Sorry, but I don't see any unanswered questions in your post.

What it will do?
Your answer: print Dumper($ref)
Assuming that you wrote at lease two test records to your table, Dumper will show you a more exact answer than anybody could write here.

will it cause any memory related problem if it has large number of data
Oh, sorry, this sounds like a question, but the answer is (a little bit hidden) also in your post:
selectall_arrayref
This fetches all data and puts it into arrays. Typical arrays are stored in RAM by Perl, so the answer is yes - if your data including Perl's array overhead is larger than your RAM, you'll be in trouble.

Look at the DBI manpage, POD or CPAN page, there is a pretty good example for fetching a huge amount of data while with little memory using prepare/execute/fetch*. Whenever you're thinking about will it cause any memory related problem if it has large number of data, this way will be your friend.
If you really really really need the data as ONE per structure (String, Array, Hash), consider tie'ing it to a temporary file. This will make things slower but the limit will be your free disk space and not your free memory.

In reply to Re: DBI Process. by Sewi
in thread DBI Process. by santhosh_89

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