[sqlite] Exception Problem - Heap

[Pramoda M. A]

Hi All,

 

I am getting an exception/error after some data is retrieved.  I have
copied here the screenshot...

After storing 250 rows of data, it is giving exception...

How to use malloc functions efficiently?

 

Please help me anybody...

 

 

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Re: [sqlite] Full Table Read

[Alexey Pechnikov]

Hello!

В сообщении от Saturday 14 February 2009 00:33:38 Nathan Biggs написал(а):
> Is there a faster way to read an entire table other then:
>
> select * from table
>
> Not that is is slow, just curious.

On linux you can do 
dd if=database.db of=/dev/null bs=1M
and after perform "select ..."

This trick does put your db to OS file cache and all read operations will be 
extremely fast.

Best regards, Alexey.
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Re: [sqlite] sqlite3 cmd line: arrow

[David Easley]

> Install libreadline5-dev before running configure.  The readline
> library is what provides the command line editing and recall.

Thank you Roger - that fixed it.

I've raised a minor ticket on the INSTALL document, suggesting it should
mention this.

David
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Re: [sqlite] having the Top N for each group

[Edzard Pasma]

Hello, 

May be this is some idea:
GROUP_CONCAT is a built-in aggregate function, that efficiently returns a list 
(as text) of items in each group. If you add ORDER By (before the group by) it 
also arranges the ordering. But it does not let you restrict the number of 
elements in each group, to only the top-N. I thought may be SUBSTR is a further 
solution. The use of LIMIT would be more elegant but I don't see how.

is a TopN function planned for the future version of sqlite?
?

Edzard Pasma

--- sylvain.point...@gmail.com wrote:

From: Sylvain Pointeau 
To: sqlite-users@sqlite.org
Subject: [sqlite] having the Top N for each group
Date: Sat, 14 Feb 2009 09:21:15 +0100

Hello all,
I am wondering if we have a method faster then the INNER JOIN which
can be very slow in case of large number of rows, which is my case.
I was thinking of a UDF that increment a number if the concatenation of the
key column (or group columns) is the same, means:
select col1, col2, udf_topN(col1||col2) from TTT order by value group by
col1,col2

will result into

1,1,1
1,1,2
1,1,3
2,1,1
2,1,2
2,1,3
4,3,1
4,3,2
etc


however I don't really find how to keep, initialize, and destroy a variable
in a UDF for a query time execution

do you have some idea?
is a TopN function planned for the future version of sqlite?

Many thanks,
Sylvain
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[sqlite] having the Top N for each group

[Sylvain Pointeau]

Hello all,
I am wondering if we have a method faster then the INNER JOIN which
can be very slow in case of large number of rows, which is my case.
I was thinking of a UDF that increment a number if the concatenation of the
key column (or group columns) is the same, means:
select col1, col2, udf_topN(col1||col2) from TTT order by value group by
col1,col2

will result into

1,1,1
1,1,2
1,1,3
2,1,1
2,1,2
2,1,3
4,3,1
4,3,2
etc


however I don't really find how to keep, initialize, and destroy a variable
in a UDF for a query time execution

do you have some idea?
is a TopN function planned for the future version of sqlite?

Many thanks,
Sylvain
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