topic Re: Do I need to sort a hashed table before reading ? in Application Development and Automation Discussions

Do I need to sort a hashed table before reading ?

Former Member — Fri, 02 Jun 2006 14:14:14 GMT

1) I populate a hashed internal table :

data :

i_droplist type hashed table of t_droplist

with unique key gpart vkont,

select gpart

vkont

into table i_droplist

from zxis_0x_dun_drop

for all entries in i_jointab1

where gpart = i_jointab1-gpart

and vkont = i_jointab1-vkont.

2) read table i_droplist transporting no fields

with table key gpart = p_gpart

vkont = p_vkont.

Before reading the table is it needed to sort the hashed table on the key ?

I think it is not necessary but I am not sure ...

Thanks for your help,

Marie

Re: Do I need to sort a hashed table before reading ?

Former Member — Fri, 02 Jun 2006 14:16:53 GMT

Hi Marie,

It is not Mandatory to use Sort before Read for a hashed table.

Regards,

Santosh

Reward if it helps...

Re: Do I need to sort a hashed table before reading ?

Former Member — Fri, 02 Jun 2006 14:17:23 GMT

No! You can't do it because the system sorts the records while loading them.

Max

Re: Do I need to sort a hashed table before reading ?

Former Member — Fri, 02 Jun 2006 14:19:15 GMT

Hi,

no need.

When you write to the hashed table it uses a hashing algorithm to identify where the record is stored (think if this as writing the location of a page in an index of a book). When you READ this table the system looks up this "index" and retrieves the record. Because of this the retrieval time is constant.

rgds,

latheesh

Message was edited by: Latheesh Kaduthara

Re: Do I need to sort a hashed table before reading ?

Former Member — Fri, 02 Jun 2006 14:19:25 GMT

There is no need to sort it.

Regards,

ravi

Re: Do I need to sort a hashed table before reading ?

Former Member — Fri, 02 Jun 2006 14:26:11 GMT

DO NOT SORT IT !!!!

A hashed table is not sorted in any way. It is organized according to a "hash" algorithm, which is a mathematical calculation.

This "hashing" provides for maximize speed of data retrival when looking for a SINGLE, UNIQUE record!!

If you have multiple records in the internal table with the same key, a hash table is NOT the way to go. In that case, use a SORTED table.

But DO NOT sort a hashed table... you will probably find performance degradation AFTER a SORT is performed on one. SAP will "realize" that the hash algorithm has been borken... and SAP will start to read the int table sequentially.

Re: Do I need to sort a hashed table before reading ?

abdul_hakim — Fri, 02 Jun 2006 14:26:32 GMT

<b>Not needed!!</b>

Cheers,

Abdul Hakim

Mark all useful answers..