There are several options to implement firewall like features for a MySQL instance. Some of these are described below. When an account is mentioned it refers to the combination of a username connected from a given host, i.e. username@hostname. MySQL Enterprise Firewall MySQL Enterprise Firewall will allow you to create a whitelist per account specifying the normalized queries that the account are allowed to execute. It is available in the Enterprise Edition of MySQL Server in versions … [Read more...] about MySQL – How to Set Maximum Rates for Connections and Queries
How to configure EPEL repository in OEL 7
Question: How to install/get packages from EPEL Repository on OEL 7? 1. Create a repo file like /etc/yum/repos.d/epel-yum-ol7.repo. For example: # cat /etc/yum.repos.d/epel-yum-ol7.repo [ol7_epel] name=Oracle Linux $releasever EPEL ($basearch) baseurl=http://yum.oracle.com/repo/OracleLinux/OL7/developer_EPEL/$basearch/ gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle gpgcheck=1 enabled=1 2. And then run "yum repolist" command to see if repository is in there. # yum … [Read more...] about How to configure EPEL repository in OEL 7
MySQL: How to Set Account Resource Limits
Limit the use of server resources by setting the global MAX_USER_CONNECTIONS variable to a non-zero value. This limits the number of simultaneous connections by any one account but does not limit what a client can do when connected. To set resource limits for an account, use the GRANT statement with a WITH clause that names each resource to be limited. The default value for each limit is zero, indicating no limit. For example, to set limits for user Francis to access the customer database, issue … [Read more...] about MySQL: How to Set Account Resource Limits
MySQL ‘show processlist’ statement
You can also get thread information from the INFORMATION_SCHEMA.PROCESSLIST table or the mysqladmin processlist command. If you do not have the PROCESS privilege, you can view only your own threads. That is, you can view only those threads associated with the MySQL account that you are using. If you do not use the FULL keyword, only the first 100 characters of each statement are shown in the Info field. I am on a test MySQL database and currently, no process is running on it. On a busy … [Read more...] about MySQL ‘show processlist’ statement
Understanding the REVOKE statement in MySQL
The REVOKE command is used to rescind privileges previously granted to a user. Its syntax is: REVOKE priv_type [(column_list)] [, priv_type [(column_list)] ...] ON {tbl_name | * | *.* | db_name.*} FROM user_name [, user_name ...] As is the case with the GRANT command, perhaps the best way to really understand how it operates is to experiment with several examples. Assume that the administrator wants to repeal the DELETE privilege from the user widgetAdmin. This is … [Read more...] about Understanding the REVOKE statement in MySQL
MySQL Grants – Setting User Permissions On Different Tables
Question: How to set a user, read-only permission for few tables, and alter/insert/delete permission for the rest of the tables? This can be achieved using MySQL grant's, as MySQL do allow to allow/revoke privileges at a table level. Normally, a database administrator first uses CREATE USER to create an account, then GRANT to define its privileges and characteristics. For example: CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'password'; GRANT ALL ON db1.* TO 'jeffrey'@'localhost'; GRANT … [Read more...] about MySQL Grants – Setting User Permissions On Different Tables
Excluding a table or database from MySQL replication
This post discusses how to use replication filters to ignore a table or a database in replication. MySQL both have replication filters that explicitly allows and excludes replication of a database or a table from replicating. In this case, you will need to use the filters that ignore. There are three replications filters that can be used to ignore one or more tables: replicate-ignore-db replicate-ignore-table replicate-wild-ignore-table Each of these options will be discussed below. … [Read more...] about Excluding a table or database from MySQL replication
How to re-create the yum cache (force a fetch of the cache data) from enabled repositories in CentOS/RHEL
This post briefly outlines how it possible to re-create the yum cache, or said in another way, force a fetch of the cache data from the enabled yum repositories. The enabled yum repositories are the ones in the following file /etc/yum.conf or in the following folder /etc/yum.repos.d that have their "enabled" setting to "1", e.g. : # vi /etc/yum.repos.d/test.repo [test_repo] name=Test … [Read more...] about How to re-create the yum cache (force a fetch of the cache data) from enabled repositories in CentOS/RHEL
How to Create yum Repository in CentOS/RHEL
1. Create a directory for you local repository, e.g. /home/mypackage_dir/repository. Move the RPMs into that directory. # mkdir /home/mypackage_dir/repository # cp /media/packages/* /home/mypackage_dir/repo 2. Fix some ownership and filesystem permissions: # chown -R root:root /home/mypackage_dir/repo 3. Install the createrepo package if not installed yet, and run: # createrepo /home/mypackage_dir/repo # chmod -R o-w+r /home/mypackage_dir/repo 4. Create a repository configuration … [Read more...] about How to Create yum Repository in CentOS/RHEL
Granting All Privileges On All databases Except One Specific Table in MySQL
The post discusses a useful method to grant all privileges on all databases except one specific table to a user. MySQL does not support granting all privileges on all databases to a user then revoking all privileges on a specific table from that user. This produces an error saying there was no grant rule for the specific table. For example: mysql> CREATE DATABASE testdb; Query OK, 1 row affected (0.80 sec) mysql> CREATE TABLE testdb.testtable (i int); Query OK, 0 rows affected (0.99 … [Read more...] about Granting All Privileges On All databases Except One Specific Table in MySQL