记一次mysql的问题处理@20181225

需求：由于某种原因，导致一次分库分表的环境中ddl添加字段和索引没有完全成功，比如100个分库，只有部分修改成功，需要将没有修改成功的库和表找出来，在手动去执行。

由于线上环境，这里模拟还原一下该问题的情景。就是有4个database,每个database有2张表，只有部分表上面ddl添加字段成功。

root@lxd-vm1/[(none)] ::>create database db1;
Query OK,  row affected (0.02 sec)

root@lxd-vm1/[(none)] ::>create database db2;
Query OK,  row affected (0.00 sec)

root@lxd-vm1/[(none)] ::>create database db3;
Query OK,  row affected (0.00 sec)

root@lxd-vm1/[(none)] ::>create database db4;
Query OK,  row affected (0.00 sec)

root@lxd-vm1/[(none)] ::>use db1;
Database changed
root@lxd-vm1/[db1] ::>create table t1(id int);
Query OK,  rows affected (0.03 sec)

root@lxd-vm1/[db1] ::>create table t2(id int);
Query OK,  rows affected (0.03 sec)

root@lxd-vm1/[db1] ::>use db2;
Database changed
root@lxd-vm1/[db2] ::>create table t3(id int);
Query OK,  rows affected (0.02 sec)

root@lxd-vm1/[db2] ::>create table t4(id int);
Query OK,  rows affected (0.03 sec)

root@lxd-vm1/[db2] ::>use db3;
Database changed
root@lxd-vm1/[db3] ::>create table t5(id int);
Query OK,  rows affected (0.03 sec)

root@lxd-vm1/[db3] ::>create table t6(id int);
Query OK,  rows affected (0.05 sec)

root@lxd-vm1/[db3] ::>use db4;
Database changed
root@lxd-vm1/[db4] ::>create table t7(id int);
Query OK,  rows affected (0.04 sec)

root@lxd-vm1/[db4] ::>create table t8(id int);
Query OK,  rows affected (0.02 sec)

root@lxd-vm1/[db4] ::>use db3;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
root@lxd-vm1/[db3] ::>alter table t5 add column name varchar();
Query OK,  rows affected (0.06 sec)
Records:   Duplicates:   Warnings: 

root@lxd-vm1/[db3] ::>use db1;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
root@lxd-vm1/[db1] ::>alter table t2 add column name varchar();
Query OK,  rows affected (0.04 sec)
Records:   Duplicates:   Warnings: 

root@lxd-vm1/[db1] ::>

信息确认，只有db1.t2和db3.t5的表上面ddl修改成功了

root@lxd-vm1/[(none)] ::>select distinct table_schema,table_name from information_schema.columns  where column_name='name' and table_schema like 'db%' and table_name like 't%';
+--------------+------------+
| table_schema | table_name |
+--------------+------------+
| db1          | t2         |
| db3          | t5         |
+--------------+------------+
 rows in set (0.00 sec)

问题处理脚本

/opt/mysql5720/bin/mysql -uroot -proot -h5.5.5. -P3306 >/dev/null -Nse "select distinct concat(table_schema,'.',table_name)
from information_schema.columns
where column_name='name'
and table_schema like 'db%'
and table_name like 't%' order by concat(table_schema,'.',table_name) ;" > have.txt

/opt/mysql5720/bin/mysql -uroot -proot -h5.5.5. -P3306 >/dev/null -Nse "select distinct concat(table_schema,'.',table_name)
from information_schema.columns
where table_schema like 'db%'
and table_name like 't%' order by concat(table_schema,'.',table_name);" > all.txt

cat all.txt | while read line
do
    echo $line | grep $line have.txt > /dev/null
    if [[ $? -ne  ]];then
        echo $line >> no.txt
    fi
done

cat no.txt | while read line
do

    /opt/mysql5720/bin/mysql -uroot -proot -h5.5.5. -P3306 >/dev/null -Nse "alter table $line add column name varchar(20);"
    if [[ $? -eq  ]];then
        echo "$line alter successed"
    fi
done
rm -rf all.txt
rm -rf have.txt
rm -rf no.txt

执行上面的脚本

[mysql@lxd-vm1@/home/mysql]$ sh t1.sh
db1.t1 alter successed
db2.t3 alter successed
db2.t4 alter successed
db3.t6 alter successed
db4.t7 alter successed
db4.t8 alter successed

验证，所有的库对应的表上都有需求中的字段：

root@lxd-vm1/[(none)] ::>select distinct table_schema,table_name from information_schema.columns  where column_name='name' and table_schema like 'db%' and table_name like 't%';
+--------------+------------+
| table_schema | table_name |
+--------------+------------+
| db1          | t1         |
| db1          | t2         |
| db2          | t3         |
| db2          | t4         |
| db3          | t5         |
| db3          | t6         |
| db4          | t7         |
| db4          | t8         |
+--------------+------------+
 rows in set (0.00 sec)