The row store, meanwhile, continues to read from and write to memory, flash, and disk, and syncs information with the column store. The column store exists only in memory.

Column stores are great (better than a row store) if you're just reading tons of data, but they're much more costly than a row store if you're writing tons of data.

Column stores are preferred for large-scale analytics work because of the way they store data. Instead of storing detailed data in rows, as a traditional relational database does, or in JSON documents ...