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Redefine the lp_flags field of item pointers as having four states, rather

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than two independent bits (one of which was never used in heap pages anyway,
or at least hadn't been in a very long time).  This gives us flexibility to
add the HOT notions of redirected and dead item pointers without requiring
anything so klugy as magic values of lp_off and lp_len.  The state values
are chosen so that for the states currently in use (pre-HOT) there is no
change in the physical representation.
This commit is contained in:
Tom Lane
2007-09-12 22:10:26 +00:00
parent eb0a7735ba
commit 6889303531
31 changed files with 278 additions and 185 deletions
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30
src/backend/access/nbtree/nbtinsert.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.158 2007/06/03 22:16:02 petere Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.159 2007/09/12 22:10:26 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -221,7 +221,7 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
* we can. We only apply _bt_isequal() when we get to a non-killed
* item or the end of the page.
*/
if (!ItemIdDeleted(curitemid))
if (!ItemIdIsDead(curitemid))
{
/*
* _bt_compare returns 0 for (1,NULL) and (1,NULL) - this's
@ -301,7 +301,7 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
if (HeapTupleSatisfiesVacuum(htup.t_data, RecentGlobalXmin,
hbuffer) == HEAPTUPLE_DEAD)
{
curitemid->lp_flags |= LP_DELETE;
ItemIdMarkDead(curitemid);
opaque->btpo_flags |= BTP_HAS_GARBAGE;
/* be sure to mark the proper buffer dirty... */
if (nbuf != InvalidBuffer)
@ -368,7 +368,7 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel,
* any existing equal keys because of the way _bt_binsrch() works.
*
* If there's not enough room in the space, we try to make room by
* removing any LP_DELETEd tuples.
* removing any LP_DEAD tuples.
*
* On entry, *buf and *offsetptr point to the first legal position
* where the new tuple could be inserted. The caller should hold an
@ -449,7 +449,7 @@ _bt_findinsertloc(Relation rel,
/*
* before considering moving right, see if we can obtain enough
* space by erasing LP_DELETE items
* space by erasing LP_DEAD items
*/
if (P_ISLEAF(lpageop) && P_HAS_GARBAGE(lpageop))
{
@ -840,7 +840,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
itemsz = ItemIdGetLength(itemid);
item = (IndexTuple) PageGetItem(origpage, itemid);
if (PageAddItem(rightpage, (Item) item, itemsz, rightoff,
LP_USED) == InvalidOffsetNumber)
false) == InvalidOffsetNumber)
elog(PANIC, "failed to add hikey to the right sibling");
rightoff = OffsetNumberNext(rightoff);
}
@ -865,7 +865,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
item = (IndexTuple) PageGetItem(origpage, itemid);
}
if (PageAddItem(leftpage, (Item) item, itemsz, leftoff,
LP_USED) == InvalidOffsetNumber)
false) == InvalidOffsetNumber)
elog(PANIC, "failed to add hikey to the left sibling");
leftoff = OffsetNumberNext(leftoff);
@ -1699,7 +1699,8 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf)
* Note: we *must* insert the two items in item-number order, for the
* benefit of _bt_restore_page().
*/
if (PageAddItem(rootpage, (Item) new_item, itemsz, P_HIKEY, LP_USED) == InvalidOffsetNumber)
if (PageAddItem(rootpage, (Item) new_item, itemsz, P_HIKEY,
false) == InvalidOffsetNumber)
elog(PANIC, "failed to add leftkey to new root page");
pfree(new_item);
@ -1716,7 +1717,8 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf)
/*
* insert the right page pointer into the new root page.
*/
if (PageAddItem(rootpage, (Item) new_item, itemsz, P_FIRSTKEY, LP_USED) == InvalidOffsetNumber)
if (PageAddItem(rootpage, (Item) new_item, itemsz, P_FIRSTKEY,
false) == InvalidOffsetNumber)
elog(PANIC, "failed to add rightkey to new root page");
pfree(new_item);
@ -1803,7 +1805,7 @@ _bt_pgaddtup(Relation rel,
}
if (PageAddItem(page, (Item) itup, itemsize, itup_off,
LP_USED) == InvalidOffsetNumber)
false) == InvalidOffsetNumber)
elog(PANIC, "failed to add item to the %s for \"%s\"",
where, RelationGetRelationName(rel));
}
@ -1858,7 +1860,7 @@ _bt_isequal(TupleDesc itupdesc, Page page, OffsetNumber offnum,
/*
* _bt_vacuum_one_page - vacuum just one index page.
*
* Try to remove LP_DELETE items from the given page. The passed buffer
* Try to remove LP_DEAD items from the given page. The passed buffer
* must be exclusive-locked, but unlike a real VACUUM, we don't need a
* super-exclusive "cleanup" lock (see nbtree/README).
*/
@ -1875,7 +1877,7 @@ _bt_vacuum_one_page(Relation rel, Buffer buffer)
/*
* Scan over all items to see which ones need to be deleted
* according to LP_DELETE flags.
* according to LP_DEAD flags.
*/
minoff = P_FIRSTDATAKEY(opaque);
maxoff = PageGetMaxOffsetNumber(page);
@ -1885,7 +1887,7 @@ _bt_vacuum_one_page(Relation rel, Buffer buffer)
{
ItemId itemId = PageGetItemId(page, offnum);
if (ItemIdDeleted(itemId))
if (ItemIdIsDead(itemId))
deletable[ndeletable++] = offnum;
}
@ -1893,7 +1895,7 @@ _bt_vacuum_one_page(Relation rel, Buffer buffer)
_bt_delitems(rel, buffer, deletable, ndeletable);
/*
* Note: if we didn't find any LP_DELETE items, then the page's
* Note: if we didn't find any LP_DEAD items, then the page's
* BTP_HAS_GARBAGE hint bit is falsely set. We do not bother expending a
* separate write to clear it, however. We will clear it when we split
* the page.