(Digest from it_pub) Rebuild, you will also use the temporary table space ask Tom on the rebuild index on the rebuild index: if you need to rebuild your indexes, you need 2x the space - You'll Have the old and the new index for a period of time. if you do it online, you'll NEED Additional Space to Hold The Changes That Are Made During The Rebuild As Well2 × Space is currently used in the tableSpace in the table, someone has asked similar questions Rebuild INDEX Why do we know that the index is an ordered storage. However, in the block inside the block, the storage of index key values is disorderly, you have deposited 1,3, even if it adds a 2 that in the same data. Inside the block, the database does not move the storage of 1, 3 when reading, Oracle can be sorted in a simple block, and oracle obviously does not follow 1, 2 when the index is reconstructed. 3 ......... The index order to read the index content because its cost of oracle actually implemented the Fast Full Scan read the data read in the order of Block, which needs to be re-sort, and then reconstruct Index This reconstructed index is more ordered in physical storage. This can be observed by block dump. It is actually sorted, large sort (as long as Sort Area is not covered), I have to use temporary table space. I have made two Test. My INDEX size is about 7m. First, I only open the tableSpace in Index to 10m, the temporary table space is large, and the Rebuild Times cannot extend the TEMP segment on the tableSpace in Index. Increase the table space, Rebuild successfully. (At least to 20M) Only open the temporary table space only to 5m, the table space is driven to 20m, and Rebuild will not expand on the TEMP table space (this is because of the need to be sorted, but Sort Area can't be used, so it is temporary Table space), increasing the temporary table space to 10m, Rebuild success. 1. The storage of indexes is that the block is inside, and the block is ordered. 2. Read Fast Full Scan3 when it is in the block. It is not the cost of reading indexes. It is said that the order is unordered. The cost of the index is high, so it will be read using a Fast Full Scan mode.
