DB2 SELECT COUNT（*）问题 [英] DB2 SELECT COUNT(*) problem
问题描述
有没有人在大桌子上遇到这个问题。返回结果似乎需要很长时间（半小时:-(）。
SELECT COUNT（*）来自COORDINATE
A奇怪的是，在查询过程中，临时空间（系统管理）不断增长：
14346747904 12月2日16:22 SQL00002.TDA
它几乎和当前的桌子一样大（17GB）。有什么意见吗？
非常感谢，
Bing
Hi,
Has anyone got problem with this on large table. It seems it take ages to return the result ( half an hour :-( ).
SELECT COUNT(*) FROM COORDINATE
A strange thing is the tempory space (System Managed) keeps growing during the query:
14346747904 Dec 2 16:22 SQL00002.TDA
It''s almost as large as the current table (17GB). Any comments?
Many thanks,
Bing
推荐答案
Bing Wu写道：
Bing Wu wrote:
你好，
有没有人有问题这个在大桌子上。似乎需要很长时间才能返回结果（半小时:-(）。
SELECT COUNT（*）来自COORDINATE
一件奇怪的事情在查询期间，临时空间（系统管理）不断增长：
14346747904 12月2日16:22 SQL00002.TDA
它几乎与当前表一样大（17GB）。有什么意见吗？
非常感谢，
Bing
Hi,
Has anyone got problem with this on large table. It seems it take ages to return the result ( half an hour :-( ).
SELECT COUNT(*) FROM COORDINATE
A strange thing is the tempory space (System Managed) keeps growing during the query:
14346747904 Dec 2 16:22 SQL00002.TDA
It''s almost as large as the current table (17GB). Any comments?
Many thanks,
Bing
尝试：
从...中选择计数（1）
并查看。
hth。
Wolfgang
try:
select count(1) from ...
and see.
hth.
Wolfgang
非常感谢提示。好像还需要很长时间。
Bing
Wolfgang Riedel写道：
Many thanks for the hint. It seems still taking long time.
Bing
Wolfgang Riedel wrote:
试试：
从...中选择计数（1）。
hth。
Wolfgang
try:
select count(1) from ...
and see.
hth.
Wolfgang
>有没有人在大表上遇到此问题。似乎需要很长时间才能
>Has anyone got problem with this on large table. It seems it take ages to
返回结果（半小时:-(）。
SELECT COUNT（*）FROM COORDINATE
return the result ( half an hour :-( ).
SELECT COUNT(*) FROM COORDINATE
你有解释吗？也许一个指数会有帮助
have you ran explain ? maybe an index would help
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