If an option group name is the same as a program name, options in the group apply specifically to that program. For example, the [mysqld] and [mysql] groups apply to the mysqld server and the mysql client program, respectively.
The [client] option group is read by all client programs provided in MySQL distributions (but not by mysqld). To understand how third-party client programs that use the C API can use option files, see the C API documentation at Section 28.7.7.50, “mysql_options()”.
$ sudo apt install traceroute
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
traceroute
0 upgraded, 1 newly installed, 0 to remove and 9 not upgraded.
Need to get 45.4 kB of archives.
After this operation, 152 kB of additional disk space will be used.
Get:1 http://nova.clouds.archive.ubuntu.com/ubuntu bionic/universe amd64 traceroute amd64 1:2.1.0-2 [45.4 kB]
Fetched 45.4 kB in 1s (35.1 kB/s)
Selecting previously unselected package traceroute.
(Reading database ... 175935 files and directories currently installed.)
Preparing to unpack .../traceroute_1%3a2.1.0-2_amd64.deb ...
Unpacking traceroute (1:2.1.0-2) ...
Processing triggers for man-db (2.8.3-2ubuntu0.1) ...
Setting up traceroute (1:2.1.0-2) ...
update-alternatives: using /usr/bin/traceroute.db to provide /usr/bin/traceroute (traceroute) in auto mode
update-alternatives: using /usr/bin/lft.db to provide /usr/bin/lft (lft) in auto mode
update-alternatives: using /usr/bin/traceproto.db to provide /usr/bin/traceproto (traceproto) in auto mode
update-alternatives: using /usr/sbin/tcptraceroute.db to provide /usr/sbin/tcptraceroute (tcptraceroute) in auto mode
すんなり入った
$ traceroute --version
Modern traceroute for Linux, version 2.1.0
Copyright (c) 2016 Dmitry Butskoy, License: GPL v2 or any later
お試しで調査してみる
$ traceroute --icmp blog.pinkumohikan.com
You do not have enough privileges to use this traceroute method.
socket: Operation not permitted
おおん！？ 少ない権限で動くとは何だったのか
$ sudo traceroute --icmp blog.pinkumohikan.com
traceroute to blog.pinkumohikan.com (13.115.18.61), 30 hops max, 60 byte packets
1 xxx.g.tyo1.static.cnode.io (xxx.xxx.xxx.xxx) 0.918 ms 0.988 ms 1.096 ms
2 g-o-4eb-a13-4-v-712.interq.or.jp (157.7.41.129) 6.723 ms 6.833 ms 6.961 ms
3 unused-133-130-013-013.interq.or.jp (133.130.13.13) 0.754 ms 0.855 ms 0.965 ms
4 unused-133-130-012-034.interq.or.jp (133.130.12.34) 0.856 ms 0.965 ms 1.029 ms
5 16509.tyo.equinix.com (203.190.230.53) 0.600 ms 0.604 ms 0.604 ms
6 * * *
7 * * *
8 54.239.52.93 (54.239.52.93) 2.063 ms 1.693 ms 1.560 ms
9 52.95.30.38 (52.95.30.38) 0.560 ms 0.566 ms 0.651 ms
10 * * *
11 * * *
12 * * *
13 52.95.31.55 (52.95.31.55) 2.160 ms 2.135 ms 2.151 ms
14 52.95.31.173 (52.95.31.173) 1.720 ms 1.692 ms 1.691 ms
15 52.95.31.158 (52.95.31.158) 3.173 ms 3.199 ms 3.215 ms
16 52.95.31.72 (52.95.31.72) 2.948 ms 3.509 ms 3.500 ms
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
23 * * *
24 * * *
25 * * *
26 * * *
27 * * *
28 * * *
29 * * *
30 * * *
失敗しとるやんけｗ
ICMPだと無理っぽいけど、TCP SYNを使うモードを見つけたので試してみる
$ sudo traceroute --tcp blog.pinkumohikan.com
traceroute to blog.pinkumohikan.com (13.115.18.61), 30 hops max, 60 byte packets
1 xxx.g.tyo1.static.cnode.io (xxx.xxx.xxx.xxx) 0.910 ms 1.024 ms 1.045 ms
2 g-o-4eb-a13-4-v-712.interq.or.jp (157.7.41.129) 1.107 ms 1.326 ms 1.527 ms
3 unused-133-130-013-013.interq.or.jp (133.130.13.13) 0.614 ms 0.630 ms 0.619 ms
4 unused-133-130-012-034.interq.or.jp (133.130.12.34) 0.774 ms 0.717 ms 0.844 ms
5 16509.tyo.equinix.com (203.190.230.53) 1.041 ms 1.033 ms 1.030 ms
6 * * *
7 * * *
8 54.239.52.89 (54.239.52.89) 1.954 ms 54.239.52.103 (54.239.52.103) 9.649 ms 54.239.52.107 (54.239.52.107) 1.492 ms
9 52.95.30.44 (52.95.30.44) 0.988 ms 52.95.30.48 (52.95.30.48) 0.996 ms 52.95.30.60 (52.95.30.60) 0.870 ms
10 * * *
11 * * *
12 * * *
13 52.95.31.19 (52.95.31.19) 2.169 ms 52.95.31.43 (52.95.31.43) 2.507 ms 52.95.31.47 (52.95.31.47) 2.097 ms
14 52.95.31.221 (52.95.31.221) 2.020 ms 52.95.31.183 (52.95.31.183) 2.802 ms 52.95.31.215 (52.95.31.215) 2.092 ms
15 52.95.31.168 (52.95.31.168) 2.189 ms 52.95.31.188 (52.95.31.188) 4.170 ms 52.95.31.172 (52.95.31.172) 3.172 ms
16 52.95.31.86 (52.95.31.86) 2.249 ms 52.95.31.72 (52.95.31.72) 3.035 ms 2.943 ms
17 27.0.0.158 (27.0.0.158) 2.431 ms * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
23 ec2-13-115-18-61.ap-northeast-1.compute.amazonaws.com (13.115.18.61) 1.688 ms 2.683 ms 2.617 ms
24 ec2-13-115-18-61.ap-northeast-1.compute.amazonaws.com (13.115.18.61) 1.945 ms 2.926 ms 2.171 ms
MySQL 8以降ではオプティマイザがヒストグラム統計というものを考慮するようになったため、mysqldumpもdumpをloadする際にヒストグラム統計をリセットさせる目的でANALYZE TABLE文を自動生成しようとする。そのときinformation_schema.COLUMN_STATISTICSを参照するが、そのテーブルがあるのはMySQL 8.0以降なのでそれ以前のバージョンのMySQLだと怒られが発生する、という具合のようだ。
$ mysqldump --version
mysqldump Ver 8.0.16 for osx10.14 on x86_64 (Homebrew)
$ mysqldump --help
...
--column-statistics Add an ANALYZE TABLE statement to regenerate any existing
column statistics.
(Defaults to on; use --skip-column-statistics to disable.)
...
テーブル統計情報のヒストグラム
MySQL 8.0では、オプティマイザがテーブル統計情報のヒストグラムを活用できるようになった。WHERE句の条件にマッチする行が、テーブルスキャンによってどの程度に絞り込まれるかということを見積もることによって、敢えてスキャンを選ぶべきかどうかが分かる。リアルタイム性が高い処理ではインデックスをバッチリ使用するように最適化することが多いのでヒストグラムの出番は無いだろうが、分析系の処理では重宝することもあるだろう。
