HW enqueue The HW enqueue is used to serialize the allocation of space beyond the high water mark of a segment. If this is a point of contention for an object, then manual allocation of extents solves the problem. SQL> select p1, p2, p3 from v$session_wait where event = 'enq: HW - contention'; P1 P2 P3 ---------- ---------- ---------- 1213661190 7 140003563 1213661190 7 140003563 1213661190 7 140003563 1213661190 7 140003563 1213661190 7 140003563 1213661190 7 140003563 1213661190 7 140003563 7 rows selected SQL> SQL> select dbms_utility.data_block_address_block(140003563), 2 dbms_utility.data_block_address_file(140003563) 3 from dual 4 ; DBMS_UTILITY.DATA_BLOCK_ADDRES DBMS_UTILITY.DATA_BLOCK_ADDRES ------------------------------ ------------------------------ 1591531 33 SQL> select name from v$tablespace where ts#=7; NAME ------------------------------ INFORES 通过下面语句找到热点segment select * from dba_extents.segment_name where tablespace_name = 'INFORES' and FILE_ID = 33 and 1591531 between block_id and block_id + blocks
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