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fix a bug in btree lookup

This commit is contained in:
Joe Thornber 2011-11-01 11:31:03 +00:00
parent 5c7287929a
commit 9cee046594
3 changed files with 119 additions and 37 deletions
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29
btree.h
View File

@ -97,6 +97,7 @@ namespace persistent_data {
void set_max_entries(); // calculates the max for you.
size_t get_value_size() const;
void set_value_size(size_t);
uint64_t key_at(unsigned i) const;
void set_key(unsigned i, uint64_t k);
@ -258,30 +259,6 @@ namespace persistent_data {
std::list<block_manager<>::write_ref> spine_;
block_address root_;
};
// FIXME: make a member of btree
template <typename ValueTraits>
optional<typename ValueTraits::value_type>
lookup_raw(ro_spine &spine, block_address block, uint64_t key) {
using namespace boost;
typedef typename ValueTraits::value_type leaf_type;
for (;;) {
spine.step(block);
node_ref<ValueTraits> leaf = spine.template get_node<ValueTraits>();
optional<unsigned> mi = leaf.exact_search(key);
if (!mi)
return optional<leaf_type>();
if (leaf.get_type() == btree_detail::LEAF)
return optional<leaf_type>(leaf.value_at(*mi));
node_ref<uint64_traits> internal = spine.template get_node<uint64_traits>();
block = internal.value_at(*mi);
}
}
}
template <unsigned Levels, typename ValueTraits>
@ -346,6 +323,10 @@ namespace persistent_data {
void visit(typename visitor::ptr visitor) const;
private:
template <typename ValueTraits2, typename Search>
optional<typename ValueTraits2::value_type>
lookup_raw(btree_detail::ro_spine &spine, block_address block, uint64_t key) const;
template <typename ValueTraits2>
void split_node(btree_detail::shadow_spine &spine,
block_address parent_index,

73
btree.tcc
View File

@ -102,6 +102,13 @@ node_ref<ValueTraits>::get_value_size() const
return to_cpu<uint32_t>(raw_->header.value_size);
}
template <typename ValueTraits>
void
node_ref<ValueTraits>::set_value_size(size_t s)
{
raw_->header.value_size = to_disk<__le32>(static_cast<uint32_t>(s));
}
template <typename ValueTraits>
uint64_t
node_ref<ValueTraits>::key_at(unsigned i) const
@ -181,9 +188,9 @@ node_ref<ValueTraits>::copy_entries(node_ref const &rhs,
if ((n + count) > get_max_entries())
throw runtime_error("too many entries");
set_nr_entries(n + count);
::memcpy(key_ptr(n), rhs.key_ptr(begin), sizeof(uint64_t) * count);
::memcpy(value_ptr(n), rhs.value_ptr(begin), sizeof(typename ValueTraits::disk_type) * count);
set_nr_entries(n + count);
}
template <typename ValueTraits>
@ -216,6 +223,9 @@ node_ref<ValueTraits>::exact_search(uint64_t key) const
if (i < 0 || static_cast<unsigned>(i) >= get_nr_entries())
return optional<unsigned>();
if (key != key_at(i))
return optional<unsigned>();
return optional<unsigned>(i);
}
@ -287,6 +297,7 @@ btree(typename transaction_manager::ptr tm,
n.set_type(btree_detail::LEAF);
n.set_nr_entries(0);
n.set_max_entries();
n.set_value_size(sizeof(typename ValueTraits::disk_type));
root_ = root.get_location();
}
@ -309,6 +320,22 @@ btree<Levels, ValueTraits>::~btree()
}
namespace {
template <typename ValueTraits>
struct lower_bound_search {
static optional<unsigned> search(btree_detail::node_ref<ValueTraits> n, uint64_t key) {
return n.lower_bound(key);
}
};
template <typename ValueTraits>
struct exact_search {
static optional<unsigned> search(btree_detail::node_ref<ValueTraits> n, uint64_t key) {
return n.exact_search(key);
}
};
}
template <unsigned Levels, typename ValueTraits>
typename btree<Levels, ValueTraits>::maybe_value
btree<Levels, ValueTraits>::lookup(key const &key) const
@ -320,14 +347,14 @@ btree<Levels, ValueTraits>::lookup(key const &key) const
for (unsigned level = 0; level < Levels - 1; ++level) {
optional<block_address> mroot =
lookup_raw<uint64_traits>(spine, root, key[level]);
lookup_raw<uint64_traits, lower_bound_search<uint64_traits> >(spine, root, key[level]);
if (!mroot)
return maybe_value();
root = *mroot;
}
return lookup_raw<ValueTraits>(spine, root, key[Levels - 1]);
return lookup_raw<ValueTraits, exact_search<ValueTraits> >(spine, root, key[Levels - 1]);
}
template <unsigned Levels, typename ValueTraits>
@ -422,6 +449,38 @@ btree<Levels, ValueTraits>::destroy()
}
#endif
template <unsigned Levels, typename _>
template <typename ValueTraits, typename Search>
optional<typename ValueTraits::value_type>
btree<Levels, _>::
lookup_raw(ro_spine &spine, block_address block, uint64_t key) const
{
using namespace boost;
typedef typename ValueTraits::value_type leaf_type;
for (;;) {
spine.step(block);
node_ref<ValueTraits> leaf = spine.template get_node<ValueTraits>();
optional<unsigned> mi;
if (leaf.get_type() == btree_detail::LEAF) {
mi = Search::search(leaf, key);
if (!mi)
return optional<leaf_type>();
return optional<leaf_type>(leaf.value_at(*mi));
}
mi = leaf.lower_bound(key);
if (!mi || *mi < 0)
return optional<leaf_type>();
node_ref<uint64_traits> internal = spine.template get_node<uint64_traits>();
block = internal.value_at(*mi);
}
}
template <unsigned Levels, typename _>
template <typename ValueTraits>
void
@ -456,14 +515,20 @@ split_beneath(btree_detail::shadow_spine &spine,
node_ref<ValueTraits> l = to_node<ValueTraits>(left);
l.set_nr_entries(0);
l.set_max_entries();
l.set_value_size(sizeof(typename ValueTraits::disk_type));
write_ref right = tm_->new_block();
node_ref<ValueTraits> r = to_node<ValueTraits>(right);
r.set_nr_entries(0);
r.set_max_entries();
r.set_value_size(sizeof(typename ValueTraits::disk_type));
{
node_ref<ValueTraits> p = spine.template get_node<ValueTraits>();
if (p.get_value_size() != sizeof(typename ValueTraits::disk_type))
throw std::runtime_error("bad value_size");
nr_left = p.get_nr_entries() / 2;
nr_right = p.get_nr_entries() - nr_left;
type = p.get_type();
@ -480,8 +545,8 @@ split_beneath(btree_detail::shadow_spine &spine,
internal_node p = spine.template get_node<uint64_traits>();
p.set_type(btree_detail::INTERNAL);
p.set_nr_entries(2);
p.set_value_size(sizeof(typename uint64_traits::disk_type));
// FIXME: set the value_size
p.overwrite_at(0, l.key_at(0), left.get_location());
p.overwrite_at(1, r.key_at(0), right.get_location());
}

54
unit-tests/btree_t.cc
View File

@ -1,5 +1,5 @@
#include "transaction_manager.h"
#include "core_map.h"
#include "space_map_core.h"
#include "btree.h"
#define BOOST_TEST_MODULE BTreeTests
@ -16,7 +16,7 @@ namespace {
transaction_manager::ptr
create_tm() {
block_manager<>::ptr bm(new block_manager<>("./test.data", NR_BLOCKS));
block_manager<>::ptr bm(new block_manager<>("./test.data", NR_BLOCKS, 4, true));
space_map::ptr sm(new core_map(NR_BLOCKS));
transaction_manager::ptr tm(new transaction_manager(bm, sm));
return tm;
@ -36,17 +36,26 @@ namespace {
//
class constraint_visitor : public btree<1, uint64_traits>::visitor {
public:
bool visit_internal(unsigned level, bool is_root, btree_detail::node_ref<uint64_traits> const &n) {
typedef btree_detail::node_ref<uint64_traits> internal_node;
typedef btree_detail::node_ref<uint64_traits> leaf_node;
bool visit_internal(unsigned level, bool sub_root,
boost::optional<uint64_t> key,
internal_node const &n) {
check_duplicate_block(n.get_location());
return true;
}
bool visit_internal_leaf(unsigned level, bool is_root, btree_detail::node_ref<uint64_traits> const &n) {
bool visit_internal_leaf(unsigned level, bool sub_root,
boost::optional<uint64_t> key,
internal_node const &n) {
check_duplicate_block(n.get_location());
return true;
}
bool visit_leaf(unsigned level, bool is_root, btree_detail::node_ref<uint64_traits> const &n) {
bool visit_leaf(unsigned level, bool sub_root,
boost::optional<uint64_t> key,
leaf_node const &n) {
check_duplicate_block(n.get_location());
return true;
}
@ -77,7 +86,7 @@ namespace {
BOOST_AUTO_TEST_CASE(empty_btree_contains_nothing)
{
auto tree = create_btree();
btree<1, uint64_traits>::ptr tree = create_btree();
check_constraints(tree);
for (uint64_t i = 0; i < 1000; i++) {
@ -90,19 +99,46 @@ BOOST_AUTO_TEST_CASE(insert_works)
{
unsigned const COUNT = 100000;
auto tree = create_btree();
btree<1, uint64_traits>::ptr tree = create_btree();
for (uint64_t i = 0; i < COUNT; i++) {
uint64_t key[1] = {i * 7};
uint64_t value = i;
tree->insert(key, value);
auto l = tree->lookup(key);
BOOST_CHECK(l);
btree<1, uint64_traits>::maybe_value l = tree->lookup(key);
BOOST_REQUIRE(l);
BOOST_CHECK_EQUAL(*l, i);
}
check_constraints(tree);
}
BOOST_AUTO_TEST_CASE(insert_does_not_insert_imaginary_values)
{
btree<1, uint64_traits>::ptr tree = create_btree();
uint64_t key[1] = {0};
uint64_t value = 100;
btree<1, uint64_traits>::maybe_value l = tree->lookup(key);
BOOST_CHECK(!l);
key[0] = 1;
l = tree->lookup(key);
BOOST_CHECK(!l);
key[0] = 0;
tree->insert(key, value);
l = tree->lookup(key);
BOOST_REQUIRE(l);
BOOST_CHECK_EQUAL(*l, 100);
key[0] = 1;
l = tree->lookup(key);
BOOST_CHECK(!l);
check_constraints(tree);
}
//----------------------------------------------------------------