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Improve traverseLeaves

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This commit is contained in:
Sebastian Messmer 2016-07-10 08:38:02 +02:00
parent 0d860fa4f0
commit dde89da556
2 changed files with 59 additions and 40 deletions
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89
src/blobstore/implementations/onblocks/datatreestore/DataTree.cpp
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@ -32,6 +32,7 @@ using cpputils::optional_ownership_ptr;
using cpputils::WithOwnership;
using cpputils::WithoutOwnership;
using cpputils::unique_ref;
using cpputils::Data;
namespace blobstore {
namespace onblocks {
@ -169,7 +170,7 @@ uint32_t DataTree::_computeNumLeaves(const DataNode &node) const {
return numLeavesInLeftChildren + numLeavesInRightChild;
}
void DataTree::traverseLeaves(uint32_t beginIndex, uint32_t endIndex, function<void (DataLeafNode*, uint32_t)> func) {
void DataTree::traverseLeaves(uint32_t beginIndex, uint32_t endIndex, std::function<void (uint32_t index, datanodestore::DataLeafNode* leaf)> onExistingLeaf, std::function<cpputils::Data (uint32_t index)> onCreateLeaf) {
//TODO Can we traverse in parallel?
boost::upgrade_lock<shared_mutex> lock(_mutex); //TODO Rethink locking here. We probably need locking when the traverse resizes the blob. Otherwise, parallel traverse should be possible. We already allow it below by freeing the upgrade_lock, but we currently only allow it if ALL traverses are entirely inside the valid region. Can we allow more parallelity?
auto exclusiveLock = std::make_unique<boost::upgrade_to_unique_lock<shared_mutex>>(lock);
@ -189,40 +190,49 @@ void DataTree::traverseLeaves(uint32_t beginIndex, uint32_t endIndex, function<v
if (numLeaves <= beginIndex) {
//TODO Test cases with numLeaves < / >= beginIndex
// There is a gap between the current size and the begin of the traversal
_traverseLeaves(_rootNode.get(), 0, numLeaves-1, endIndex, [beginIndex, numLeaves, &func, this](DataLeafNode* node, uint32_t index) {
if (index >= beginIndex) {
func(node, index);
} else if (index == numLeaves - 1) {
// It is the old last leaf - resize it to maximum
node->resize(_nodeStore->layout().maxBytesPerLeaf());
}
});
ASSERT(endIndex >= _numLeavesCache.value(), "We should be outside of the valid region, i.e. outside of the old size");
_numLeavesCache = endIndex;
} else if (numLeaves < endIndex) {
// We are starting traversal in the valid region, but traverse until after it (we grow new leaves)
_traverseLeaves(_rootNode.get(), 0, beginIndex, endIndex, [numLeaves, &func, this] (DataLeafNode *node, uint32_t index) {
auto _onExistingLeaf = [numLeaves, &onExistingLeaf, this](uint32_t index, DataLeafNode* node) {
if (index == numLeaves - 1) {
// It is the old last leaf - resize it to maximum
node->resize(_nodeStore->layout().maxBytesPerLeaf());
}
func(node, index);
});
onExistingLeaf(index, node);
};
auto _onCreateLeaf = [beginIndex, &onCreateLeaf, this](uint32_t index) {
if (index < beginIndex) {
// Create empty leaves in the gap
return Data(_nodeStore->layout().maxBytesPerLeaf()).FillWithZeroes();
} else {
return onCreateLeaf(index);
}
};
_traverseLeaves(_rootNode.get(), 0, numLeaves-1, endIndex, _onExistingLeaf, _onCreateLeaf);
ASSERT(endIndex >= _numLeavesCache.value(), "We should be outside of the valid region, i.e. outside of the old size");
_numLeavesCache = endIndex;
} else if (numLeaves < endIndex) {
// We are starting traversal in the valid region, but traverse until after it (we grow new leaves)
auto _onExistingLeaf = [numLeaves, &onExistingLeaf, this] (uint32_t index, DataLeafNode *node) {
if (index == numLeaves - 1) {
// It is the old last leaf - resize it to maximum
node->resize(_nodeStore->layout().maxBytesPerLeaf());
}
onExistingLeaf(index, node);
};
_traverseLeaves(_rootNode.get(), 0, beginIndex, endIndex, _onExistingLeaf, onCreateLeaf);
ASSERT(endIndex >= _numLeavesCache.value(), "We should be outside of the valid region, i.e. outside of the old size");
_numLeavesCache = endIndex;
} else {
//We are traversing entirely inside the valid region
exclusiveLock.reset(); // we can allow parallel traverses, if all are entirely inside the valid region.
_traverseLeaves(_rootNode.get(), 0, beginIndex, endIndex, func);
_traverseLeaves(_rootNode.get(), 0, beginIndex, endIndex, onExistingLeaf, onCreateLeaf);
}
}
void DataTree::_traverseLeaves(DataNode *root, uint32_t leafOffset, uint32_t beginIndex, uint32_t endIndex, function<void (DataLeafNode*, uint32_t)> func) {
void DataTree::_traverseLeaves(DataNode *root, uint32_t leafOffset, uint32_t beginIndex, uint32_t endIndex, std::function<void (uint32_t index, datanodestore::DataLeafNode* leaf)> onExistingLeaf, std::function<cpputils::Data (uint32_t index)> onCreateLeaf) {
DataLeafNode *leaf = dynamic_cast<DataLeafNode*>(root);
if (leaf != nullptr) {
ASSERT(beginIndex <= 1 && endIndex <= 1, "If root node is a leaf, the (sub)tree has only one leaf - access indices must be 0 or 1.");
if (beginIndex == 0 && endIndex == 1) {
func(leaf, leafOffset);
onExistingLeaf(leafOffset, leaf);
}
return;
}
@ -231,32 +241,41 @@ void DataTree::_traverseLeaves(DataNode *root, uint32_t leafOffset, uint32_t beg
uint32_t leavesPerChild = leavesPerFullChild(*inner);
uint32_t beginChild = beginIndex/leavesPerChild;
uint32_t endChild = utils::ceilDivision(endIndex, leavesPerChild);
vector<unique_ref<DataNode>> children = getOrCreateChildren(inner, beginChild, endChild);
for (uint32_t childIndex = beginChild; childIndex < endChild; ++childIndex) {
for (uint32_t childIndex = beginChild; childIndex < std::min(inner->numChildren(), endChild); ++childIndex) {
auto child = _nodeStore->load(inner->getChild(childIndex)->key());
ASSERT(child != none, "Couldn't load child node");
uint32_t childOffset = childIndex * leavesPerChild;
uint32_t localBeginIndex = utils::maxZeroSubtraction(beginIndex, childOffset);
uint32_t localEndIndex = std::min(leavesPerChild, endIndex - childOffset);
auto child = std::move(children[childIndex-beginChild]);
_traverseLeaves(child.get(), leafOffset + childOffset, localBeginIndex, localEndIndex, func);
_traverseLeaves(child->get(), leafOffset + childOffset, localBeginIndex, localEndIndex, onExistingLeaf, onCreateLeaf);
}
for (uint32_t childIndex = inner->numChildren(); childIndex < endChild; ++childIndex) {
uint32_t childOffset = childIndex * leavesPerChild;
uint32_t localEndIndex = std::min(leavesPerChild, endIndex - childOffset);
auto child = _createSubtree(leafOffset, localEndIndex, onCreateLeaf);
inner->addChild(child.key());
}
}
vector<unique_ref<DataNode>> DataTree::getOrCreateChildren(DataInnerNode *node, uint32_t begin, uint32_t end) {
unique_ref<DataNode> DataTree::_createSubtree(uint32_t leafOffset, uint32_t numLeaves, std::function<cpputils::Data (uint32_t index)> onCreateLeaf) {
if (numLeaves == 1) {
auto data = onCreateLeaf(leafOffset);
ASSERT(data.size() <= _nodeStore->layout().maxBytesPerLeaf(), "Too much data for a leaf");
//TODO More efficient by _nodeStore->createNewLeafNode(data);
auto leaf = _nodeStore->createNewLeafNode();
leaf->resize(data.size());
leaf->write(data.data(), 0, data.size());
return leaf;
} else {
uint32_t numLeafGroups = utils::ceilDivision(numLeaves, _nodeStore->layout().maxChildrenPerInnerNode());
vector<unique_ref<DataNode>> children;
children.reserve(end-begin);
for (uint32_t childIndex = begin; childIndex < std::min(node->numChildren(), end); ++childIndex) {
auto child = _nodeStore->load(node->getChild(childIndex)->key());
ASSERT(child != none, "Couldn't load child node");
children.emplace_back(std::move(*child));
children.reserve(numLeafGroups);
for (uint32_t i = 0; i < numLeafGroups; ++i) {
children.push_back(_createSubtree())
...
}
for (uint32_t childIndex = node->numChildren(); childIndex < end; ++childIndex) {
//TODO This creates each child with one chain to one leaf only, and then on the next lower level it
// has to create the children for the child. Would be faster to directly create full trees if necessary.
children.emplace_back(addChildTo(node));
}
ASSERT(children.size() == end-begin, "Number of children in the result is wrong");
return children;
}
unique_ref<DataNode> DataTree::addChildTo(DataInnerNode *node) {

6
src/blobstore/implementations/onblocks/datatreestore/DataTree.h
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@ -30,7 +30,7 @@ public:
//Returning uint64_t, because calculations handling this probably need to be done in 64bit to support >4GB blobs.
uint64_t maxBytesPerLeaf() const;
void traverseLeaves(uint32_t beginIndex, uint32_t endIndex, std::function<void (datanodestore::DataLeafNode*, uint32_t)> func);
void traverseLeaves(uint32_t beginIndex, uint32_t endIndex, std::function<void (uint32_t index, datanodestore::DataLeafNode* leaf)> onExistingLeaf, std::function<cpputils::Data (uint32_t index)> onCreateLeaf);
void resizeNumBytes(uint64_t newNumBytes);
uint32_t numLeaves() const;
@ -62,7 +62,7 @@ private:
void ifRootHasOnlyOneChildReplaceRootWithItsChild();
//TODO Use underscore for private methods
void _traverseLeaves(datanodestore::DataNode *root, uint32_t leafOffset, uint32_t beginIndex, uint32_t endIndex, std::function<void (datanodestore::DataLeafNode*, uint32_t)> func);
void _traverseLeaves(datanodestore::DataNode *root, uint32_t leafOffset, uint32_t beginIndex, uint32_t endIndex, std::function<void (uint32_t index, datanodestore::DataLeafNode* leaf)> onExistingLeaf, std::function<cpputils::Data (uint32_t index)> onCreateLeaf);
uint32_t leavesPerFullChild(const datanodestore::DataInnerNode &root) const;
uint64_t _numStoredBytes() const;
uint64_t _numStoredBytes(const datanodestore::DataNode &root) const;
@ -71,7 +71,7 @@ private:
cpputils::optional_ownership_ptr<datanodestore::DataLeafNode> LastLeaf(datanodestore::DataNode *root);
cpputils::unique_ref<datanodestore::DataLeafNode> LastLeaf(cpputils::unique_ref<datanodestore::DataNode> root);
datanodestore::DataInnerNode* increaseTreeDepth(unsigned int levels);
std::vector<cpputils::unique_ref<datanodestore::DataNode>> getOrCreateChildren(datanodestore::DataInnerNode *node, uint32_t begin, uint32_t end);
cpputils::unique_ref<datanodestore::DataNode> _createSubtree(uint32_t leafOffset, uint32_t numLeaves, std::function<cpputils::Data (uint32_t index)> onCreateLeaf);
cpputils::unique_ref<datanodestore::DataNode> addChildTo(datanodestore::DataInnerNode *node);
DISALLOW_COPY_AND_ASSIGN(DataTree);