Allows you to modify the extent and snapshot allocation of
a storage area. You cannot specify RDB$SYSTEM in the change-
storage-area-clause. To change the EXTENT, SNAPSHOT ALLOCATION,
or SNAPSHOT EXTENT for RDB$SYSTEM, specify these qualifiers as
part of the change-database-options. When you specify these
options as part of the change-database-options, they will be
changed for RDB$SYSTEM but not for any other storage areas.
(B)0[mchange-storage-area-clause =
qqqqqq> [4mCHANGE[m [4mSTORAGE[m [4mAREA[m qqqqqqqq> storage-area-name qqqqqk
lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq<qqqqqqqqqqqqqqqqqqqqqqqqj
mqwqwqwqqqqqqqqqqqqqqqqqqqqqqqqqqqqq>qqqqqqqqqqqqqqqqqqqqqqwqwqwqq>
x x tq> [4mREAD_WRITE[m qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqu x x
x x tq> [4mEXTENT[m IS qw> extent-pages qqqqqqqq PAGES qwqqqqqu x x
x x x m> extension-options qqqqqqqqqqqj x x x
x x tq> [4mSNAPSHOT[m [4mALLOCATION[m IS qq> snp-pages qqq> PAGES qu x x
x x mq> [4mSNAPSHOT[m [4mEXTENT[m IS qw> extent-pages qq> PAGES qwqj x x
x x m> (extension-options) qqqqj x x
x mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq<qqqqqqqqqqqqqqqqqqqqqqqqj x
tqqqqq> [4mREAD_ONLY[m qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqu
mqqqqq> [4mWRITE_ONCE[m qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj
1 – storage-area-name
The name of the storage area that you want to modify.
2 – READ_WRITE
Used to change any read-only storage area (except the RDB$SYSTEM
storage area) to a read/write storage area.
To change a read-only RDB$SYSTEM storage area to read/write, you
must use the READ_WRITE option of the change-database-options2
clause.
3 – snp-pages
Specifies the number of pages allocated for the snapshot file.
The default is 100 pages.
4 – extent-pages
Specifies the number of pages of each extent. The default is 100
pages.
5 – extension-options
Specifies the MIN, MAX, and percent growth of each database file
extent. Enclose the parameter list in parentheses.
(B)0[mextension-options =
qqq> ( qqq> [4mMINIMUM[m OF qq> min-pages qqq> PAGES, qk
lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj
mqq> [4mMAXIMUM[m OF qq> max-pages qq> PAGES,qk
lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj
mqq> [4mPERCENT[m [4mGROWTH[m IS qqq> growth qqqq> ) qqq>
5.1 – min-pages
Specifies the minimum number of pages of each extent. The default
is 99 pages.
5.2 – max-pages
Specifies the maximum number of pages of each extent. The default
is 9,999 pages.
5.3 – growth
Specifies the percent growth of each extent. The default is 20
percent growth.
6 – READ_ONLY
Used to change any read/write storage area (except the RDB$SYSTEM
storage area) to a read-only storage area.
To change a read/write RDB$SYSTEM storage area to read-only, you
must use the READ_ONLY option of the change-database-options2
clause.
You cannot change the parameters of a read-only storage area.
You must first change the storage area to a read/write area, then
change the parameters.
Also, no write operation can be done in a read-only storage area
except a cardinality update. See the RMU/ANALYZE/CARDINALITY help
topic in the RMU help file for more information and restrictions
on updating cardinalities.
7 – WRITE_ONCE
You can use the WRITE_ONCE option to change a storage area
containing stable segmented string data to a format that can
be stored on a write-once, read-many (WORM) optical disk. A WORM
optical disk offers a relatively inexpensive way of storing large
amounts of data for read-only access compared to other storage
media.
The following restrictions apply to the WRITE_ONCE option:
o Note that you cannot write data other than segmented strings
to a write-once storage area. Oracle Rdb issues an error message
if you try to create a storage map that stores data other than
segmented strings in a write-once storage area. Storage maps
for non-segmented-string data must be removed before you can
alter a storage area to WRITE_ONCE.
o When you create a storage area on WORM media, you must specify
that the snapshot area remains on read/write media: do not
give a snapshot file the WRITE_ONCE attribute.
o If you specify the WRITE_ONCE option when storing a segmented
string, database keys are not compressed. For more information
on database key compression, see the Oracle Rdb Guide to Database
Maintenance.
o Write-once storage areas do not use SPAM pages to look for
storage space, but to assist moving data back to non-WORM
media in which SPAM pages must be built again, space is still
allocated for them. Since SPAM pages are essential in uniform
areas, Write-once storage areas cannot be of uniform format
and therefore are required to be of mixed format.
o You can use the PAGE SIZE IS clause of CREATE STORAGE AREA to
change the default page size for a storage area. To optimize
storage, always specify an even number of blocks per page.
o Rdb does not support magnetic media for storing write-once
storage areas.
o After you move a storage area to or from a WORM device,
Do a full and complete backup of your database with the
RMU/BACKUP command and start a new after-image journaling
file. For more information on backup and recovery procedures
with write-once storage areas, see the Oracle Rdb Guide to
Database Maintenance.