/*
* ginbuildempty() -- build an empty gin index in the initialization fork
*/
Datum
ginbuildempty(PG_FUNCTION_ARGS)
{
Relation index = (Relation) PG_GETARG_POINTER(0);
Buffer RootBuffer,
MetaBuffer;
/* An empty GIN index has two pages. */
MetaBuffer =
ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
LockBuffer(MetaBuffer, BUFFER_LOCK_EXCLUSIVE);
RootBuffer =
ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
LockBuffer(RootBuffer, BUFFER_LOCK_EXCLUSIVE);
/* Initialize and xlog metabuffer and root buffer. */
START_CRIT_SECTION();
GinInitMetabuffer(MetaBuffer);
MarkBufferDirty(MetaBuffer);
log_newpage_buffer(MetaBuffer);
GinInitBuffer(RootBuffer, GIN_LEAF);
MarkBufferDirty(RootBuffer);
log_newpage_buffer(RootBuffer);
END_CRIT_SECTION();
/* Unlock and release the buffers. */
UnlockReleaseBuffer(MetaBuffer);
UnlockReleaseBuffer(RootBuffer);
PG_RETURN_VOID();
}
/*
* ginbuildempty() -- build an empty gin index in the initialization fork
*/
void
ginbuildempty(Relation index)
{
Buffer RootBuffer,
MetaBuffer;
/* An empty GIN index has two pages. */
MetaBuffer =
ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
LockBuffer(MetaBuffer, BUFFER_LOCK_EXCLUSIVE);
RootBuffer =
ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
LockBuffer(RootBuffer, BUFFER_LOCK_EXCLUSIVE);
/* Initialize and xlog metabuffer and root buffer. */
START_CRIT_SECTION();
GinInitMetabuffer(MetaBuffer);
MarkBufferDirty(MetaBuffer);
log_newpage_buffer(MetaBuffer, true);
GinInitBuffer(RootBuffer, GIN_LEAF);
MarkBufferDirty(RootBuffer);
log_newpage_buffer(RootBuffer, false);
END_CRIT_SECTION();
/* Unlock and release the buffers. */
UnlockReleaseBuffer(MetaBuffer);
UnlockReleaseBuffer(RootBuffer);
}
/*
* gistbuildempty() -- build an empty gist index in the initialization fork
*/
void
gistbuildempty(Relation index)
{
Buffer buffer;
/* Initialize the root page */
buffer = ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/* Initialize and xlog buffer */
START_CRIT_SECTION();
GISTInitBuffer(buffer, F_LEAF);
MarkBufferDirty(buffer);
log_newpage_buffer(buffer, true);
END_CRIT_SECTION();
/* Unlock and release the buffer */
UnlockReleaseBuffer(buffer);
}
void
brinbuildempty(Relation index)
{
Buffer metabuf;
/* An empty BRIN index has a metapage only. */
metabuf =
ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
LockBuffer(metabuf, BUFFER_LOCK_EXCLUSIVE);
/* Initialize and xlog metabuffer. */
START_CRIT_SECTION();
brin_metapage_init(BufferGetPage(metabuf), BrinGetPagesPerRange(index),
BRIN_CURRENT_VERSION);
MarkBufferDirty(metabuf);
log_newpage_buffer(metabuf, false);
END_CRIT_SECTION();
UnlockReleaseBuffer(metabuf);
}
/*
* gistbuildempty() -- build an empty gist index in the initialization fork
*/
Datum
gistbuildempty(PG_FUNCTION_ARGS)
{
Relation index = (Relation) PG_GETARG_POINTER(0);
Buffer buffer;
/* Initialize the root page */
buffer = ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/* Initialize and xlog buffer */
START_CRIT_SECTION();
GISTInitBuffer(buffer, F_LEAF);
MarkBufferDirty(buffer);
log_newpage_buffer(buffer, true);
END_CRIT_SECTION();
/* Unlock and release the buffer */
UnlockReleaseBuffer(buffer);
PG_RETURN_VOID();
}
/*
* Initialize a page as an empty regular BRIN page, WAL-log this, and record
* the page in FSM.
*
* There are several corner situations in which we extend the relation to
* obtain a new page and later find that we cannot use it immediately. When
* that happens, we don't want to leave the page go unrecorded in FSM, because
* there is no mechanism to get the space back and the index would bloat.
* Also, because we would not WAL-log the action that would initialize the
* page, the page would go uninitialized in a standby (or after recovery).
*/
static void
brin_initialize_empty_new_buffer(Relation idxrel, Buffer buffer)
{
Page page;
BRIN_elog((DEBUG2,
"brin_initialize_empty_new_buffer: initializing blank page %u",
BufferGetBlockNumber(buffer)));
START_CRIT_SECTION();
page = BufferGetPage(buffer);
brin_page_init(page, BRIN_PAGETYPE_REGULAR);
MarkBufferDirty(buffer);
log_newpage_buffer(buffer, true);
END_CRIT_SECTION();
/*
* We update the FSM for this page, but this is not WAL-logged. This is
* acceptable because VACUUM will scan the index and update the FSM with
* pages whose FSM records were forgotten in a crash.
*/
RecordPageWithFreeSpace(idxrel, BufferGetBlockNumber(buffer),
br_page_get_freespace(page));
}
/*
* 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);
}
