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Hi all,
I know that the DBA handbook advises that a zero PCTINCREASE on tablespaces. Our System, RBS and Data tablespaces have a PCTINCREASE of 50 - are these the defaults. Should I be concerned? Should/Can I change them?
I believe our consultant set them up that way but I'm not sure why.
I believe the default is 50. You need not be concerned, and yes, you can change them.
Zero is better since you get uniform extent size, uniniform extent size leads to freespace fragmentation
could it be that our consultant set up the system, rbs, temp and data tablespaces with the default b/c he wanted to allow those tablespaces to extend? Is it recommended to change it to 0?
PCTINCREASE doesn't really have anything to do with tablespaces extending.
PCTINCREASE deals with the segments inside the tablespace. For example, if you have a table that has a next extent of 10K and PCTINCREASE is set to 50, the next-next extent would be 15K. The next-next-next extent would be 22.5K, etc.
If your PCTINCREASE is set to 0, all extents would be 10K, thus uniform extent sizes.
I like to set the default PCTINCREASE at 1 for the tablespace and then all the objects have a pctincrease of 0. This way, I can tell when my developers sneak a table in without sizing it correctly and don't have to worry about the table extending out really quickly.
A non zero value will ensure that tablespace coalesce happens as and when smon wakes up.But the problem with 0 is that you have to manully coalesce the tablespace.
for temp and rbs keep pctincrease as zero .for all others make it 1.
is is better in the long run to have a script to coalesce your tablespaces instead of having to deal with the non-uniform extent sizes from the pctincrease?
If you have uniform extents you will never have to coalesce that is why when pctincrease is zero SMON doesnt coalesce the extents because simply there is no need to.
You create the segments with pctincrease as zero and for tablespace 1.