| 摘要 |
Methods, systems, and computer programs for executing a query having a first and second query value; in a database having at least two composite indexes, where the first index covers a first and second column and the second index covers the second column and a third column. Methods can include executing a query over the first and third columns, by using the first query values to probe the first index to obtain all related second column values, and using the obtained column values to probe the second index for all third column values which satisfy the second query value. A temporary composite index over the first and third columns for the query values can be created. A temporary composite index can be created for a query which was unexpected. |
