91 lines
3.1 KiB
C++
91 lines
3.1 KiB
C++
/* Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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#ifndef UNIQUES_INCLUDED
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#define UNIQUES_INCLUDED
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#include "my_tree.h" // TREE
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#include "prealloced_array.h" // Prealloced_array
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#include "sql_alloc.h" // Sql_alloc
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class Cost_model_table;
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/*
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Unique -- class for unique (removing of duplicates).
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Puts all values to the TREE. If the tree becomes too big,
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it's dumped to the file. User can request sorted values, or
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just iterate through them. In the last case tree merging is performed in
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memory simultaneously with iteration, so it should be ~2-3x faster.
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*/
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class Unique :public Sql_alloc
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{
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Prealloced_array<Merge_chunk, 16, true> file_ptrs;
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ulong max_elements;
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ulonglong max_in_memory_size;
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IO_CACHE file;
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TREE tree;
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uchar *record_pointers;
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bool flush();
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uint size;
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public:
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ulong elements;
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Unique(qsort_cmp2 comp_func, void *comp_func_fixed_arg,
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uint size_arg, ulonglong max_in_memory_size_arg);
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~Unique();
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ulong elements_in_tree() { return tree.elements_in_tree; }
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inline bool unique_add(void *ptr)
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{
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DBUG_ENTER("unique_add");
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DBUG_PRINT("info", ("tree %u - %lu", tree.elements_in_tree, max_elements));
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if (tree.elements_in_tree > max_elements && flush())
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DBUG_RETURN(1);
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DBUG_RETURN(!tree_insert(&tree, ptr, 0, tree.custom_arg));
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}
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bool get(TABLE *table);
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typedef Bounds_checked_array<uint> Imerge_cost_buf_type;
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static double get_use_cost(Imerge_cost_buf_type buffer,
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uint nkeys, uint key_size,
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ulonglong max_in_memory_size,
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const Cost_model_table *cost_model);
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// Returns the number of elements needed in Imerge_cost_buf_type.
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inline static size_t get_cost_calc_buff_size(ulong nkeys, uint key_size,
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ulonglong max_in_memory_size)
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{
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ulonglong max_elems_in_tree=
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(max_in_memory_size / ALIGN_SIZE(sizeof(TREE_ELEMENT)+key_size));
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return 1 + static_cast<size_t>(nkeys/max_elems_in_tree);
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}
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void reset();
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bool walk(tree_walk_action action, void *walk_action_arg);
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uint get_size() const { return size; }
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ulonglong get_max_in_memory_size() const { return max_in_memory_size; }
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friend int unique_write_to_file(uchar* key, element_count count, Unique *unique);
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friend int unique_write_to_ptrs(uchar* key, element_count count, Unique *unique);
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};
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#endif // UNIQUES_INCLUDED
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