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From:Ben Escoto Date:June 3 2001 6:34am
Subject:Bug: mysql uses temp filesort instead of index
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Hi, I think I found a bug in mysql.  I tried the mysqlbug thing but it
didn't work right away.  I hope this message will be detailed enough.
I am not subscribed to the mailing list.

    In the following sections are the output of, respectively:

mysql -e "SHOW VARIABLES"
mysqldump sqmail sequence_data
mysql -e "EXPLAIN SELECT * FROM sqmail.sequence_data WHERE sid = 16
ORDER BY sid desc,id desc LIMIT 10"

The output of the last command contains "Using filesort" when it seems
like it shouldn't.


Variable_name	Value
ansi_mode	OFF
back_log	50
basedir	/usr/
bdb_cache_size	8388600
bdb_log_buffer_size	32768
bdb_home	/var/lib/mysql/
bdb_max_lock	10000
bdb_logdir	
bdb_shared_data	OFF
bdb_tmpdir	/tmp/
bdb_version	Sleepycat Software: Berkeley DB 3.2.9a: (May  9, 2001)
binlog_cache_size	32768
character_set	latin1
character_sets	latin1 big5 cp1251 cp1257 croat czech danish dec8 dos estonia euc_kr gb2312
gbk german1 greek hebrew hp8 hungarian koi8_ru koi8_ukr latin2 latin5 swe7 usa7 win1250
win1251 win1251ukr ujis sjis tis620
concurrent_insert	ON
connect_timeout	5
datadir	/var/lib/mysql/
delay_key_write	ON
delayed_insert_limit	100
delayed_insert_timeout	300
delayed_queue_size	1000
flush	OFF
flush_time	0
have_bdb	YES
have_gemini	NO
have_innodb	NO
have_isam	YES
have_raid	NO
have_ssl	NO
init_file	
interactive_timeout	28800
join_buffer_size	131072
key_buffer_size	8388600
language	/usr/share/mysql/english/
large_files_support	ON
locked_in_memory	OFF
log	OFF
log_update	OFF
log_bin	OFF
log_slave_updates	OFF
long_query_time	10
low_priority_updates	OFF
lower_case_table_names	0
max_allowed_packet	1048576
max_binlog_cache_size	4294967295
max_binlog_size	1073741824
max_connections	100
max_connect_errors	10
max_delayed_threads	20
max_heap_table_size	16777216
max_join_size	4294967295
max_sort_length	1024
max_user_connections	0
max_tmp_tables	32
max_write_lock_count	4294967295
myisam_recover_options	OFF
myisam_max_extra_sort_file_size	256
myisam_max_sort_file_size	2047
myisam_sort_buffer_size	8388608
net_buffer_length	16384
net_read_timeout	30
net_retry_count	10
net_write_timeout	60
open_files_limit	0
pid_file	/var/run/mysqld/mysqld.pid
port	3306
protocol_version	10
record_buffer	131072
query_buffer_size	0
safe_show_database	OFF
server_id	0
skip_locking	ON
skip_networking	OFF
skip_show_database	OFF
slow_launch_time	2
socket	/var/lib/mysql/mysql.sock
sort_buffer	2097144
table_cache	64
table_type	MYISAM
thread_cache_size	0
thread_stack	65536
transaction_isolation	READ-COMMITTED
timezone	PDT
tmp_table_size	1048576
tmpdir	/tmp/
version	3.23.38
wait_timeout	28800

# MySQL dump 8.14
#
# Host: localhost    Database: sqmail
#--------------------------------------------------------
# Server version	3.23.38

#
# Table structure for table 'sequence_data'
#

CREATE TABLE sequence_data (
  sid int(10) unsigned NOT NULL default '0',
  id int(10) unsigned NOT NULL default '0',
  PRIMARY KEY  (sid,id)
) TYPE=MyISAM;

#
# Dumping data for table 'sequence_data'
#

INSERT INTO sequence_data VALUES (1,1);
INSERT INTO sequence_data VALUES (1,2);


table	type	possible_keys	key	key_len	ref	rows	Extra
sequence_data	ref	sidid	sidid	4	const	1	where used; Using index; Using filesort

Thread
Bug: mysql uses temp filesort instead of indexBen Escoto3 Jun
  • Re: Bug: mysql uses temp filesort instead of indexSinisa Milivojevic3 Jun
    • Re: Bug: mysql uses temp filesort instead of indexBen Escoto3 Jun
      • Re: Bug: mysql uses temp filesort instead of indexSinisa Milivojevic3 Jun
        • Re: Bug: mysql uses temp filesort instead of indexBen Escoto3 Jun
          • Re: Bug: mysql uses temp filesort instead of indexJeremy Zawodny3 Jun
          • Re: Bug: mysql uses temp filesort instead of indexSinisa Milivojevic4 Jun
            • Re: Bug: mysql uses temp filesort instead of indexBen Escoto5 Jun
              • Re: Bug: mysql uses temp filesort instead of indexSinisa Milivojevic5 Jun
      • Re: Bug: mysql uses temp filesort instead of indexryc3 Jun
      • Re: Bug: mysql uses temp filesort instead of indexJeremy Zawodny3 Jun