/*
* Read tuples in correct sort order from tuplesort, and load them into
* btree leaves.
*/
static void
_bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
{
BTPageState *state = NULL;
bool merge = (btspool2 != NULL);
IndexTuple itup,
itup2 = NULL;
bool load1;
TupleDesc tupdes = RelationGetDescr(wstate->index);
int i,
keysz = RelationGetNumberOfAttributes(wstate->index);
ScanKey indexScanKey = NULL;
SortSupport sortKeys;
if (merge)
{
/*
* Another BTSpool for dead tuples exists. Now we have to merge
* btspool and btspool2.
*/
/* the preparation of merge */
itup = tuplesort_getindextuple(btspool->sortstate, true);
itup2 = tuplesort_getindextuple(btspool2->sortstate, true);
indexScanKey = _bt_mkscankey_nodata(wstate->index);
/* Prepare SortSupport data for each column */
sortKeys = (SortSupport) palloc0(keysz * sizeof(SortSupportData));
for (i = 0; i < keysz; i++)
{
SortSupport sortKey = sortKeys + i;
ScanKey scanKey = indexScanKey + i;
int16 strategy;
sortKey->ssup_cxt = CurrentMemoryContext;
sortKey->ssup_collation = scanKey->sk_collation;
sortKey->ssup_nulls_first =
(scanKey->sk_flags & SK_BT_NULLS_FIRST) != 0;
sortKey->ssup_attno = scanKey->sk_attno;
/* Abbreviation is not supported here */
sortKey->abbreviate = false;
AssertState(sortKey->ssup_attno != 0);
strategy = (scanKey->sk_flags & SK_BT_DESC) != 0 ?
BTGreaterStrategyNumber : BTLessStrategyNumber;
PrepareSortSupportFromIndexRel(wstate->index, strategy, sortKey);
}
_bt_freeskey(indexScanKey);
for (;;)
{
load1 = true; /* load BTSpool next ? */
if (itup2 == NULL)
{
if (itup == NULL)
break;
}
else if (itup != NULL)
{
for (i = 1; i <= keysz; i++)
{
SortSupport entry;
Datum attrDatum1,
attrDatum2;
bool isNull1,
isNull2;
int32 compare;
entry = sortKeys + i - 1;
attrDatum1 = index_getattr(itup, i, tupdes, &isNull1);
attrDatum2 = index_getattr(itup2, i, tupdes, &isNull2);
compare = ApplySortComparator(attrDatum1, isNull1,
attrDatum2, isNull2,
entry);
if (compare > 0)
{
load1 = false;
break;
}
else if (compare < 0)
break;
}
}
else
load1 = false;
/* When we see first tuple, create first index page */
if (state == NULL)
state = _bt_pagestate(wstate, 0);
if (load1)
{
_bt_buildadd(wstate, state, itup);
itup = tuplesort_getindextuple(btspool->sortstate, true);
}
else
{
_bt_buildadd(wstate, state, itup2);
itup2 = tuplesort_getindextuple(btspool2->sortstate, true);
}
}
pfree(sortKeys);
}
else
{
/* merge is unnecessary */
while ((itup = tuplesort_getindextuple(btspool->sortstate,
true)) != NULL)
{
/* When we see first tuple, create first index page */
if (state == NULL)
state = _bt_pagestate(wstate, 0);
_bt_buildadd(wstate, state, itup);
}
}
/* Close down final pages and write the metapage */
_bt_uppershutdown(wstate, state);
/*
* If the index is WAL-logged, we must fsync it down to disk before it's
* safe to commit the transaction. (For a non-WAL-logged index we don't
* care since the index will be uninteresting after a crash anyway.)
*
* It's obvious that we must do this when not WAL-logging the build. It's
* less obvious that we have to do it even if we did WAL-log the index
* pages. The reason is that since we're building outside shared buffers,
* a CHECKPOINT occurring during the build has no way to flush the
* previously written data to disk (indeed it won't know the index even
* exists). A crash later on would replay WAL from the checkpoint,
* therefore it wouldn't replay our earlier WAL entries. If we do not
* fsync those pages here, they might still not be on disk when the crash
* occurs.
*/
if (RelationNeedsWAL(wstate->index))
{
RelationOpenSmgr(wstate->index);
smgrimmedsync(wstate->index->rd_smgr, MAIN_FORKNUM);
}
}
/*
* Finish writing out the completed btree.
*/
static void
_bt_uppershutdown(BTWriteState *wstate, BTPageState *state)
{
BTPageState *s;
BlockNumber rootblkno = P_NONE;
uint32 rootlevel = 0;
Page metapage;
/*
* Each iteration of this loop completes one more level of the tree.
*/
for (s = state; s != NULL; s = s->btps_next)
{
BlockNumber blkno;
BTPageOpaque opaque;
blkno = s->btps_blkno;
opaque = (BTPageOpaque) PageGetSpecialPointer(s->btps_page);
/*
* We have to link the last page on this level to somewhere.
*
* If we're at the top, it's the root, so attach it to the metapage.
* Otherwise, add an entry for it to its parent using its minimum key.
* This may cause the last page of the parent level to split, but
* that's not a problem -- we haven't gotten to it yet.
*/
if (s->btps_next == NULL)
{
opaque->btpo_flags |= BTP_ROOT;
rootblkno = blkno;
rootlevel = s->btps_level;
}
else
{
Assert(s->btps_minkey != NULL);
ItemPointerSet(&(s->btps_minkey->t_tid), blkno, P_HIKEY);
_bt_buildadd(wstate, s->btps_next, s->btps_minkey);
pfree(s->btps_minkey);
s->btps_minkey = NULL;
}
/*
* This is the rightmost page, so the ItemId array needs to be slid
* back one slot. Then we can dump out the page.
*/
_bt_slideleft(s->btps_page);
_bt_blwritepage(wstate, s->btps_page, s->btps_blkno);
s->btps_page = NULL; /* writepage freed the workspace */
}
/*
* As the last step in the process, construct the metapage and make it
* point to the new root (unless we had no data at all, in which case it's
* set to point to "P_NONE"). This changes the index to the "valid" state
* by filling in a valid magic number in the metapage.
*/
metapage = (Page) palloc(BLCKSZ);
_bt_initmetapage(metapage, rootblkno, rootlevel);
_bt_blwritepage(wstate, metapage, BTREE_METAPAGE);
}
/*
* _bt_mergeload - Merge two streams of index tuples into new index files.
*/
static void
_bt_mergeload(Spooler *self, BTWriteState *wstate, BTSpool *btspool, BTReader *btspool2, Relation heapRel)
{
BTPageState *state = NULL;
IndexTuple itup,
itup2;
bool should_free = false;
TupleDesc tupdes = RelationGetDescr(wstate->index);
int keysz = RelationGetNumberOfAttributes(wstate->index);
ScanKey indexScanKey;
ON_DUPLICATE on_duplicate = self->on_duplicate;
Assert(btspool != NULL);
/* the preparation of merge */
itup = BTSpoolGetNextItem(btspool, NULL, &should_free);
itup2 = BTReaderGetNextItem(btspool2);
indexScanKey = _bt_mkscankey_nodata(wstate->index);
for (;;)
{
bool load1 = true; /* load BTSpool next ? */
bool hasnull;
int32 compare;
if (self->dup_old + self->dup_new > self->max_dup_errors)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("Maximum duplicate error count exceeded")));
if (itup2 == NULL)
{
if (itup == NULL)
break;
}
else if (itup != NULL)
{
compare = compare_indextuple(itup, itup2, indexScanKey,
keysz, tupdes, &hasnull);
if (compare == 0 && !hasnull && btspool->isunique)
{
ItemPointerData t_tid2;
/*
* t_tid is update by heap_is_visible(), because use it for an
* index, t_tid backup
*/
ItemPointerCopy(&itup2->t_tid, &t_tid2);
/* The tuple pointed by the old index should not be visible. */
if (!heap_is_visible(heapRel, &itup->t_tid))
{
itup = BTSpoolGetNextItem(btspool, itup, &should_free);
}
else if (!heap_is_visible(heapRel, &itup2->t_tid))
{
itup2 = BTReaderGetNextItem(btspool2);
}
else
{
if (on_duplicate == ON_DUPLICATE_KEEP_NEW)
{
self->dup_old++;
remove_duplicate(self, heapRel, itup2,
RelationGetRelationName(wstate->index));
itup2 = BTReaderGetNextItem(btspool2);
}
else
{
ItemPointerCopy(&t_tid2, &itup2->t_tid);
self->dup_new++;
remove_duplicate(self, heapRel, itup,
RelationGetRelationName(wstate->index));
itup = BTSpoolGetNextItem(btspool, itup, &should_free);
}
}
continue;
}
else if (compare > 0)
load1 = false;
}
else
load1 = false;
BULKLOAD_PROFILE(&prof_merge_unique);
/* When we see first tuple, create first index page */
if (state == NULL)
state = _bt_pagestate(wstate, 0);
if (load1)
{
IndexTuple next_itup = NULL;
bool next_should_free = false;
for (;;)
{
/* get next item */
next_itup = BTSpoolGetNextItem(btspool, next_itup,
&next_should_free);
if (!btspool->isunique || next_itup == NULL)
break;
compare = compare_indextuple(itup, next_itup, indexScanKey,
keysz, tupdes, &hasnull);
if (compare < 0 || hasnull)
break;
if (compare > 0)
{
/* shouldn't happen */
elog(ERROR, "faild in tuplesort_performsort");
}
/*
* If tupple is deleted by other unique indexes, not visible
*/
if (!heap_is_visible(heapRel, &next_itup->t_tid))
{
continue;
}
if (!heap_is_visible(heapRel, &itup->t_tid))
{
if (should_free)
pfree(itup);
itup = next_itup;
should_free = next_should_free;
next_should_free = false;
continue;
}
/* not unique between input files */
self->dup_new++;
remove_duplicate(self, heapRel, next_itup,
RelationGetRelationName(wstate->index));
if (self->dup_old + self->dup_new > self->max_dup_errors)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("Maximum duplicate error count exceeded")));
}
_bt_buildadd(wstate, state, itup);
if (should_free)
pfree(itup);
itup = next_itup;
should_free = next_should_free;
}
else
{
_bt_buildadd(wstate, state, itup2);
itup2 = BTReaderGetNextItem(btspool2);
}
BULKLOAD_PROFILE(&prof_merge_insert);
}
_bt_freeskey(indexScanKey);
/* Close down final pages and write the metapage */
_bt_uppershutdown(wstate, state);
/*
* If the index isn't temp, we must fsync it down to disk before it's safe
* to commit the transaction. (For a temp index we don't care since the
* index will be uninteresting after a crash anyway.)
*
* It's obvious that we must do this when not WAL-logging the build. It's
* less obvious that we have to do it even if we did WAL-log the index
* pages. The reason is that since we're building outside shared buffers,
* a CHECKPOINT occurring during the build has no way to flush the
* previously written data to disk (indeed it won't know the index even
* exists). A crash later on would replay WAL from the checkpoint,
* therefore it wouldn't replay our earlier WAL entries. If we do not
* fsync those pages here, they might still not be on disk when the crash
* occurs.
*/
if (!RELATION_IS_LOCAL(wstate->index))
{
RelationOpenSmgr(wstate->index);
smgrimmedsync(wstate->index->rd_smgr, MAIN_FORKNUM);
}
BULKLOAD_PROFILE(&prof_merge_term);
}
/*----------
* Add an item to a disk page from the sort output.
*
* We must be careful to observe the page layout conventions of nbtsearch.c:
* - rightmost pages start data items at P_HIKEY instead of at P_FIRSTKEY.
* - on non-leaf pages, the key portion of the first item need not be
* stored, we should store only the link.
*
* A leaf page being built looks like:
*
* +----------------+---------------------------------+
* | PageHeaderData | linp0 linp1 linp2 ... |
* +-----------+----+---------------------------------+
* | ... linpN | |
* +-----------+--------------------------------------+
* | ^ last |
* | |
* +-------------+------------------------------------+
* | | itemN ... |
* +-------------+------------------+-----------------+
* | ... item3 item2 item1 | "special space" |
* +--------------------------------+-----------------+
*
* Contrast this with the diagram in bufpage.h; note the mismatch
* between linps and items. This is because we reserve linp0 as a
* placeholder for the pointer to the "high key" item; when we have
* filled up the page, we will set linp0 to point to itemN and clear
* linpN. On the other hand, if we find this is the last (rightmost)
* page, we leave the items alone and slide the linp array over.
*
* 'last' pointer indicates the last offset added to the page.
*----------
*/
static void
_bt_buildadd(BTWriteState *wstate, BTPageState *state, IndexTuple itup)
{
Page npage;
BlockNumber nblkno;
OffsetNumber last_off;
Size pgspc;
Size itupsz;
/*
* This is a handy place to check for cancel interrupts during the btree
* load phase of index creation.
*/
CHECK_FOR_INTERRUPTS();
npage = state->btps_page;
nblkno = state->btps_blkno;
last_off = state->btps_lastoff;
pgspc = PageGetFreeSpace(npage);
itupsz = IndexTupleDSize(*itup);
itupsz = MAXALIGN(itupsz);
/*
* Check whether the item can fit on a btree page at all. (Eventually, we
* ought to try to apply TOAST methods if not.) We actually need to be
* able to fit three items on every page, so restrict any one item to 1/3
* the per-page available space. Note that at this point, itupsz doesn't
* include the ItemId.
*
* NOTE: similar code appears in _bt_insertonpg() to defend against
* oversize items being inserted into an already-existing index. But
* during creation of an index, we don't go through there.
*/
if (itupsz > BTMaxItemSize(npage))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("index row size %zu exceeds maximum %zu for index \"%s\"",
itupsz, BTMaxItemSize(npage),
RelationGetRelationName(wstate->index)),
errhint("Values larger than 1/3 of a buffer page cannot be indexed.\n"
"Consider a function index of an MD5 hash of the value, "
"or use full text indexing."),
errtableconstraint(wstate->heap,
RelationGetRelationName(wstate->index))));
/*
* Check to see if page is "full". It's definitely full if the item won't
* fit. Otherwise, compare to the target freespace derived from the
* fillfactor. However, we must put at least two items on each page, so
* disregard fillfactor if we don't have that many.
*/
if (pgspc < itupsz || (pgspc < state->btps_full && last_off > P_FIRSTKEY))
{
/*
* Finish off the page and write it out.
*/
Page opage = npage;
BlockNumber oblkno = nblkno;
ItemId ii;
ItemId hii;
IndexTuple oitup;
/* Create new page of same level */
npage = _bt_blnewpage(state->btps_level);
/* and assign it a page position */
nblkno = wstate->btws_pages_alloced++;
/*
* We copy the last item on the page into the new page, and then
* rearrange the old page so that the 'last item' becomes its high key
* rather than a true data item. There had better be at least two
* items on the page already, else the page would be empty of useful
* data.
*/
Assert(last_off > P_FIRSTKEY);
ii = PageGetItemId(opage, last_off);
oitup = (IndexTuple) PageGetItem(opage, ii);
_bt_sortaddtup(npage, ItemIdGetLength(ii), oitup, P_FIRSTKEY);
/*
* Move 'last' into the high key position on opage
*/
hii = PageGetItemId(opage, P_HIKEY);
*hii = *ii;
ItemIdSetUnused(ii); /* redundant */
((PageHeader) opage)->pd_lower -= sizeof(ItemIdData);
/*
* Link the old page into its parent, using its minimum key. If we
* don't have a parent, we have to create one; this adds a new btree
* level.
*/
if (state->btps_next == NULL)
state->btps_next = _bt_pagestate(wstate, state->btps_level + 1);
Assert(state->btps_minkey != NULL);
ItemPointerSet(&(state->btps_minkey->t_tid), oblkno, P_HIKEY);
_bt_buildadd(wstate, state->btps_next, state->btps_minkey);
pfree(state->btps_minkey);
/*
* Save a copy of the minimum key for the new page. We have to copy
* it off the old page, not the new one, in case we are not at leaf
* level.
*/
state->btps_minkey = CopyIndexTuple(oitup);
/*
* Set the sibling links for both pages.
*/
{
BTPageOpaque oopaque = (BTPageOpaque) PageGetSpecialPointer(opage);
BTPageOpaque nopaque = (BTPageOpaque) PageGetSpecialPointer(npage);
oopaque->btpo_next = nblkno;
nopaque->btpo_prev = oblkno;
nopaque->btpo_next = P_NONE; /* redundant */
}
/*
* Write out the old page. We never need to touch it again, so we can
* free the opage workspace too.
*/
_bt_blwritepage(wstate, opage, oblkno);
/*
* Reset last_off to point to new page
*/
last_off = P_FIRSTKEY;
}
/*
* If the new item is the first for its page, stash a copy for later. Note
* this will only happen for the first item on a level; on later pages,
* the first item for a page is copied from the prior page in the code
* above.
*/
if (last_off == P_HIKEY)
{
Assert(state->btps_minkey == NULL);
state->btps_minkey = CopyIndexTuple(itup);
}
/*
* Add the new item into the current page.
*/
last_off = OffsetNumberNext(last_off);
_bt_sortaddtup(npage, itupsz, itup, last_off);
state->btps_page = npage;
state->btps_blkno = nblkno;
state->btps_lastoff = last_off;
}
/*
* Read tuples in correct sort order from tuplesort, and load them into
* btree leaves.
*/
static void
_bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
{
BTPageState *state = NULL;
bool merge = (btspool2 != NULL);
IndexTuple itup,
itup2 = NULL;
bool should_free,
should_free2,
load1;
TupleDesc tupdes = RelationGetDescr(wstate->index);
int i,
keysz = RelationGetNumberOfAttributes(wstate->index);
ScanKey indexScanKey = NULL;
if (merge)
{
/*
* Another BTSpool for dead tuples exists. Now we have to merge
* btspool and btspool2.
*/
/* the preparation of merge */
itup = tuplesort_getindextuple(btspool->sortstate,
true, &should_free);
itup2 = tuplesort_getindextuple(btspool2->sortstate,
true, &should_free2);
indexScanKey = _bt_mkscankey_nodata(wstate->index);
for (;;)
{
load1 = true; /* load BTSpool next ? */
if (itup2 == NULL)
{
if (itup == NULL)
break;
}
else if (itup != NULL)
{
for (i = 1; i <= keysz; i++)
{
ScanKey entry;
Datum attrDatum1,
attrDatum2;
bool isNull1,
isNull2;
int32 compare;
entry = indexScanKey + i - 1;
attrDatum1 = index_getattr(itup, i, tupdes, &isNull1);
attrDatum2 = index_getattr(itup2, i, tupdes, &isNull2);
if (isNull1)
{
if (isNull2)
compare = 0; /* NULL "=" NULL */
else if (entry->sk_flags & SK_BT_NULLS_FIRST)
compare = -1; /* NULL "<" NOT_NULL */
else
compare = 1; /* NULL ">" NOT_NULL */
}
else if (isNull2)
{
if (entry->sk_flags & SK_BT_NULLS_FIRST)
compare = 1; /* NOT_NULL ">" NULL */
else
compare = -1; /* NOT_NULL "<" NULL */
}
else
{
compare =
DatumGetInt32(FunctionCall2Coll(&entry->sk_func,
entry->sk_collation,
attrDatum1,
attrDatum2));
if (entry->sk_flags & SK_BT_DESC)
compare = -compare;
}
if (compare > 0)
{
load1 = false;
break;
}
else if (compare < 0)
break;
}
}
else
load1 = false;
/* When we see first tuple, create first index page */
if (state == NULL)
state = _bt_pagestate(wstate, 0);
if (load1)
{
_bt_buildadd(wstate, state, itup);
if (should_free)
pfree(itup);
itup = tuplesort_getindextuple(btspool->sortstate,
true, &should_free);
}
else
{
_bt_buildadd(wstate, state, itup2);
if (should_free2)
pfree(itup2);
itup2 = tuplesort_getindextuple(btspool2->sortstate,
true, &should_free2);
}
}
_bt_freeskey(indexScanKey);
}
else
{
/* merge is unnecessary */
while ((itup = tuplesort_getindextuple(btspool->sortstate,
true, &should_free)) != NULL)
{
/* When we see first tuple, create first index page */
if (state == NULL)
state = _bt_pagestate(wstate, 0);
_bt_buildadd(wstate, state, itup);
if (should_free)
pfree(itup);
}
}
/* Close down final pages and write the metapage */
_bt_uppershutdown(wstate, state);
/*
* If the index is WAL-logged, we must fsync it down to disk before it's
* safe to commit the transaction. (For a non-WAL-logged index we don't
* care since the index will be uninteresting after a crash anyway.)
*
* It's obvious that we must do this when not WAL-logging the build. It's
* less obvious that we have to do it even if we did WAL-log the index
* pages. The reason is that since we're building outside shared buffers,
* a CHECKPOINT occurring during the build has no way to flush the
* previously written data to disk (indeed it won't know the index even
* exists). A crash later on would replay WAL from the checkpoint,
* therefore it wouldn't replay our earlier WAL entries. If we do not
* fsync those pages here, they might still not be on disk when the crash
* occurs.
*/
if (RelationNeedsWAL(wstate->index))
{
RelationOpenSmgr(wstate->index);
smgrimmedsync(wstate->index->rd_smgr, MAIN_FORKNUM);
}
}
