85 lines
2.5 KiB
C
85 lines
2.5 KiB
C
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#ifndef _LSMTREE_H__
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#define _LSMTREE_H__
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/**
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@file
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A log structured merge tree implementation. This implementation
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performs atomic bulk append operations to reduce logging overheads,
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and does not support in place updates.
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However, once written, the page format of internal nodes is similar
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to that of a conventional b-tree, while leaf nodes may be provided
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by any page type that allows records to be appendend to a page, and
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read by slot id.
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For now, LSM-trees only support fixed length keys; this restriction
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will be lifted in the future.
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*/
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#include <assert.h>
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#include <stasis/iterator.h>
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typedef struct {
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recordid treeRoot;
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recordid pos;
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} lladd_lsm_iterator;
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typedef struct {
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int id;
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// fcn pointer...
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} comparator_impl;
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void lsmTreeRegisterComparator(comparator_impl i);
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extern const int MAX_LSM_COMPARATORS;
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/**
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Initialize a new LSM tree.
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@param comparator. The id of the comparator this tree should use.
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(It must have been registered with lsmTreeRegisterComparator
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before TlsmCreate() is called.
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*/
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recordid TlsmCreate(int xid, int comparator, int keySize);
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/**
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Free the space associated with an LSM tree.
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*/
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recordid TlsmDealloc(int xid, recordid tree);
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/**
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Append a new leaf page to an LSM tree. Leaves must be appended in
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ascending order; LSM trees do not support update in place.
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*/
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recordid TlsmAppendPage(int xid, recordid tree,
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const byte *key, size_t keySize,
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long pageid);
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/**
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Lookup a leaf page.
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@param key The value you're looking for. The first page that may
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contain this value will be returned. (lsmTree supports
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duplicate keys...)
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@param keySize Must match the keySize passed to TlsmCreate.
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Currently unused.
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*/
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pageid_t TlsmFindPage(int xid, recordid tree,
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const byte *key, size_t keySize);
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/**
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Return a forward iterator over the tree's leaf pages (*not* their
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contents).
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*/
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lladdIterator_t * TlsmIterator(int xid, recordid hash);
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/**
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These are the functions that implement lsmTree's iterator.
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They're public so that performance critical code can call them
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without paying for a virtual method invocation.
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XXX should they be public?
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*/
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void lsmTreeIterator_close(int xid, void * it);
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int lsmTreeIterator_next (int xid, void * it);
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int lsmTreeIterator_key (int xid, void * it, byte **key);
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int lsmTreeIterator_value(int xid, void * it, byte **value);
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#endif // _LSMTREE_H__
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