Examples with RestorableMeter org.apache.cassandra.metrics.RestorableMeter used on opensource projects

Example 6 with RestorableMeter

use of org.apache.cassandra.metrics.RestorableMeter in project cassandra by apache.

the class SystemKeyspace method getSSTableReadMeter.

/**
     * Returns a RestorableMeter tracking the average read rate of a particular SSTable, restoring the last-seen rate
     * from values in system.sstable_activity if present.
     * @param keyspace the keyspace the sstable belongs to
     * @param table the table the sstable belongs to
     * @param generation the generation number for the sstable
     */
public static RestorableMeter getSSTableReadMeter(String keyspace, String table, int generation) {
    String cql = "SELECT * FROM system.%s WHERE keyspace_name=? and columnfamily_name=? and generation=?";
    UntypedResultSet results = executeInternal(format(cql, SSTABLE_ACTIVITY), keyspace, table, generation);
    if (results.isEmpty())
        return new RestorableMeter();
    UntypedResultSet.Row row = results.one();
    double m15rate = row.getDouble("rate_15m");
    double m120rate = row.getDouble("rate_120m");
    return new RestorableMeter(m15rate, m120rate);
}