To Alter a column definition

[Patrick]

When re-creating the table make sure to use "options compress=yes;"

Network throughput and Disk I/O are very often the bottleneck and I've seen it more than once that using character compression for a table can speed up things quite a bit - especially if there are a lot of character variables with "empty space".

[Peter_C · Accepted solution]

Augusto

as you know, you are in a difficult position. You cannot increase the width for new values in $30 column, without rewriting the whole table, except....

If you "close" the old table and start writing new rows to a new table of the same structure, which has that column defined as $50.

When analysing, read both "old" and "new" through a view (just make sure that the wider definition is found first on the concatenation.

PROC SQL might provide the most "transparent" join of the tables (as it would allow an sql query optimiser to reach through an sql view, to any indexes defined for "old" and "new". This is not possible through a data step view).

hope this is useful

peterC    

[Augusto]

Hi Peter. I hadn't thought about that. You are sure I still have a way out. This was very useful indeed.

Thanks all.