Re: Is there any method to keep table in memory at startup - Mailing list pgsql-hackers

From Andrew Hammond
Subject Re: Is there any method to keep table in memory at startup
Date
Msg-id 408FB168.7020500@ca.afilias.info
Whole thread Raw
In response to Re: Is there any method to keep table in memory at startup  (Vinay Jain <vinayj@sarathi.ncst.ernet.in>)
Responses Re: Is there any method to keep table in memory at startup  (Vinay Jain <vinayj@sarathi.ncst.ernet.in>)
List pgsql-hackers
Vinay Jain wrote:
> Hi
>    thank you for such a useful information...
>    but actually in my case if i keep table in disk it  significantly 
> degrades performance and even for a table of  10 rows it takes 1-2 
> minutes I think u r not beliving it ! am i right
> for example
> I create a table in which i use my customized data type say student
> create table student
> (Name INDCHAR //INDCHAR is customized data type
>    age integer);
> now i give query like this
> select * from student order by name;
> it will search for it's comparator operator (<) and related function...
> in that function there is one lookup table if that table is in memory no 
> problem! (oh but it can't be) if it is in disk  my program makes 
> connection to database and execute query which is  just a select 
> statement on a simple where condition of equality. then closes connection

There's your problem. Creating database connections is an expensive 
operation. They are not intended to be opened and closed often or 
quickly. Open your database connection at the beginning of your program, 
and close it at the end.

You could also throw an index on the column you're using in your order 
by clause, but that won't make a difference until your table get a 
little bigger.

Please take further questions of this nature to the pgsql-novice list.

> so every time less than operator(<) is called it does the same task..
> what i feel in table of 10 rows how many times the < operator will be 
> called(NO idea but must be > 10 times)
> is there any solution..
> thanks in advance
> regards
> vinay



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