The Ultimate Guide to High Availability with MariaDB

HBase storage engine

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Data mapping from HBase to SQL

Hbase data model and operations

1.1 HBase data model

  • An HBase table consists of rows, which are identified by row key.
  • Each row has an arbitrary (potentially, very large) number of columns.
  • Columns are split into column groups, column groups define how the columns are stored (not reading some column groups is an optimization).
  • Each (row, column) combination can have multiple versions of the data, identified by timestamp.

1.2 Hbase read operations

HBase API defines two ways to read data:

  • Point lookup: get record for a given row_key.
  • Point scan: read all records in [startRow, stopRow) range.

Both kinds of scans allow to specify:

  • A column family we're interested in
  • A particular column we're interested in

The default behavior for versioned columns is to return only the most recent version. HBase API also allows to ask for

  • versions of columns that were valid at some specific timestamp value;
  • all versions that were valid within a specifed [minStamp, maxStamp) interval.
  • N most recent versions We'll refer to the above as [VersionedDataConds].

One can see two ways to map HBase tables to SQL tables:

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