Script:partition table into rowid extent chunks
以下脚本可以用于将表按照rowid范围分区,获得指定数目的rowid Extent区间(Group sets of rows in the table into smaller chunks), 以便于非分区表利用rowid来实现并行删除或更新:
REM rowid_ranges should be at least 21 REM utilize this script help delete large table REM if update large table Why not online redefinition or CTAS -- This script spits desired number of rowid ranges to be used for any parallel operations. -- Best to use it for copying a huge table with out of row lob columns in it or CTAS/copy the data over db links. -- This can also be used to simulate parallel insert/update/delete operations. -- Maximum number of rowid ranges you can get here is 255. -- Doesn't work for partitioned tables, but with minor changes it can be adopted easily. -- Doesn't display any output if the total table blocks are less than rowid ranges times 128. -- It can split a table into more ranges than the number of extents From Saibabu Devabhaktuni http://sai-oracle.blogspot.com/2006/03/how-to-split-table-into-rowid-ranges.html set verify off undefine rowid_ranges undefine segment_name undefine owner set head off set pages 0 set trimspool on select 'where rowid between ''' ||sys.dbms_rowid.rowid_create(1, d.oid, c.fid1, c.bid1, 0) ||''' and ''' ||sys.dbms_rowid.rowid_create(1, d.oid, c.fid2, c.bid2, 9999) || '''' ||';' from (select distinct b.rn, first_value(a.fid) over(partition by b.rn order by a.fid, a.bid rows between unbounded preceding and unbounded following) fid1, last_value(a.fid) over(partition by b.rn order by a.fid, a.bid rows between unbounded preceding and unbounded following) fid2, first_value(decode(sign(range2 - range1), 1, a.bid + ((b.rn - a.range1) * a.chunks1), a.bid)) over(partition by b.rn order by a.fid, a.bid rows between unbounded preceding and unbounded following) bid1, last_value(decode(sign(range2 - range1), 1, a.bid + ((b.rn - a.range1 + 1) * a.chunks1) - 1, (a.bid + a.blocks - 1))) over(partition by b.rn order by a.fid, a.bid rows between unbounded preceding and unbounded following) bid2 from (select fid, bid, blocks, chunks1, trunc((sum2 - blocks + 1 - 0.1) / chunks1) range1, trunc((sum2 - 0.1) / chunks1) range2 from (select /*+ rule */ relative_fno fid, block_id bid, blocks, sum(blocks) over() sum1, trunc((sum(blocks) over()) / &&rowid_ranges) chunks1, sum(blocks) over(order by relative_fno, block_id) sum2 from dba_extents where segment_name = upper('&&segment_name') and owner = upper('&&owner')) where sum1 > &&rowid_ranges) a, (select rownum - 1 rn from dual connect by level <= &&rowid_ranges) b where b.rn between a.range1 and a.range2) c, (select max(data_object_id) oid from dba_objects where object_name = upper('&&segment_name') and owner = upper('&&owner') and data_object_id is not null) d /
posted on 2010-12-20 20:55 Oracle和MySQL 阅读(249) 评论(0) 编辑 收藏 举报