Database Reference
In-Depth Information
Figure 10-9.
An execution plan decomposed in blocks. The numbers on the left identify the operations.
The letters on the right identify the blocks
Figure 10-10.
Parent-child relationships of the execution plan shown in Figure
10-9
Initially, it's necessary to both decompose the execution plan into basic blocks and recognize the order of
execution. To do so, you carry out the following steps. To read an execution plan at first, you have to identify the
combine operations (both related and unrelated) it's composed of. In other words, you identify each operation having
more than one child. In the example in Figure
10-9
, the combine operations are the following: 3, 4, 5, 6, and 14. Then,
