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476b24d084
SELECT DISTINCT did not work with expressions with sum functions. Distinct was only done on the values stored in the intermediate temporary tables, which only stored the value of each sum function. In other words: SELECT DISTINCT sum(a),sum(b),avg(c) ... worked. SELECT DISTINCT sum(a),sum(b) > 2,sum(c)+sum(d) would not work. The later query would do ONLY apply distinct on the sum(a) part. Reviewer: Sergei Petrunia <sergey@mariadb.com> This was fixed by extending remove_dup_with_hash_index() and remove_dup_with_compare() to take into account the columns in the result list that where not stored in the temporary table. Note that in many cases the above dup removal functions are not used as the optimizer may be able to either remove duplicates early or it will discover that duplicate remove is not needed. The later happens for example if the group by fields is part of the result. Other things: - Backported from 11.0 the change of Sort_param.tmp_buffer from char* to String. - Changed Type_handler::make_sort_key() to take String as a parameter instead of Sort_param. This was done to allow make_sort_key() functions to be reused by distinct elimination functions. This makes Type_handler_string_result::make_sort_key() similar to code in 11.0 - Simplied error handling in remove_dup_with_compare() to remove code duplication.
120 lines
4.3 KiB
C++
120 lines
4.3 KiB
C++
#ifndef SQL_SORT_INCLUDED
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#define SQL_SORT_INCLUDED
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/* Copyright (c) 2000, 2010, 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 02110-1335 USA */
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#include "my_base.h" /* ha_rows */
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#include <my_sys.h> /* qsort2_cmp */
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#include "queues.h"
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#include "sql_string.h"
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typedef struct st_buffpek BUFFPEK;
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struct SORT_FIELD;
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class Field;
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struct TABLE;
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/* Defines used by filesort and uniques */
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#define MERGEBUFF 7
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#define MERGEBUFF2 15
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/*
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The structure SORT_ADDON_FIELD describes a fixed layout
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for field values appended to sorted values in records to be sorted
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in the sort buffer.
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Only fixed layout is supported now.
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Null bit maps for the appended values is placed before the values
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themselves. Offsets are from the last sorted field, that is from the
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record referefence, which is still last component of sorted records.
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It is preserved for backward compatiblility.
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The structure is used tp store values of the additional fields
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in the sort buffer. It is used also when these values are read
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from a temporary file/buffer. As the reading procedures are beyond the
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scope of the 'filesort' code the values have to be retrieved via
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the callback function 'unpack_addon_fields'.
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*/
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typedef struct st_sort_addon_field
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{
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/* Sort addon packed field */
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Field *field; /* Original field */
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uint offset; /* Offset from the last sorted field */
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uint null_offset; /* Offset to to null bit from the last sorted field */
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uint length; /* Length in the sort buffer */
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uint8 null_bit; /* Null bit mask for the field */
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} SORT_ADDON_FIELD;
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struct BUFFPEK_COMPARE_CONTEXT
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{
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qsort_cmp2 key_compare;
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void *key_compare_arg;
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};
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class Sort_param {
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public:
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uint rec_length; // Length of sorted records.
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uint sort_length; // Length of sorted columns.
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uint ref_length; // Length of record ref.
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uint res_length; // Length of records in final sorted file/buffer.
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uint max_keys_per_buffer; // Max keys / buffer.
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uint min_dupl_count;
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ha_rows max_rows; // Select limit, or HA_POS_ERROR if unlimited.
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ha_rows examined_rows; // Number of examined rows.
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TABLE *sort_form; // For quicker make_sortkey.
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SORT_FIELD *local_sortorder;
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SORT_FIELD *end;
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SORT_ADDON_FIELD *addon_field; // Descriptors for companion fields.
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LEX_STRING addon_buf; // Buffer & length of added packed fields.
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uchar *unique_buff;
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bool not_killable;
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String tmp_buffer;
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// The fields below are used only by Unique class.
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qsort2_cmp compare;
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BUFFPEK_COMPARE_CONTEXT cmp_context;
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Sort_param()
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{
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memset(reinterpret_cast<void*>(this), 0, sizeof(*this));
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tmp_buffer.set_thread_specific();
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/*
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Fix memset() clearing the charset.
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TODO: The constructor should be eventually rewritten not to use memset().
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*/
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tmp_buffer.set_charset(&my_charset_bin);
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}
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void init_for_filesort(uint sortlen, TABLE *table,
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ha_rows maxrows, bool sort_positions);
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};
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int merge_many_buff(Sort_param *param, uchar *sort_buffer,
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BUFFPEK *buffpek,
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uint *maxbuffer, IO_CACHE *t_file);
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ulong read_to_buffer(IO_CACHE *fromfile,BUFFPEK *buffpek,
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uint sort_length);
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bool merge_buffers(Sort_param *param,IO_CACHE *from_file,
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IO_CACHE *to_file, uchar *sort_buffer,
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BUFFPEK *lastbuff,BUFFPEK *Fb,
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BUFFPEK *Tb,int flag);
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int merge_index(Sort_param *param, uchar *sort_buffer,
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BUFFPEK *buffpek, uint maxbuffer,
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IO_CACHE *tempfile, IO_CACHE *outfile);
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void reuse_freed_buff(QUEUE *queue, BUFFPEK *reuse, uint key_length);
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#endif /* SQL_SORT_INCLUDED */
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