Re: SQL Diff ?

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On 08/25/07 22:21, Kevin Kempter wrote:
> On Saturday 25 August 2007 21:10:19 Ron Johnson wrote:
>> On 08/25/07 21:51, Kevin Kempter wrote:
>>> Hi List;
>>>
>>> I have a very large table (52million rows) - I'm creating a copy of it to
>>> rid it of 35G worth of dead space, then I'll do a sync, drop the original
>>> table and rename table2.
>> What is your definition of "dead space"?
>>
>> Bad rows, duplicate rows, old rows? Something else?
>
> deleted rows that should have been cleaned up with vacuum, problem is the
> client let it go so long that now I cant get a vacuum to finish cause it
> impacts the day2day operations too much. Long story, see my recent questions
> on the performance list for more info.

OK.

>
>>> Once I have the table2 as a copy of table1 what's the best way to select
>>> all rows that have been changed, modified in table1 since the initial
>>> laod from table1 into table2?

Is this a 24x7 database?

>>> Also I'll need to delete any rows in table2 that no longer remain in
>>> table1.
>>>
>>> There is no change date column
>>> I could do something like select * from table1 where col1 || col2 || col3
>>> etc not in (select col1 || col2 || col3 etc from table2)
>>>
>>> but this would be ineffecient & slow.
>>>
>>> Anyone have a suggestion to do this in an efficient manner?
>>>
>>> Thanks in advance

- --
Ron Johnson, Jr.
Jefferson LA USA

Give a man a fish, and he eats for a day.
Hit him with a fish, and he goes away for good!

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