9. Bitmap related operations
This type of operation performs bit operations based on bitmap data (for example: bitmap data of bitmap index), or converts other structural data into bitmap data to utilize bit operations. Depending on the specific SQL statement and other related factors, the following operations may appear in the execution plan of the relevant SQL statement.
1）BITMAP AND
Performs an AND operation on two bitmap indexes and fetches data rows from related tables based on the result of the operation. Each bit of the bitmap in the bitmap index represents whether the value of the index field in the corresponding table data row is the corresponding key value of the index. To match and filter the data through the relevant conditions between the key columns of the bitmap index on the table, it only needs to perform the "AND" operation on the bits of the bitmap in the relevant bitmap index. This operation is specifically shown in node 2 in Figure 10-1.
Figure 10-1 Example of bitmap-related operations BITMAP AND