Horizontal splitting

Use horizontal splitting if:

Generally, horizontal splitting requires different table names in queries, depending on values in the tables. In most database applications this complexity usually far outweighs the advantages of table splitting .

As long as the index keys are short and indexes are used for queries on the table, doubling or tripling the number of rows in the table may increase the number of disk reads required for a query by only one index level. If many queries perform table scans, horizontal splitting may improve performance enough to be worth the extra maintenance effort.

Figure 6-9 shows how you might split the authors table to separate active and inactive authors:

Figure 6-9: Horizontal partitioning of active and inactive data