Programmer Think

1, Background introduction The maximum number of connections of PostgreSQL will become a problem that annoys the business at some time. The number of business connections has soared, and the number of connections is full, but the service cannot be restarted. This scenario is very embarrassing. The maximum number of connections can only be rest ...

Introduction: instances equipped with persistent memory (such as re7p, r7p and re6p) provide a large CPU memory ratio. Redis applications running on such instances can greatly reduce the cost of single GiB memory. Taking some operating systems as examples, this paper introduces how to quickly deploy redis applications on such instances.Instance ...

DMDSC setup (VMware virtual machine + Centos7 operating system + DM8x86 version) 1, Construction premise: This setup is applicable to (VMware virtual machine + Centos7 operating system + DM8x86 version): 1. Create shared disk for virtual machine: (steps are as follows) DSC01 node: Create a new virtual disk and remember the name and pa ...

1, Create 1. Create database View the original database of the system mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) Create your own database mysql& ...

[Abstract] as an OLAP database, Clickhouse has very limited support for transactions. This paper mainly introduces how to update and delete Clickhouse data through replacing mergetree. As an OLAP database, Clickhouse has very limited support for transactions. Clickhouse provides the movement operation (through the ALTER TABLE statement) to UPD ...

preface This article is connected to the DSC active standby and standby stand-alone used by Dameng DSC shared cluster Dameng DSC cluster https://blog.csdn.net/qing1122334455/article/details/117935136 1, Planning There are DSC clusters ahead A single machine is prepared here as the standby library Example: pandas is a NumPy based to ...

Database is very important. Without backup, data loss can only run away. So make a backup! 1, Tool introduction mysql dump is a logical backup tool that comes with mysql. Its backup principle is to connect to mysql database through protocol, query the data to be backed up, and convert the queried data into corresponding insert statements. ...

1, Overview of MySQL MMM cluster technology summary: MMM (Master Master replication manager for mysql) is a script program that supports dual master failover and dual master daily management. MMM is developed in Perl and is mainly used to monitor and manage mysql master master replication. It can be said to be mysql master replication mana ...

Spring transaction management simplifies the traditional transaction management process and reduces the workload of developers to a certain extent, because if spring transaction management is not used, programmers have to write programs to deal with it. They need to consider a series of problems such as how to connect with the database and driv ...

catalogue 1, Basic knowledge Establish and close the connection with MySQL server 1) Connect to the specified mysql server 2) Prompt in case of connection error 3) Set default character encoding 4) Select a specific database: mysqli_select_db ( $link , string $dbname); 5) Close the connection with mysql server 2, Realize login registr ...