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Rollback usage query

P: n/a
Hi all,

Given a rollback segment with storage as follows :
Initial Extent 5 MB
Next Extent 5 MB
Min Extents 20

Does this mean that every time a transaction uses this rollback segment it
allocates 100 MB ?
Does this mean that if there are two transactions using this rollback
segment, 200 MB is required ?

Thanks,
Alice
Jul 19 '05 #1
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2 Replies


P: n/a
No. A transaction will only use as much space as it requires.

The rollback segment tablespace is just like any other tablespace (as
far as storage is concerned). Therefore it will allocate storage in
multiples of database blocks (db_block_size).

A rollback segment that has 20 extents of 5Mb each has 100Mb available
for use by any number of transactions concurrently.

Matt

"Alice" <al***@reply-to-group.com> wrote in message news:<40********@news.tm.net.my>...
Hi all,

Given a rollback segment with storage as follows :
Initial Extent 5 MB
Next Extent 5 MB
Min Extents 20

Does this mean that every time a transaction uses this rollback segment it
allocates 100 MB ?
Does this mean that if there are two transactions using this rollback
segment, 200 MB is required ?

Thanks,
Alice

Jul 19 '05 #2

P: n/a
Thank Matt.

Regards,
Alice

"Matt" <mc***@hotmail.com> wrote in message
news:cf**************************@posting.google.c om...
No. A transaction will only use as much space as it requires.

The rollback segment tablespace is just like any other tablespace (as
far as storage is concerned). Therefore it will allocate storage in
multiples of database blocks (db_block_size).

A rollback segment that has 20 extents of 5Mb each has 100Mb available
for use by any number of transactions concurrently.

Matt

"Alice" <al***@reply-to-group.com> wrote in message

news:<40********@news.tm.net.my>...
Hi all,

Given a rollback segment with storage as follows :
Initial Extent 5 MB
Next Extent 5 MB
Min Extents 20

Does this mean that every time a transaction uses this rollback segment it allocates 100 MB ?
Does this mean that if there are two transactions using this rollback
segment, 200 MB is required ?

Thanks,
Alice

Jul 19 '05 #3

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