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Oracle

Wait Events - index block split

index block split

While trying to find an index key in an index block, Oracle noticed that the index block was being split. Oracle will wait for the split to finish and try to find the key again. Wait Time:

The session will yield the CPU, so there is no actual waiting time.

Parameter Description
rootdba This is the block that Oracle is trying to split. With the following SQL statement one can find the name of the index that this block belongs to:
select name, kind
  from ext_to_obj_view
 where file#  = data_block_address_file(rootdba)
   and lowb  <= data_block_address_block(rootdba)
   and highb >= data_block_address_block(rootdba);
level This is the level of the block that Oracle is trying to split in the index. The leaf blocks are level 0. If the level is > 0, it is a branch block. (The root block can be considered a special branch block).
childdba This is the new block that will contain half of the previous block(rootdba). One can also check to see if this childdba is part of the object:
select name, kind
  from ext_to_obj_view
 where file#  = data_block_address_file(childdba)
   and lowb  <= data_block_address_block(childdba)
   and highb >= data_block_address_block(childdba);
Note: The amount of time waited for this event is not as important as the number of times that one has to wait. Always check the name of the index and check in the application to see what kind of operations are happening.