有人可以告诉我为什么下面的查询被解雇以及什么时候被解雇.我相信这个问题会对性能产生巨大影响.我无法追踪这被解雇的地方.
查询:
SELECT SUM (used), SUM (total)
FROM (SELECT /*+ ORDERED */
SUM (d.BYTES) / (1024 * 1024) - MAX (s.BYTES) used,
SUM (d.BYTES) / (1024 * 1024) total
FROM ( SELECT tablespace_name, SUM (BYTES) / (1024 * 1024) BYTES
FROM ( SELECT/*+ ORDERED USE_NL(obj tab) */DISTINCT ts.NAME
FROM SYS.obj$ obj, SYS.tab$ tab, SYS.ts$ ts
WHERE obj.owner# = USERENV ('SCHEMAID')
AND obj.obj# = tab.obj#
AND tab.ts# = ts.ts#
AND BITAND (tab.property, 1) = 0
AND BITAND (tab.property, 4194400) = 0) tn,
dba_free_space sp
WHERE sp.tablespace_name = tn.NAME
GROUP BY sp.tablespace_name) s, dba_data_files d
WHERE d.tablespace_name = s.tablespace_name
GROUP BY d.tablespace_name)
Run Code Online (Sandbox Code Playgroud)
它在SYS.TS $和SYS.FILE $上进行全表扫描.我相信它正在利用数据库的最大资源.
请帮我.
提前致谢.
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