How to find blocksize of a able in teradata?

Database

How to find blocksize of a able in teradata?

Hi All,

I am newbie to teradata and looking for finding blocksize of a table,i had knoweldge abt ferret utility but it does not give me exactly what I am looking for .

rgds,
Viswa
6 REPLIES

Re: How to find blocksize of a able in teradata?

Hi Vishwa,

Blocksize in teradata is defined in terms of sectors in dbs control parameter.
I think it is Permdballocation ( just refer to the dbs control portion in the doc).
for example if u see the above relevant parameter defines as 256 sectors the 256*512bytes= bytes and divide that by 1024 will give u the block size. This is system wide.
Also in teradata u can over rule this system wide block size value by allocating it at the time of creating a table. So u can create mutiple tables with diff blocksizes...

regards
TERADATA_DBA

Re: How to find blocksize of a able in teradata?

I am a newbie in Teradata.

Does it make any difference in initial size if a table is just created with one column VS multiple columns and does not contain any data?

Thanks

Re: How to find blocksize of a able in teradata?

No, there is no difference, as Teradata doesn't pre-allocate any data blocks for table, it acquires data blocks for tables when, it actually needs to insert data into table. I couldn’t remember exactly, but I think, it is slightly different from Oracle, where we can assign some initial blocks (or INITIAL or Segment) at the time of table creation.

Re: How to find blocksize of a able in teradata?

Thanks for your valueable answer.

Does TRUNCATE or similar command in Teradata has the same effect?

What I mean is if given the 3 scenarios

1. I create a table fresh with one column

OR

2. I create a table fresh with several columns

OR

3. I reset the highwater mark of a table by issuing a truncate or a similar command on a table which was previously filled with data

Q : Does the size of table would remain same in 3rd scenario too? (If I am not wrong you have already answered the scenario 1 & 2).

Your answer would be appericated.

Thanks

Re: How to find blocksize of a able in teradata?

Teradata does not have a TRUNCATE statement or any notion of a "highwater mark", but you may delete a table's entire contents using the DELETE statement without any WHERE condition. The resulting disk space usage would be the same as in the case of a freshly created empty table.

Re: How to find blocksize of a able in teradata?

Thanks for your reply.

That's very good to know.