Method and device for searching indexes for sensor tag data

A device for searching indexes for sensor tag data, the device comprising:

• a memory having sensor tag data stored as a time series;
• an interface configured to receive tag names and time segment information for searching sensor tag data;
• and
• a processor configured to determine partitions of the memory having the sensor tag data stored therein based on the time segment information, the processor configured to determine corresponding indexes and leaf nodes for the determined partitions based on the tag names and the time segment information,
• wherein data stored in the memory is stored as records consisting of <time, tag name, value>, the records are stored for each partition until a number of the stored records reaches a maximum count,
• an index is generated for the partition for which storage is completed with a key in a form of <tag name, time>, and fields <value, RID> are recorded in a data region of the index,
• wherein the processor performs a fault recovery algorithm to restart the device in an event of an abnormal termination caused by an abnormal operation of a hardware and software of the device,
• and the processor does not perform a fault recovery operation for sensor data for which a merging of the index files is complete such that data is no longer newly recorded and there are no data updates, and
• wherein the processor determines whether or not an error due to an abnormal operation during a merging of the index files occurred based on a completed status of a head region and a tail region of the index file,
• and if the error occurred, the processor deletes the index file and performs a record search by using first index files of a level before the merging.