mariadb/sql/sql_analyze_stmt.cc
Varun Gupta b753ac066b MDEV-21580: Allow packed sort keys in sort buffer
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.
2020-03-10 15:09:17 +05:30

122 lines
3.3 KiB
C++

/*
Copyright (c) 2015 MariaDB Corporation Ab
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 02110-1335 USA */
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#include "mariadb.h"
#include "sql_priv.h"
#include "sql_select.h"
#include "my_json_writer.h"
void Filesort_tracker::print_json_members(Json_writer *writer)
{
const char *varied_str= "(varied across executions)";
String str;
if (!get_r_loops())
writer->add_member("r_loops").add_null();
else
writer->add_member("r_loops").add_ll(get_r_loops());
if (get_r_loops() && time_tracker.timed)
{
writer->add_member("r_total_time_ms").
add_double(time_tracker.get_time_ms());
}
if (r_limit != HA_POS_ERROR)
{
writer->add_member("r_limit");
if (!get_r_loops())
writer->add_null();
else if (r_limit == 0)
writer->add_str(varied_str);
else
writer->add_ll(r_limit);
}
writer->add_member("r_used_priority_queue");
if (!get_r_loops())
writer->add_null();
else if (r_used_pq == get_r_loops())
writer->add_bool(true);
else if (r_used_pq == 0)
writer->add_bool(false);
else
writer->add_str(varied_str);
if (!get_r_loops())
writer->add_member("r_output_rows").add_null();
else
writer->add_member("r_output_rows").add_ll(
(longlong) rint((double)r_output_rows / get_r_loops()));
if (sort_passes)
{
writer->add_member("r_sort_passes").add_ll(
(longlong) rint((double)sort_passes / get_r_loops()));
}
if (sort_buffer_size != 0)
{
writer->add_member("r_buffer_size");
if (sort_buffer_size == ulonglong(-1))
writer->add_str(varied_str);
else
writer->add_size(sort_buffer_size);
}
get_data_format(&str);
writer->add_member("r_sort_mode").add_str(str.c_ptr(), str.length());
}
void Filesort_tracker::get_data_format(String *str)
{
if (r_sort_keys_packed)
str->append("packed_sort_key");
else
str->append("sort_key");
str->append(",");
if (r_using_addons)
{
if (r_packed_addon_fields)
str->append("packed_addon_fields");
else
str->append("addon_fields");
}
else
str->append("rowid");
}
void attach_gap_time_tracker(THD *thd, Gap_time_tracker *gap_tracker,
ulonglong timeval)
{
thd->gap_tracker_data.bill_to= gap_tracker;
thd->gap_tracker_data.start_time= timeval;
}
void process_gap_time_tracker(THD *thd, ulonglong timeval)
{
if (thd->gap_tracker_data.bill_to)
{
thd->gap_tracker_data.bill_to->log_time(thd->gap_tracker_data.start_time,
timeval);
thd->gap_tracker_data.bill_to= NULL;
}
}