Disabling a Table using HBase Shell
To delete a table or change its settings, you need to first disable the table using the disable command. You can re-enable it using the enable command.
Syntax
Given below is an example that shows how to disable a table.
After disabling the table, you can still sense its existence through list and exists commands. You cannot scan it. It will give you the following error.
This command is used to find whether a table is disabled. Its syntax is as follows.
This command is used to disable all the tables matching the given regex. The syntax for disable_all command is given below.
To verify whether a table is disabled, isTableDisabled() method is used and to disable a table, disableTable() method is used. These methods belong to the HBaseAdmin class.
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To delete a table or change its settings, you need to first disable the table using the disable command. You can re-enable it using the enable command.
Syntax
disable ‘emp’Example
Given below is an example that shows how to disable a table.
hbase> disable 'emp' 0 row(s) in 1.2760 secondsVerification
After disabling the table, you can still sense its existence through list and exists commands. You cannot scan it. It will give you the following error.
hbase> scan 'emp' ROW COLUMN + CELL ERROR: emp is disabled.is_disabled
This command is used to find whether a table is disabled. Its syntax is as follows.
hbase> is_disabled 'table name'The following example verifies whether the table named emp is disabled. If it is disabled, it will return true and if not, it will return false.
hbase> is_disabled 'emp' true 0 row(s) in 0.0348 secondsdisable_all
This command is used to disable all the tables matching the given regex. The syntax for disable_all command is given below.
hbase> disable_all 'a.*'Suppose there are 5 tables in HBase, namely ashok, ajay, anjali, akila, and anand. The following code will disable all the tables starting with a.
hbase> disable_all 'a.*' ashok ajay anjali akila anand Disable the above 5 tables (y/n)? y 5 tables successfully disabledDisable a Table Using Java API
To verify whether a table is disabled, isTableDisabled() method is used and to disable a table, disableTable() method is used. These methods belong to the HBaseAdmin class.
package com.ashok.hbase; import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.MasterNotRunningException; import org.apache.hadoop.hbase.client.HBaseAdmin; public class DisableTable{ public static void main(String args[]) throws MasterNotRunningException, IOException{ // Instantiating configuration class Configuration conf = HBaseConfiguration.create(); // Instantiating HBaseAdmin class HBaseAdmin admin = new HBaseAdmin(conf); // Verifying weather the table is disabled Boolean bool = admin.isTableDisabled("emp"); System.out.println(bool); // Disabling the table using HBaseAdmin object if(!bool){ admin.disableTable("emp"); System.out.println("Successfully Table disabled"); } } }
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