diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtsort.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtsort.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c index 1dd3be0a63..f2b1116b72 100644 --- a/src/backend/access/nbtree/nbtsort.c +++ b/src/backend/access/nbtree/nbtsort.c @@ -27,10 +27,10 @@ * insertion would cause a split (and not only of the leaf page; the need * for a split would cascade right up the tree). The steady-state load * factor for btrees is usually estimated at 70%. We choose to pack leaf - * pages to the user-controllable fill factor while upper pages are always - * packed to 70%. This gives us reasonable density (there aren't many upper - * pages if the keys are reasonable-size) without incurring a lot of cascading - * splits during early insertions. + * pages to the user-controllable fill factor (default 90%) while upper pages + * are always packed to 70%. This gives us reasonable density (there aren't + * many upper pages if the keys are reasonable-size) without risking a lot of + * cascading splits during early insertions. * * Formerly the index pages being built were kept in shared buffers, but * that is of no value (since other backends have no interest in them yet) @@ -57,7 +57,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsort.c,v 1.104 2006/07/03 22:45:37 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsort.c,v 1.105 2006/07/11 21:05:57 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -349,7 +349,7 @@ _bt_pagestate(BTWriteState *wstate, uint32 level) state->btps_level = level; /* set "full" threshold based on level. See notes at head of file. */ if (level > 0) - state->btps_full = (BLCKSZ * (100 - BTREE_MIN_FILLFACTOR) / 100); + state->btps_full = (BLCKSZ * (100 - BTREE_NONLEAF_FILLFACTOR) / 100); else state->btps_full = RelationGetTargetPageFreeSpace(wstate->index, BTREE_DEFAULT_FILLFACTOR); @@ -499,11 +499,16 @@ _bt_buildadd(BTWriteState *wstate, BTPageState *state, IndexTuple itup) "Consider a function index of an MD5 hash of the value, " "or use full text indexing."))); - if (pgspc < itupsz || pgspc < state->btps_full) + /* + * 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)) { /* - * Item won't fit on this page, or we feel the page is full enough - * already. Finish off the page and write it out. + * Finish off the page and write it out. */ Page opage = npage; BlockNumber oblkno = nblkno; @@ -522,8 +527,7 @@ _bt_buildadd(BTWriteState *wstate, BTPageState *state, IndexTuple itup) * 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. (Hence, we must allow pages to be packed at least 2/3rds - * full; the 70% figure used above is close to minimum.) + * data. */ Assert(last_off > P_FIRSTKEY); ii = PageGetItemId(opage, last_off); |