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/*
Copyright (c) 2016, Facebook, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#pragma once
/* MySQL header files */
#include "../sql/log.h"
#include "./handler.h" /* handler */
#include "./my_global.h" /* ulonglong */
/* C++ standard header files */
#include <set>
#include <vector>
#include <queue>
/* RocksDB header files */
#include "rocksdb/db.h"
/* MyRocks header files */
#include "./rdb_comparator.h"
namespace myrocks {
/*
Length of delimiters used during inplace index creation.
*/
#define RDB_MERGE_CHUNK_LEN sizeof(size_t)
#define RDB_MERGE_REC_DELIMITER sizeof(size_t)
#define RDB_MERGE_KEY_DELIMITER RDB_MERGE_REC_DELIMITER
#define RDB_MERGE_VAL_DELIMITER RDB_MERGE_REC_DELIMITER
class Rdb_key_def;
class Rdb_tbl_def;
class Rdb_index_merge {
Rdb_index_merge(const Rdb_index_merge& p)= delete;
Rdb_index_merge& operator=(const Rdb_index_merge& p)= delete;
public:
/* Information about temporary files used in external merge sort */
struct merge_file_info {
File fd= -1; /* file descriptor */
ulong num_sort_buffers; /* number of sort buffers in temp file */
};
/* Buffer for sorting in main memory. */
struct merge_buf_info {
/* heap memory allocated for main memory sort/merge */
std::unique_ptr<uchar[]> block;
const ulonglong block_len; /* amount of data bytes allocated for block above */
ulonglong curr_offset; /* offset of the record pointer for the block */
ulonglong disk_start_offset; /* where the chunk starts on disk */
ulonglong disk_curr_offset; /* current offset on disk */
ulonglong total_size; /* total # of data bytes in chunk */
void store_key_value(const rocksdb::Slice& key, const rocksdb::Slice& val)
__attribute__((__nonnull__));
void store_slice(const rocksdb::Slice& slice)
__attribute__((__nonnull__));
size_t prepare(File fd, ulonglong f_offset)
__attribute__((__nonnull__));
int read_next_chunk_from_disk(File fd)
__attribute__((__nonnull__, __warn_unused_result__));
inline bool is_chunk_finished() const
{
return curr_offset + disk_curr_offset - disk_start_offset == total_size;
}
inline bool has_space(uint64 needed) const
{
return curr_offset + needed <= block_len;
}
explicit merge_buf_info(const ulonglong merge_block_size) :
block(nullptr), block_len(merge_block_size), curr_offset(0),
disk_start_offset(0), disk_curr_offset(0), total_size(merge_block_size)
{
/* Will throw an exception if it runs out of memory here */
block= std::unique_ptr<uchar[]>(new uchar[merge_block_size]);
/* Initialize entire buffer to 0 to avoid valgrind errors */
memset(block.get(), 0, merge_block_size);
}
};
/* Represents an entry in the heap during merge phase of external sort */
struct merge_heap_entry
{
std::shared_ptr<merge_buf_info> chunk_info; /* pointer to buffer info */
uchar* block; /* pointer to heap memory where record is stored */
const rocksdb::Comparator* const comparator;
rocksdb::Slice key; /* current key pointed to by block ptr */
rocksdb::Slice val;
size_t prepare(File fd, ulonglong f_offset, ulonglong chunk_size)
__attribute__((__nonnull__));
int read_next_chunk_from_disk(File fd)
__attribute__((__nonnull__, __warn_unused_result__));
int read_rec(rocksdb::Slice* const key, rocksdb::Slice* const val)
__attribute__((__nonnull__, __warn_unused_result__));
int read_slice(rocksdb::Slice* const slice, const uchar** block_ptr)
__attribute__((__nonnull__, __warn_unused_result__));
explicit merge_heap_entry(const rocksdb::Comparator* const comparator) :
chunk_info(nullptr), block(nullptr), comparator(comparator) {}
};
struct merge_heap_comparator
{
bool operator() (const std::shared_ptr<merge_heap_entry>& lhs,
const std::shared_ptr<merge_heap_entry>& rhs)
{
return lhs->comparator->Compare(rhs->key, lhs->key) < 0;
}
};
/* Represents a record in unsorted buffer */
struct merge_record
{
uchar* block; /* points to offset of key in sort buffer */
const rocksdb::Comparator* const comparator;
bool operator< (const merge_record &record) const
{
return merge_record_compare(this->block, record.block, comparator) < 0;
}
merge_record(uchar* const block,
const rocksdb::Comparator* const comparator) :
block(block), comparator(comparator) {}
};
private:
const char* m_tmpfile_path;
const ulonglong m_merge_buf_size;
const ulonglong m_merge_combine_read_size;
const rocksdb::Comparator* m_comparator;
struct merge_file_info m_merge_file;
std::shared_ptr<merge_buf_info> m_rec_buf_unsorted;
std::shared_ptr<merge_buf_info> m_output_buf;
std::set<merge_record> m_offset_tree;
std::priority_queue<std::shared_ptr<merge_heap_entry>,
std::vector<std::shared_ptr<merge_heap_entry>>,
merge_heap_comparator> m_merge_min_heap;
static inline void merge_store_uint64(uchar* const dst, uint64 n)
{
memcpy(dst, &n, sizeof(n));
}
static inline void merge_read_uint64(const uchar **buf_ptr, uint64* const dst)
{
DBUG_ASSERT(buf_ptr != nullptr);
memcpy(dst, *buf_ptr, sizeof(uint64));
*buf_ptr += sizeof(uint64);
}
static inline rocksdb::Slice as_slice(const uchar* block)
{
uint64 len;
merge_read_uint64(&block, &len);
return rocksdb::Slice(reinterpret_cast<const char*>(block), len);
}
static int merge_record_compare(const uchar* a_block, const uchar* b_block,
const rocksdb::Comparator* const comparator)
__attribute__((__nonnull__, __warn_unused_result__));
void merge_read_rec(const uchar* const block, rocksdb::Slice* const key,
rocksdb::Slice* const val)
__attribute__((__nonnull__));
void read_slice(rocksdb::Slice* slice, const uchar* block_ptr)
__attribute__((__nonnull__));
public:
Rdb_index_merge(const char* const tmpfile_path,
const ulonglong &merge_buf_size,
const ulonglong &merge_combine_read_size,
const rocksdb::Comparator* const comparator);
~Rdb_index_merge();
int init()
__attribute__((__nonnull__, __warn_unused_result__));
int merge_file_create()
__attribute__((__nonnull__, __warn_unused_result__));
int add(const rocksdb::Slice& key, const rocksdb::Slice& val)
__attribute__((__nonnull__, __warn_unused_result__));
int merge_buf_write()
__attribute__((__nonnull__, __warn_unused_result__));
int next(rocksdb::Slice* const key, rocksdb::Slice* const val)
__attribute__((__nonnull__, __warn_unused_result__));
int merge_heap_prepare()
__attribute__((__nonnull__, __warn_unused_result__));
void merge_heap_top(rocksdb::Slice* key, rocksdb::Slice* val)
__attribute__((__nonnull__));
int merge_heap_pop_and_get_next(rocksdb::Slice* const key,
rocksdb::Slice* const val)
__attribute__((__nonnull__, __warn_unused_result__));
void merge_reset();
};
} // namespace myrocks
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