关于Doc ID 317441.1提供的查看当前使用临时表空间的SQL存在的问题
关于Doc ID 317441.1提供的查看当前使用临时表空间的SQL存在的问题
How Do You Find Who And What SQL Is Using Temp Segments (Doc ID 317441.1)
对于10.1以上的版本，该文档提供如下SQL查询，稍微改造了下。
SELECT a.username, a.sid, a.serial#, a.osuser, b.tablespace, b.blocks*8/1024 use_temp_mb, c.sql_text FROM v$session a, v$tempseg_usage b, v$sqlarea c WHERE a.saddr = b.session_addr AND c.address= a.sql_address AND c.hash_value = a.sql_hash_value ORDER BY b.tablespace, b.blocks;
但实际上使用如下语句查询后，存在一些其他会话也在使用temp空间。
set line 300 col username for a25 col tablespace for a10 col sql_id for a13 col prev_sql_id for a13 col SEGTYPE for a10 col contents for a10 select s.sid, s.serial#, s.username, s.sql_id, s.prev_sql_id, --u.sql_id, u.tablespace, u.contents, u.segtype, u.extents, u.blocks, round(((u.blocks * P.VALUE) / 1024 / 1024), 2) MB from v$session s, v$sort_usage u, SYS.V_$SYSTEM_PARAMETER P where s.saddr = u.session_addr AND UPPER(P.NAME) = 'DB_BLOCK_SIZE' order by MB DESC;
14:38:42 SYS@test2(2217)> set line 300 14:45:17 SYS@test2(2217)> col username for a25 14:45:17 SYS@test2(2217)> col tablespace for a10 14:45:17 SYS@test2(2217)> col sql_id for a13 14:45:17 SYS@test2(2217)> col prev_sql_id for a13 14:45:17 SYS@test2(2217)> col SEGTYPE for a10 14:45:17 SYS@test2(2217)> col contents for a10 14:45:17 SYS@test2(2217)> select s.sid, 14:45:18 2 s.serial#, 14:45:18 3 s.username, 14:45:18 4 s.sql_id, 14:45:18 5 s.prev_sql_id, 14:45:18 6 --u.sql_id, 14:45:18 7 u.tablespace, 14:45:18 8 u.contents, 14:45:18 9 u.segtype, 14:45:18 10 u.extents, 14:45:18 11 u.blocks, 14:45:18 12 round(((u.blocks * P.VALUE) / 1024 / 1024), 2) MB 14:45:18 13 from v$session s, v$sort_usage u, SYS.V_$SYSTEM_PARAMETER P 14:45:18 14 where s.saddr = u.session_addr 14:45:18 15 AND UPPER(P.NAME) = 'DB_BLOCK_SIZE' 14:45:18 16 order by MB DESC; SID SERIAL# USERNAME SQL_ID PREV_SQL_ID TABLESPACE CONTENTS SEGTYPE EXTENTS BLOCKS MB ---------- ---------- ------------------------- ------------- ------------- ---------- ---------- ---------- ---------- ---------- ---------- 1374 3955 XXXXXXX_XXXX 38mq996b6vyf9 TEMP TEMPORARY LOB_DATA 6777 867456 6777 1308 1925 XXXXXXX_XXXX 4s5t8xn6xtksd 4s5t8xn6xtksd TEMP TEMPORARY LOB_DATA 1272 162816 1272 1374 3955 XXXXXXX_XXXX 38mq996b6vyf9 TEMP TEMPORARY LOB_INDEX 261 33408 261 1308 1925 XXXXXXX_XXXX 4s5t8xn6xtksd 4s5t8xn6xtksd TEMP TEMPORARY LOB_INDEX 92 11776 92 2213 40587 XXXXXXX gcshr3q6xnhu6 TEMP TEMPORARY LOB_DATA 2 256 2 2039 60903 XXXXXXX_XXX 4d3s1h918g6kn TEMP TEMPORARY LOB_DATA 2 256 2 995 2333 XXXXXXX_XXX 4d3s1h918g6kn TEMP TEMPORARY LOB_DATA 2 256 2 998 2205 XXXXXXX_XXXXXXXX f7rwpfmt8qbds TEMP TEMPORARY LOB_DATA 1 128 1 879 42597 XXXXXXX_XX 75p9dz19bafvz TEMP TEMPORARY LOB_DATA 1 128 1 1256 2839 XXXXXXX_XXXX cvy6vzrh3m9ug TEMP TEMPORARY LOB_DATA 1 128 1 843 15 DBSNMP 520mkxqpf15q8 TEMP TEMPORARY LOB_DATA 1 128 1 620 27071 DBSNMP 520mkxqpf15q8 TEMP TEMPORARY LOB_DATA 1 128 1 419 11859 XXXXXXX_XXXX f7rwpfmt8qbds TEMP TEMPORARY LOB_DATA 1 128 1 68 1683 DBSNMP 520mkxqpf15q8 TEMP TEMPORARY LOB_DATA 1 128 1 1403 5365 XXXXXXX 43x5v5s6c4hmv TEMP TEMPORARY LOB_DATA 1 128 1 1458 443 XXXXXXX_XXX 6cs5y9sk09bv7 TEMP TEMPORARY LOB_DATA 1 128 1 1521 25765 QA_XXXXXXX_XXX 17wjjj5cghz9r TEMP TEMPORARY LOB_DATA 1 128 1 1625 3 DBSNMP g1n7yg84rqj0y TEMP TEMPORARY LOB_DATA 1 128 1 1952 1091 XXXXXXX_XXXX 1jhknmxn3zwn7 TEMP TEMPORARY LOB_DATA 1 128 1 2234 1095 XXXXXXX_XXXX f7rwpfmt8qbds TEMP TEMPORARY LOB_DATA 1 128 1 2039 60903 XXXXXXX_XXX 4d3s1h918g6kn TEMP TEMPORARY LOB_INDEX 1 128 1 995 2333 XXXXXXX_XXX 4d3s1h918g6kn TEMP TEMPORARY LOB_INDEX 1 128 1 2089 47 SYSTEM 53zazd5rv1ca9 TEMP TEMPORARY LOB_DATA 1 128 1 1018 17 DBSNMP 520mkxqpf15q8 TEMP TEMPORARY LOB_DATA 1 128 1 24 rows selected. Elapsed: 00:00:00.06
可以发现，比如sid=1374的那一行中，prev_sql_id为38mq996b6vyf9，这条sql经过确认并不会消耗sql语句。
这是因为会话1374曾经执行过消耗了大量临时表空间的SQL，然后后续有执行了其他SQL，因此Doc ID 317441.1提供的SQL就没捕捉到1374会话。
因此，想要找出实际的情况，不推荐使用Doc ID 317441.1提供的SQL，用我上边另外的SQL查询即可。
至于如何找出会话1374实际消耗temp空间的SQL，用v$open_cursor慢慢找吧。。
另外，其他通过dba_hist_sess_history追溯历史时刻temp表空间占用问题的，
这两例，和上边一样均无法找出“隐藏于幕后”的占用临时表空间的语句的会话，
只能找出那个时候正在使用临时表空间的SQL的会话。
这里提供一下该脚本：
select instance_number,to_char(a.sample_time,'yyyy-mm-dd hh24:mi:ss') sample_time,sum(temp_space_allocated)/1024/1024 mb,sql_id from dba_hist_active_sess_history a where a.temp_space_allocated is not null and a.sample_time between to_date('2020-10-27 12:49:00','yyyy-mm-dd hh24:mi:ss') and to_date('2020-10-27 12:51:00','yyyy-mm-dd hh24:mi:ss') group by instance_number,to_char(a.sample_time,'yyyy-mm-dd hh24:mi:ss'),sql_id order by 1,2; 13:55:30 SYS@test1(1222)> select instance_number,to_char(a.sample_time,'yyyy-mm-dd hh24:mi:ss') sample_time,sum(temp_space_allocated)/1024/1024 mb,sql_id 13:57:01 2 from dba_hist_active_sess_history a 13:57:01 3 where a.temp_space_allocated is not null and a.sample_time between to_date('2020-10-27 12:49:00','yyyy-mm-dd hh24:mi:ss') and to_date('2020-10-27 12:51:00','yyyy-mm-dd hh24:mi:ss') 13:57:01 4 group by instance_number,to_char(a.sample_time,'yyyy-mm-dd hh24:mi:ss'),sql_id 13:57:01 5 order by 1,2; INSTANCE_NUMBER SAMPLE_TIME MB SQL_ID --------------- -------------------------------------------------- ---------- ------------------------- 1 2020-10-27 12:50:24 1 4b4pkcjgtxbqq 1 2020-10-27 12:50:34 1815 4b4pkcjgtxbqq 1 2020-10-27 12:50:44 3583 4b4pkcjgtxbqq 2 2020-10-27 12:50:01 1 f27uxgwvkdcgv Elapsed: 00:01:20.12
监控：
如何随着时间的推移监控临时段的使用情况？（文档 ID 364417.1）
其他
How Can Temporary Segment Usage Be Monitored Over Time? (文档 ID 364417.1)
