关于DROP表时表空间的释放问题。

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查看11 | 回复9 | 2014-3-10 14:09:19 | 显示全部楼层 |阅读模式
不大明白表空间的释放机制是怎么样。我这边出现的问题是在表空间接近爆的时候。DROP了很多TABLE.
但是表空间一直不会释放。有时候二三小时才释放。有时候得七八个小时。
搞得我每次清表的时候得对表先进行清空操作后再DROP!
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
i don't understand what you mean, can you capture screenshot as what i did below to show what you were talking?
(taoewang@p6db2serv) / $ db2 "create tablespace tbs1 managed by database using (file '/home2/taoewang/data0' 10M)"
list tablespace has:
Tablespace ID
= 7
Name
= TBS1
Type
= Database managed space
Contents
= All permanent data. Large table space.
State
= 0x0000
Detailed explanation:
Normal
Total pages
= 2560
Useable pages
= 2528
Used pages
= 96
Free pages
= 2432
High water mark (pages)
= 96
Page size (bytes)
= 4096
Extent size (pages)
= 32
Prefetch size (pages)
= 32
Number of containers
= 1

(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "create table tb1 (c1 char(100), c2 char(100)) in tbs1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tbs1 values ('1','2')"
DB21034EThe command was processed as an SQL statement because it was not a
valid Command Line Processor command.During SQL processing it returned:
SQL0204N"TAOEWANG.TBS1" is an undefined name.SQLSTATE=42704
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 values ('1','2')"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 "insert into tb1 select * from tb1"
DB20000IThe SQL command completed successfully.
(taoewang@p6db2serv) /:/proj/p0/dbt/service/pmrs/53672.7TD.000 $ db2 list tablespaces
Tablespace ID
= 7
Name
= TBS1
Type
= Database managed space
Contents
= All permanent data. Large table space.
State
= 0x0000
Detailed explanation:
Normal
Total pages
= 2560
Useable pages
= 2528
Used pages
= 256
Free pages
= 2272
High water mark (pages)
= 256
Page size (bytes)
= 4096
Extent size (pages)
= 32
Prefetch size (pages)
= 32
Number of containers
= 1
(taoewang@p6db2serv) / $ db2 "drop table tb1"
DB20000IThe SQL command completed successfully.
then list tablespace:
Tablespace ID
= 7
Name
= TBS1
Type
= Database managed space
Contents
= All permanent data. Large table space.
State
= 0x0000
Detailed explanation:
Normal
Total pages
= 2560
Useable pages
= 2528
Used pages
= 96
Free pages
= 2432
High water mark (pages)
= 96
Page size (bytes)
= 4096
Extent size (pages)
= 32
Prefetch size (pages)
= 32
Number of containers
= 1
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
做这样测试的时候确实没有这个问题。我也测过。
如果数据量大的话这个问题就出现了。我的表空间达到了一个T。DROP掉的很多是千万行上亿的数据的表。
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
问题发生时抓一下screenshot,光这样说没有办法解决问题的,一切要从真实数据出发
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
下次捉个给你看看。
CALL 800 .回复我表在DROP的过程中空间是会慢慢释放的。具体释放时间需要看系统的繁忙情况。
我DROP完表的时候,去查SNAPSHOT表空间快照的VIEW的时候确实空间是显示下降了。
但是用LIST TABLESPACES 的时候空间就还没有释放。
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
抓快照的是准的。
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
drop 表不及时释放空间? 我没有遇到过!
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
原帖由 yyran 于 2008-1-17 22:46 发表
下次捉个给你看看。
CALL 800 .回复我表在DROP的过程中空间是会慢慢释放的。具体释放时间需要看系统的繁忙情况。
我DROP完表的时候,去查SNAPSHOT表空间快照的VIEW的时候确实空间是显示下降了。
但是用LIST TABLESPACES 的时候空间就还没有释放。

这个如何解释呢?
难道是修改表空间的object map时间慢?
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
原帖由 yyran 于 2008-1-17 22:27 发表
做这样测试的时候确实没有这个问题。我也测过。
如果数据量大的话这个问题就出现了。我的表空间达到了一个T。DROP掉的很多是千万行上亿的数据的表。

这么大,用的什么版本?pagesize设的是多少?好像最大是512G阿?
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千问 | 2014-3-10 14:09:19 | 显示全部楼层
LZ的问题,我确实也是遇到过的。 抓快照来看吧还是。
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