php_network_getaddresses: getaddrinfo failed: Name or service not known
PHP connects to alicycle RDS version database. At the beginning, the project domain name is configured. After the resolution is successful, the access is
that cannot be connected to the database
the solution is to restart the PHP service
service php-fpm restart
connect successfully after restart
installation package: mysql-workbench-community-8.0.18-winx64. Msi
version no. : MySQL Workbench 8.0 CE
connection tip:
tried
1. Neither localhost nor ::1
2. Query whether host exists under user, -> Invalid
3. Add
bind-address = 127.0.0.1
“
” under [mysqld] in my. Navicat and hedisql can both connect
finally found a solution in bug-75745: due to the high version of the incompatible, download version 6.3.10 at the workbench download address to install
why do you want to use MySQL Workbench?Because you need to switch databases in multiple environments in your work, so after using heidisql(GPL open source) and navicat(charged), I tried a wave of MySQL Workbench(Community GPL open source) and found that there are multiple tabs to switch multiple environment databases, which can be used. If you are used to heidisql and navicat, you can use them without changing
ALTER TABLE `table_name` AUTO_INCREMENT = 1mysql, error reported: 1822-failed to add the foreign key constraint. Missing index for constraint ‘tb_emp_ibfk_1’ in the referenced table ‘tb_dept’
reason: if table A has no primary key set, the fields in table A cannot be used as foreign keys for table B.
solution, on the premise of not deleting table A, add the following SQL text:
SQL:
DROP DATABASE IF EXISTS tb_test;
CREATE DATABASE tb_test DEFAULT charset utf8;
USE tb_test;
# 部门表
CREATE TABLE tb_dept (
deptno INT NOT NULL COMMENT '编号',
deptname VARCHAR ( 10 ) NOT NULL COMMENT '名称',
deptaddr VARCHAR ( 20 ) NOT NULL COMMENT '地址'
);
INSERT INTO tb_dept VALUES
( 101, '研发部门', '武汉' ),
( 127, '会计部门', '上海' );
# 员工表
DROP TABLE IF EXISTS tb_emp;
CREATE TABLE tb_emp (
empno INT NOT NULL COMMENT '编号',
empname VARCHAR ( 10 ) NOT NULL COMMENT '姓名',
empjob VARCHAR ( 10 ) NOT NULL COMMENT '职位',
empsal INT NOT NULL DEFAULT 3000 COMMENT '薪酬',
deptno INT NOT NULL COMMENT '所属部门',
PRIMARY KEY ( empno ),
FOREIGN KEY ( deptno ) REFERENCES tb_dept ( deptno )
);
INSERT INTO tb_emp VALUES
(10001,'杨过','研发主管',2000000,101),
(40001,'张三丰','总裁',90000000,127);operation result:
DROP DATABASE IF EXISTS tb_test
> OK
> 时间: 0.32s
CREATE DATABASE tb_test DEFAULT charset utf8
> OK
> 时间: 0.991s
USE tb_test
> OK
> 时间: 0.008s
# 部门表
CREATE TABLE tb_dept (
deptno INT NOT NULL COMMENT '编号',
deptname VARCHAR ( 10 ) NOT NULL COMMENT '名称',
deptaddr VARCHAR ( 20 ) NOT NULL COMMENT '地址'
)
> OK
> 时间: 1.74s
INSERT INTO tb_dept VALUES
( 101, '研发部门', '武汉' ),
( 127, '会计部门', '上海' )
> Affected rows: 2
> 时间: 0.532s
# 员工表
DROP TABLE IF EXISTS tb_emp
> OK
> 时间: 0.393s
CREATE TABLE tb_emp (
empno INT NOT NULL COMMENT '编号',
empname VARCHAR ( 10 ) NOT NULL COMMENT '姓名',
empjob VARCHAR ( 10 ) NOT NULL COMMENT '职位',
empsal INT NOT NULL DEFAULT 3000 COMMENT '薪酬',
deptno INT NOT NULL COMMENT '所属部门',
PRIMARY KEY ( empno ),
FOREIGN KEY ( deptno ) REFERENCES tb_dept ( deptno )
)
> 1822 - Failed to add the foreign key constraint. Missing index for constraint 'tb_emp_ibfk_1' in the referenced table 'tb_dept'
> 时间: 0.034s
error:
SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known
environment: thinkphp framework, Linux, ali cloud RDS database
ping link address normal:
error reporting process: access the background address, most are normal access, refresh 10-20 times may appear 1-2 error, not continuous error
solution 1:
restart php-fpm service
service php-fpm restart the original view: https://stackoverflow.com/questions/2661546/php-network-getaddresses-getaddrinfo-failed-name-or-service-not-known
special thanks to: https://blog.csdn.net/qq_37500838/article/details/85008432#commentBox
solution 2:
configure DNS resolution to 114.114.114.114
check DNS configuration: cat /etc/resolv.conf
I use the first solution, the second solution is temporarily useless, configuration method can be found on the Internet
create user ‘test’ @’ % ‘identified by’ test ‘;
create user ‘test’ @% ‘identified by’ test ‘;
display ERROR 1396 (HY000): Operation CREATE USER failed for ‘test’ @ ‘%’
check whether there is this USER
select USER from USER;
found no such user.
remember you deleted this user last time.
flush privileges may not be flush;
, ERROR 1396 (HY000): Operation CREATE USER failed for ‘test’ @ ‘%’
drop USER ‘test’ @ ‘%’;
drop USER ‘test’ @ ‘%’;
failed for ‘test’ @ ‘%’;
drop USER ‘test’ @ ‘%’;
flush privileges;
create user ‘test’ @ ‘%’ identified by ‘test’;
create user ‘test’ @ ‘%’ identified by ‘test’;
success.
Assume the user is there, so drop the user
After deleting the user, there is need to flush the mysql privileges
Now create the user.
http://stackoverflow.com/questions/5555328/error-1396-hy000-operation-create-user-failed-for-jacklocalhost
SQL Error: 1054, SQLState: 42S22 this is the Error caused by the missing field, first attach the Error log:
2020-03-04 10:30:00. 221 WARN [pool – 8 – thread – 1] [org. Hibernate. Engine. JDBC. Spi. SqlExceptionHelper. Java: 127] – SQL Error: 1054, SQLState: 42 s22
the 2020-03-04 10:30:00. 221 ERROR [pool – 8 – thread – 1] [org. Hibernate. Engine. JDBC. Spi. SqlExceptionHelper. Java: 129] – Unknown column ‘markcardex0_. Art_service_time’ in ‘field List ‘
the 2020-03-04 10:30:00. 225 ERROR [pool – 8 – thread – 1] [org. Springframework. Scheduling. Support. TaskUtils $LoggingErrorHandler. Java: 95] – Unexpected ERROR occurred in scheduled task.
org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; Nested exception is org. Hibernate. Exception….
…
under Caused by: org. Hibernate. Exception. SQLGrammarException: could not extract the ResultSet
… 24 common frames omitted
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column ‘markcardex0_. Art_service_time’ in ‘the field list’
the at sun, reflect the NativeConstructorAccessorImpl. NewInstance0 (Native Method)
the at Sun. Reflect. NativeConstructorAccessorImpl. NewInstance (NativeConstructorAccessorImpl. Java: 62)
the at Sun. Reflect. DelegatingConstructorAccessorImpl. NewInstance (DelegatingConstructorAccessorImpl. Java: 45)
the at Java lang. Reflect. Constructor. NewInstance (423) Constructor. Java:
the at Com. Mysql. JDBC. Util. HandleNewInstance Util. Java: (411)
at the mysql. JDBC. Util. GetInstance (Util. Java: 386)
at the mysql. JDBC. SQLError. CreateSQLException (SQLError. Java: 1053)
the at Com. Mysql. JDBC. MysqlIO. CheckErrorPacket MysqlIO. Java: (4074)
at the mysql. JDBC. MysqlIO. CheckErrorPacket (MysqlIO. Java: 4006)
at the mysql. JDBC. MysqlIO. SendCommand (MysqlIO. Java: 2468)
At com. Mysql. JDBC. MysqlIO. SqlQueryDirect (MysqlIO. Java: 2629)
at the mysql. JDBC. ConnectionImpl. ExecSQL (ConnectionImpl. Java: 2719)
the at . Com. Mysql. JDBC PreparedStatement. ExecuteInternal (PreparedStatement. Java: 2155)
at the mysql.. JDBC PreparedStatement. ExecuteQuery (2318) a PreparedStatement. Java:
the at Com. Alibaba. Druid. Filter. FilterChainImpl. PreparedStatement_executeQuery (FilterChainImpl. Java: 2714)
the at Com. Alibaba. Druid. Filter. FilterEventAdapter. PreparedStatement_executeQuery (FilterEventAdapter. Java: 465)
the at Com. Alibaba. Druid. Filter. FilterChainImpl. PreparedStatement_executeQuery (FilterChainImpl. Java: 2711)
the at Com. Alibaba. Druid. Proxy. JDBC. PreparedStatementProxyImpl. ExecuteQuery (PreparedStatementProxyImpl. Java: 145)
the at Com. Alibaba. Druid. Pool. DruidPooledPreparedStatement. ExecuteQuery (DruidPooledPreparedStatement. Java: 227)
the at Org. Hibernate. Engine. JDBC. Internal. ResultSetReturnImpl. Extract (ResultSetReturnImpl. Java: 70)
… 60 common frames omitted
error occurs mainly because the variables in the entity class do not match the classes in the database table, which is a headache, especially when the data is complex. I used to be stupid, one by one, but now I can sum up a simple method:
1. Look at the reason for this error: Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column ‘markcardex0_. Art_service_time ‘in ‘field List’ is Unknown column ‘markcardex0_. Art_service_time ‘in ‘field list’ is Unknown column’ mark_service_time ‘in ‘field list’ Find –> Find In Path) quickly search artServiceTime, Find the entity class that defines the variable artServiceTime, click In, as follows:
2. After entering the entity class corresponding to this variable, you can see the database Table corresponding to this entity through the annotation @table (name = “uk_markcard_xxxx”) :
opens the database and verifies the existence of this attribute in the table through the query, as follows:
as shown in the figure above, we found the same error as the console, at this time we add the corresponding entity variable property on the table, note:
(1) attribute type must be the same as the entity variable type
(2) MySQL makes no case difference, but if the variable in the entity class is named aaaBcc, the attribute name in the database should be aaa_bcc, not
operating environment: windows10
database version: mysql.8.0.16
problem description:
MySQL service is starting.
MySQL service cannot start. The
service did not report any errors.
solution:
the MYSQL error, Failed to find valid data directory. _Nikita – _failed CSDN blog to find valid data directory.
https://blog.csdn.net/Hellen0708/article/details/93377724
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the mysql database password _qq_26486949 blog blog – CSDN _mysql password
https://blog.csdn.net/qq_26486949/article/details/88373487
mysql newly installed does not have a password by default, so it needs to be set manually.
method 1: use the SET PASSWORD command
log in to MySQL first.
format: mysql> Set password for username @localhost = password(‘ new password ‘);
example: mysql> set password for root@localhost = password(‘123’);
method 2: mysqladmin
format: mysqladmin-u username -p old password password new password
example: mysqladmin-uroot-p123456 password 123
method 3: edit user table
directly with UPDATE
log in to MySQL first.
mysql> use mysql;
mysql> update user set password=password(‘123′) where user=’root’ and host=’localhost’;
mysql> flush privileges;
method 4: use the GRANT statement mysql> Grant all on *.* to ‘root’@’localhost’ IDENTIFIED BY ‘your password ‘with grant option; mysql> flush privileges;
method 5: when you forget the root password or initialize the password, you can do this:
Take Windows as an example:
1. Close the running MySQL service.
2. Open a DOS window and go to mysql\bin directory.
3. Enter mysqld –skip-grant-tables enter. Skip-grant-tables means to skip permission table authentication when starting MySQL service.
4. Open another DOS window (because the DOS window is no longer active) and go to the mysql\bin directory.
5. Enter mysql enter. If successful, mysql prompt > will appear. .
6. Connection permission database: use mysql; .
. Update user set password=password(“123″) where user=”root”; Don’t forget to put a semicolon at the end.
if ERROR 1054(42S22) Unknown column ‘password’ in ‘field list’ occurs, this is because the password field is no longer available in mysql database in version 5.7, and the password field is changed to authentication_string. The statement should be update User Set Authentication_string =password(“123″) where user=”root”;
7. Flush privileges (mandatory step) : flush privileges; .
8. Quit quit.
9. Log out of the system, enter again, log in with the username root and the new password 123 that you just set.
symptoms:
MySQL master slave copy, when starting slave, the following error occurs:
mysql> start slave;
ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository
solution: check the log,
can see the error, it was not found originally./server246-relay-bin.index file, find the reason, because I used an instance of cold backup file recovery, in mysql library slave_relay_log_info table still retain the previous relay_log information, so it caused to start slave error.
mysql provides tools for deleting records: slave reset;
slave reset does a few things when executed:
1, delete slave_master_info, slave_relay_log_info in both tables; 2. Delete all relay log files and recreate new relay log files; 3, will not change the value of gtid_executed or gtid_purged
mysql> reset slave;
Query OK, 0 rows affected (0.01 sec)
mysql> change master to ......
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
So it’s
so that slave can start.
this problem is in the database connection failure, looked up from the Internet, the solution is varied, there are configuration files, and change the code. But everyone makes the same mistake for different reasons.
will be stupid, suddenly realized that the database can not connect, either url, or a user name or password. Turning back, the real cause was found…
error code:
String url="jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=true";
String username="root";
String password="123456";remove (with warning) or change to false after url:
String url="jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=false";
String username="root";
String password="123456";is not an error, you can query out.
locks the entire database instance. Use the Flush tables with read lock (FTWRL) to keep the entire database read-only, after which the database update statement (add, delete), data definition statement (build, modify table structure), and update class transaction commit statement will be blocked
locks the entire database, so an obvious use case for global locks would be to do a full library logical backup; There is another way to use set global readonly=true to make the entire library read-only, with one big difference:
exception handling, if the client is abnormal to disconnect, MySQL will automatically release the global lock, so that the whole library back to the normal state; After the entire library is set to READOnly, the database will remain readOnly after the exception is disconnected, resulting in the database being unwritable for a long time.
MySQL has two table level locks: table lock and meta data lock (MDL)
table lock syntax lock tables... Read /write, unlock unlock talbes. It is automatically released when the client is disconnected. In addition to restricting the reading and writing of other threads, table locks also restrict the following operation objects of this thread. For example, thread A executes lock tables t1 read,t2 write, while other threads write t1 and read t2 are blocked. Before tables, A thread can only read t1 and write t2
metadata lock is automatically added when accessing a table to ensure that the table structure cannot be modified
when accessing data
MySQL row lock is implemented in each storage engine, InnoDB on the support of row lock, MyISAM engine does not support row lock
row lock is the lock that locks A row of records in the table. When A is processing this row of data and B also wants to process this data, B can only continue
after A has finished processing
two-stage locking protocol
in InnoDB transactions, row locks are added when they are needed, but they are not immediately released when they are not needed, but wait until the current transaction is completed.
so if more than one row needs to be locked in a transaction, put the rows that are most likely to cause concurrency as far back as possible.
an 🌰 :
the ticketing business of a ticketing system is approximately:
customer A ticket, A balance to deduct price
cinema B account balance increase ticket
record transaction log
, the point of concurrency is cinema B to increase revenue. If each customer purchases tickets in the business order of 1, 2, and 3, then concurrent point 2 will hold the lock for a long time. If you change it to 3, 1, or 2 after processing the concurrent points, the row-level lock is released, reducing the wait time for locks between things.
deadlock and deadlock detection
different threads hold each other’s locks, A and B release the lock, B and A release the lock, then deadlock
deadlock treatment strategy:
one strategy is to go straight into the wait until the timeout occurs. This timeout can be set with the parameter innodb_lock_wait_timeout to
to initiate deadlock detection. When a deadlock is found, it will actively roll back a transaction in the death chain bar to allow other transactions to continue execution. The parameter innodb_deadlock_detect is set to on, indicating that this logic is turned on,
. Note here:
(1) deadlock detection is performed only when there is a row lock on the accessed row
(2) not all transactions are scanned for each deadlock detection. For example, at some point, the transaction waiting state is like this:
, B is waiting for A, D is waiting for C, and now there is an E, and it is found that E needs to wait for D, then E will judge whether there will be deadlock with D and C, this detection does not care about B and A
summary: mysql does not support update to return data. Only Postgres is supported.
this is the definition tip, and the return value is an array of Numbers and a Model array.
That means only Postgres plus configuration is supported.
...
/**
* Return the affected rows (only for postgres)
*/
returning?: boolean;
/**
is very angry.