rd_smgr->smgr_fsm_nblocks = new_nfsmblocks;
/*
* Update upper-level FSM pages to account for the truncation. This is
* important because the just-truncated pages were likely marked as
* all-free, and would be preferentially selected.
*/
FreeSpaceMapVacuumRange(rel, nblocks, InvalidBlockNumber);
}
