I want to empty a table in hbase… eg: user
. Is there any command or function to empty the table without deleting it…
My table structure is :
$mutations = array( new Mutation( array( 'column' => 'username:1', 'value' =>$name ) ), new Mutation( array( 'column' => 'email:1', 'value' =>$email ) ) ); $hbase->mutateRow("user",$key,$mutations);
Can someone help me?
Advertisement
Answer
There’s no single command to clear Hbase table, but you can use 2 workarounds: disable, delete, create table, or scan all records and delete each.
Actually, disable, delete and create table again takes about 4 seconds.
// get Hbase client $client = <Your code here>; $t = "table_name"; $tables = $client->getTableNames(); if (in_array($t, $tables)) { if ($client->isTableEnabled($t)) $client->disableTable($t); $client->deleteTable($t); } $descriptors = array( new ColumnDescriptor(array("name" => "c1", "maxVersions" => 1)), new ColumnDescriptor(array("name" => "c2", "maxVersions" => 1)) ); $client->createTable($t, $descriptors);
If there’s not a lot of data in table – scan all rows and delete each is much faster.
$client = <Your code here>; $t = "table_name"; // i don't remember, if list of column families is actually needed here $columns = array("c1", "c2"); $scanner = $client->scannerOpen($t, "", $columns); while ($result = $client->scannerGet($scanner)) { $client->deleteAllRow($t, $result[0]->row); }
In this case data is not deleted physically, actually it’s “marked as deleted” and stays in table until next major compact.