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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., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA */
#pragma once
/* MySQL header files */
#include "../sql/log.h"
#include "./handler.h" /* handler */
#include "./my_global.h" /* ulonglong */
/* C++ standard header files */
#include <queue>
#include <set>
#include <vector>
/* 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 m_fd = -1; /* file descriptor */
ulong m_num_sort_buffers = 0; /* 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[]> m_block;
const ulonglong
m_block_len; /* amount of data bytes allocated for block above */
ulonglong m_curr_offset; /* offset of the record pointer for the block */
ulonglong m_disk_start_offset; /* where the chunk starts on disk */
ulonglong m_disk_curr_offset; /* current offset on disk */
ulonglong m_total_size; /* total # of data bytes in chunk */
void store_key_value(const rocksdb::Slice &key, const rocksdb::Slice &val)
MY_ATTRIBUTE((__nonnull__));
void store_slice(const rocksdb::Slice &slice) MY_ATTRIBUTE((__nonnull__));
size_t prepare(File fd, ulonglong f_offset) MY_ATTRIBUTE((__nonnull__));
int read_next_chunk_from_disk(File fd)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
inline bool is_chunk_finished() const {
return m_curr_offset + m_disk_curr_offset - m_disk_start_offset ==
m_total_size;
}
inline bool has_space(uint64 needed) const {
return m_curr_offset + needed <= m_block_len;
}
explicit merge_buf_info(const ulonglong merge_block_size)
: m_block(nullptr),
m_block_len(merge_block_size),
m_curr_offset(0),
m_disk_start_offset(0),
m_disk_curr_offset(0),
m_total_size(merge_block_size) {
/* Will throw an exception if it runs out of memory here */
m_block = std::unique_ptr<uchar[]>(new uchar[merge_block_size]);
/* Initialize entire buffer to 0 to avoid valgrind errors */
memset(m_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> m_chunk_info; /* pointer to buffer info */
uchar *m_block; /* pointer to heap memory where record is stored */
const rocksdb::Comparator *const m_comparator;
rocksdb::Slice m_key; /* current key pointed to by block ptr */
rocksdb::Slice m_val;
size_t prepare(File fd, ulonglong f_offset, ulonglong chunk_size)
MY_ATTRIBUTE((__nonnull__));
int read_next_chunk_from_disk(File fd)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
int read_rec(rocksdb::Slice *const key, rocksdb::Slice *const val)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
int read_slice(rocksdb::Slice *const slice, const uchar **block_ptr)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
explicit merge_heap_entry(const rocksdb::Comparator *const comparator)
: m_chunk_info(nullptr), m_block(nullptr), m_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->m_comparator->Compare(rhs->m_key, lhs->m_key) < 0;
}
};
/* Represents a record in unsorted buffer */
struct merge_record {
uchar *m_block; /* points to offset of key in sort buffer */
const rocksdb::Comparator *const m_comparator;
bool operator<(const merge_record &record) const {
return merge_record_compare(this->m_block, record.m_block, m_comparator) <
0;
}
merge_record(uchar *const block,
const rocksdb::Comparator *const comparator)
: m_block(block), m_comparator(comparator) {}
};
private:
const char *m_tmpfile_path;
const ulonglong m_merge_buf_size;
const ulonglong m_merge_combine_read_size;
const ulonglong m_merge_tmp_file_removal_delay;
rocksdb::ColumnFamilyHandle *m_cf_handle;
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)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
void merge_read_rec(const uchar *const block, rocksdb::Slice *const key,
rocksdb::Slice *const val) MY_ATTRIBUTE((__nonnull__));
void read_slice(rocksdb::Slice *slice, const uchar *block_ptr)
MY_ATTRIBUTE((__nonnull__));
public:
Rdb_index_merge(const char *const tmpfile_path,
const ulonglong merge_buf_size,
const ulonglong merge_combine_read_size,
const ulonglong merge_tmp_file_removal_delay,
rocksdb::ColumnFamilyHandle *cf);
~Rdb_index_merge();
int init() MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
int merge_file_create() MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
int add(const rocksdb::Slice &key, const rocksdb::Slice &val)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
int merge_buf_write() MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
int next(rocksdb::Slice *const key, rocksdb::Slice *const val)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
int merge_heap_prepare() MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
void merge_heap_top(rocksdb::Slice *key, rocksdb::Slice *val)
MY_ATTRIBUTE((__nonnull__));
int merge_heap_pop_and_get_next(rocksdb::Slice *const key,
rocksdb::Slice *const val)
MY_ATTRIBUTE((__nonnull__, __warn_unused_result__));
void merge_reset();
rocksdb::ColumnFamilyHandle *get_cf() const { return m_cf_handle; }
};
} // namespace myrocks
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