In this chapter I discuss how a row in a Apache HBase table is found. The sequence used to find a row/s is as follows:
HBase identifies the file/s (HFiles) that store/s the row/s requested using the metadata
Each HFile keeps a block index that identifies the block in the HFile where a row is found
After finding the block that could contain a row, HBase scans the block to retrieve all key/value pairs requested, and copy of the key/value pairs is stored in the block cache in memory
The requested row is returned to the client
Subsequent requests for the same row/s get served from ...