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b753ac066b
This task deals with packing the sort key inside the sort buffer, which would
lead to efficient usage of the memory allocated for the sort buffer.
The changes brought by this feature are
1) Sort buffers would have sort keys of variable length
2) The format for sort keys inside the sort buffer would look like
|<sort_length><null_byte><key_part1><null_byte><key_part2>.......|
sort_length is the extra bytes that are required to store the variable
length of a sort key.
3) When packing of sort key is done we store the ORIGINAL VALUES inside
the sort buffer and not the STRXFRM form (mem-comparable sort keys).
4) Special comparison function packed_keys_comparison() is introduced
to compare 2 sort keys.
This patch also contains contributions from Sergei Petrunia.
122 lines
3.3 KiB
C++
122 lines
3.3 KiB
C++
/*
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Copyright (c) 2015 MariaDB Corporation Ab
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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 Street, Fifth Floor, Boston, MA 02110-1335 USA */
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#ifdef USE_PRAGMA_IMPLEMENTATION
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#pragma implementation // gcc: Class implementation
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#endif
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#include "mariadb.h"
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#include "sql_priv.h"
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#include "sql_select.h"
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#include "my_json_writer.h"
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void Filesort_tracker::print_json_members(Json_writer *writer)
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{
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const char *varied_str= "(varied across executions)";
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String str;
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if (!get_r_loops())
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writer->add_member("r_loops").add_null();
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else
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writer->add_member("r_loops").add_ll(get_r_loops());
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if (get_r_loops() && time_tracker.timed)
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{
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writer->add_member("r_total_time_ms").
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add_double(time_tracker.get_time_ms());
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}
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if (r_limit != HA_POS_ERROR)
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{
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writer->add_member("r_limit");
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if (!get_r_loops())
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writer->add_null();
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else if (r_limit == 0)
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writer->add_str(varied_str);
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else
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writer->add_ll(r_limit);
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}
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writer->add_member("r_used_priority_queue");
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if (!get_r_loops())
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writer->add_null();
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else if (r_used_pq == get_r_loops())
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writer->add_bool(true);
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else if (r_used_pq == 0)
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writer->add_bool(false);
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else
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writer->add_str(varied_str);
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if (!get_r_loops())
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writer->add_member("r_output_rows").add_null();
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else
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writer->add_member("r_output_rows").add_ll(
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(longlong) rint((double)r_output_rows / get_r_loops()));
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if (sort_passes)
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{
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writer->add_member("r_sort_passes").add_ll(
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(longlong) rint((double)sort_passes / get_r_loops()));
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}
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if (sort_buffer_size != 0)
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{
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writer->add_member("r_buffer_size");
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if (sort_buffer_size == ulonglong(-1))
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writer->add_str(varied_str);
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else
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writer->add_size(sort_buffer_size);
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}
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get_data_format(&str);
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writer->add_member("r_sort_mode").add_str(str.c_ptr(), str.length());
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}
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void Filesort_tracker::get_data_format(String *str)
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{
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if (r_sort_keys_packed)
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str->append("packed_sort_key");
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else
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str->append("sort_key");
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str->append(",");
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if (r_using_addons)
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{
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if (r_packed_addon_fields)
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str->append("packed_addon_fields");
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else
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str->append("addon_fields");
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}
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else
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str->append("rowid");
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}
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void attach_gap_time_tracker(THD *thd, Gap_time_tracker *gap_tracker,
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ulonglong timeval)
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{
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thd->gap_tracker_data.bill_to= gap_tracker;
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thd->gap_tracker_data.start_time= timeval;
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}
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void process_gap_time_tracker(THD *thd, ulonglong timeval)
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{
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if (thd->gap_tracker_data.bill_to)
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{
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thd->gap_tracker_data.bill_to->log_time(thd->gap_tracker_data.start_time,
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timeval);
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thd->gap_tracker_data.bill_to= NULL;
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}
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}
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