Bucolic Labyrinth

While accessing web configured with mysql 8 and php and you see the following error: CDbConnection failed to open the DB connection: SQLSTATE[HY000] [2054] The server requested authentication method unknown to the client OR  PHP Fatal error:  Uncaught PDOException: PDO::__construct(): The server requested authentication method unknown to the client [caching_sha2_password]  It maybe due to  PHP devs might have not implemented the MySQL's 8.0 connection protocol ( auth with caching_sha2_password ) within the newer PHP versions. If you want to use mysql >= 8 and you dont care about caching_sha2_password,  If you are running a fresh install of mysql 8, just select the second option as shown in the image. Otherwise, you need to  configure MySQL 8.0 to run in mysql_native_password mode. As it can't configured in my.cnf, change the user profile as:- ALTER USER 'mysqlUsername'@'localhost' IDENTIFIED WITH mysql_native_password BY 'mysqlUs...

 Open the Run command (Win + R), in it type: gpedit.msc and press enter Navigate to: Computer Configuration -> Administrative Templates -> Windows Components -> Windows Update Open it and change the Configure Automatic Updates setting to ‘2 - Notify for download and notify for install’ Open the Settings app (Win + I) and navigate to -> Update and Security -> Windows Updates. Click ‘Check for updates’ which applies the new configuration setting. Restart system

For deleting 'n' number of commands frm bash history, first type history command in shell, #history for example if you need to delete commands from line 520 to line 637 . execute the command as follows. #for h in $(seq 520 637 | tac); do history -d $h; done thats it.

If you are running the hive command as root and still recieve the same error, do the following root@hadoop_server:~# sudo -u hdfs hadoop fs -mkdir /user/root root@hadoop_server:~# sudo -u hdfs hadoop fs -chown root:root /user/root this should fix the problem and you will be able to run the hive command line.

If  trying isql from server gives the following error, IM002][unixODBC][Driver Manager]Data source name not found, and no default driver specified [ISQL]ERROR: Could not SQLConnect Then check the results of following commands in servers odbcinst -q -s odbcinst -q -d if you find any error means that the server is unable to read both odbc.ini and odbcinst.ini files. To resolve this configure the environment variable of server as  export ODBCSYSINI=/etc/ export ODBCINI=/etc/odbc.ini this should fix the error.

You can add an environment variable using the export command. But you can see that once you logout, the parameters you added wont be there. So inorder to add those variables permanently after adding the variable using export command, for example [root@server ~]# export LD_LIBRARY_PATH=/usr/lib/oracle/12.1/client64/lib:/usr/lib:/usr/lib64:  we need to add the same command line in the file /etc/profile or /etc/bashrc  so that it will make the variable permanent for all users. If the change is neeed only for the current user annd the command in the .bashrc file inside the home folder of the current user.

If you find that the server is using excess amount of physical disk space; try a df -h and find out the partition where the disk usage is getting higher. root@server:~# df -h Filesystem      Size  Used Avail Use% Mounted on /dev/vda1       242G  194G   36G  85% / udev             10M     0   10M   0% /dev tmpfs           6.3G   41M  6.3G   1% /run tmpfs            16G     0   16G   0% /dev/shm tmpfs           5.0M     0  5.0M   0% /run/lock tmpfs            16G     ...