uniques.cc File Reference

#include "sql/uniques.h"
#include <string.h>
#include <algorithm>
#include <atomic>
#include <cmath>
#include <vector>
#include "my_base.h"
#include "my_compiler.h"
#include "my_dbug.h"
#include "my_io.h"
#include "my_tree.h"
#include "mysql/components/services/bits/psi_bits.h"
#include "mysql/psi/mysql_file.h"
#include "mysql/service_mysql_alloc.h"
#include "priority_queue.h"
#include "sql/field.h"
#include "sql/handler.h"
#include "sql/malloc_allocator.h"
#include "sql/merge_many_buff.h"
#include "sql/mysqld.h"
#include "sql/opt_costmodel.h"
#include "sql/psi_memory_key.h"
#include "sql/sql_base.h"
#include "sql/sql_class.h"
#include "sql/sql_const.h"
#include "sql/sql_executor.h"
#include "sql/sql_sort.h"
#include "sql/sql_tmp_table.h"
#include "sql/table.h"

Classes
struct	anonymous_namespace{uniques.cc}::Merge_chunk_compare_context
class	anonymous_namespace{uniques.cc}::Uniq_param
struct	anonymous_namespace{uniques.cc}::Merge_chunk_less

Namespaces
namespace	anonymous_namespace{uniques.cc}

Functions
static uint	uniq_read_to_buffer (IO_CACHE *fromfile, Merge_chunk *merge_chunk, Uniq_param *param)
	Read data to buffer. More...
static int	merge_buffers (THD *thd, Uniq_param *param, IO_CACHE *from_file, IO_CACHE *to_file, Sort_buffer sort_buffer, Merge_chunk *last_chunk, Merge_chunk_array chunk_array, int flag)
	Merge buffers to one buffer. More...
int	unique_write_to_file (void *v_key, element_count, void *v_unique)
int	unique_write_to_ptrs (void *v_key, element_count, void *v_unique)
static double	log2_n_fact (ulong n)
	Calculate log2(n!) More...
static double	get_merge_buffers_cost (size_t total_buf_elems, size_t n_buffers, uint elem_size, const Cost_model_table *cost_model)
static double	get_merge_many_buffs_cost (uint num_full_buffers, uint elems_per_buffer, uint additional_num_elems, int elem_size, const Cost_model_table *cost_model)
static int	merge_chunk_compare (Merge_chunk_compare_context *ctx, uchar *key_ptr1, uchar *key_ptr2)
static bool	merge_walk (uchar *merge_buffer, size_t merge_buffer_size, size_t key_length, Merge_chunk *begin, Merge_chunk *end, tree_walk_action walk_action, void *walk_action_arg, qsort2_cmp compare, const void *compare_arg, IO_CACHE *file)

Function Documentation

get_merge_buffers_cost()

static double get_merge_buffers_cost ( size_t  total_buf_elems, size_t  n_buffers, uint  elem_size, const Cost_model_table *  cost_model  )

static

get_merge_many_buffs_cost()

static double get_merge_many_buffs_cost ( uint  num_full_buffers, uint  elems_per_buffer, uint  additional_num_elems, int  elem_size, const Cost_model_table *  cost_model  )

static

log2_n_fact()

static double log2_n_fact ( ulong  n )

inlinestatic

Calculate log2(n!)

Stirling's approximate formula is used:

n! ~= sqrt(2*M_PI*n) * (n/M_E)^n

Derivation of formula used for calculations is as follows:

log2(n!) = log2(sqrt(2*M_PI*n)*(n/M_E)^n)

= log2(2*M_PI*n)/2 + n*log2(n/M_E)

= log2(2*M_PI)/2 + log2(n)/2 + n * (log2(n) - M_LOG2E);

Parameters

n	the number to calculate log2(n!) for

Returns

log2(n!) for the function argument

merge_buffers()

static int merge_buffers ( THD *  thd, Uniq_param *  param, IO_CACHE *  from_file, IO_CACHE *  to_file, Sort_buffer  sort_buffer, Merge_chunk *  last_chunk, Merge_chunk_array  chunk_array, int  flag  )

static

Merge buffers to one buffer.

Parameters

	thd	thread context
	param	Sort parameter
	from_file	File with source data (Merge_chunks point to this file)
	to_file	File to write the sorted result data.
	sort_buffer	Buffer for data to store up to MERGEBUFF2 sort keys.
[out]	last_chunk	Store here Merge_chunk describing data written to to_file.
	chunk_array	Array of chunks to merge.
	flag	0 - write full record, 1 - write addon/ref

Return values

0	OK
other	error

merge_chunk_compare()

static int merge_chunk_compare ( Merge_chunk_compare_context *  ctx, uchar *  key_ptr1, uchar *  key_ptr2  )

static

merge_walk()

static bool merge_walk ( uchar *  merge_buffer, size_t  merge_buffer_size, size_t  key_length, Merge_chunk *  begin, Merge_chunk *  end, tree_walk_action  walk_action, void *  walk_action_arg, qsort2_cmp  compare, const void *  compare_arg, IO_CACHE *  file  )

static

uniq_read_to_buffer()

static uint uniq_read_to_buffer ( IO_CACHE *  fromfile, Merge_chunk *  merge_chunk, Uniq_param *  param  )

static

Read data to buffer.

Returns

(uint)-1 if something goes wrong

unique_write_to_file()

int unique_write_to_file	(	void *	v_key,
		element_count	count,
		void *	v_unique
	)

unique_write_to_ptrs()

int unique_write_to_ptrs	(	void *	v_key,
		element_count	count,
		void *	v_unique
	)