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| author | Michael Cahill <michael.cahill@wiredtiger.com> | 2014-04-03 21:42:33 +1100 |
|---|---|---|
| committer | Michael Cahill <michael.cahill@wiredtiger.com> | 2014-04-03 21:42:33 +1100 |
| commit | 3c6b862ff46d29016df9d30f16b28f7cae64f929 (patch) | |
| tree | 95e595bb33a94151d3a35c98219b770347c45d8f /src/btree/rec_split.c | |
| parent | 31a1675963d4ff99d5445461cd10051367fe034d (diff) | |
| download | mongo-3c6b862ff46d29016df9d30f16b28f7cae64f929.tar.gz | |
Flip the logic around when to deepen the tree -- there is no point trying to deepen if there aren't enough children for the split.
Deepen sooner: when leaves grow and split in two repeatedly, it takes a lot of re-allocation for the parent to reach 200K children.
Diffstat (limited to 'src/btree/rec_split.c')
| -rw-r--r-- | src/btree/rec_split.c | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/src/btree/rec_split.c b/src/btree/rec_split.c index 27ae2f9a512..5bb4e231aa5 100644 --- a/src/btree/rec_split.c +++ b/src/btree/rec_split.c @@ -12,8 +12,8 @@ * any real understanding of what might be useful to surface to applications. */ static u_int __split_deepen_max_internal_image = 100; -static u_int __split_deepen_min_child = 200; -static u_int __split_deepen_per_child = 1000; +static u_int __split_deepen_min_child = 100; +static u_int __split_deepen_per_child = 100; /* * __split_should_deepen -- @@ -30,30 +30,26 @@ __split_should_deepen(WT_SESSION_IMPL *session, WT_PAGE *page) * to search), or by the memory footprint of the parent page (avoiding * an internal page that will eat up all of the cache and put eviction * pressure on the system). - * - * Paranoia: don't try and split if we don't have anything to split. */ pindex = WT_INTL_INDEX_COPY(page); - if (pindex->entries < 50) - return (0); /* - * Split to deepen the tree if the page's memory footprint is N times - * the maximum internal page size chunk in the backing file. + * Don't deepen the tree if the page's memory footprint is less than N + * times the maximum internal page size chunk in the backing file. */ - if (page->memory_footprint > + if (page->memory_footprint < __split_deepen_max_internal_image * S2BT(session)->maxintlpage) - return (1); + return (0); /* - * Split to deepen the tree if the split will result in at least N + * Don't deepen the tree unless the split will result in at least N * children in the newly created intermediate layer. */ - if (pindex->entries > + if (pindex->entries < (__split_deepen_per_child * __split_deepen_min_child)) - return (1); + return (0); - return (0); + return (1); } /* |