Sybase Adaptive Server Anywhere - Page 119

Chapter 4 Database Administration Utilities
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Omit Watcom SQL compatibility views (–k) By default, database
creation generates the views SYS.SYSCOLUMNS and SYS.SYSINDEXES
for compatibility with system tables that were available in Watcom SQL
(versions 4 and earlier of this software). These views will conflict with the
Sybase Adaptive Server Enterprise compatibility views
dbo.syscolumns and
dbo.sysindexes unless the -c case sensitivity command-line switch is used.
List the available collating sequences (–l) dbinit lists the available
collating sequences and then stops. No database is created. The list of
available collating sequences is automatically presented in Sybase Central
Create Database wizard.
Use a transaction log mirror (–m) A transaction log mirror is an
identical copy of a transaction log, usually maintained on a separate device,
for greater protection of your data. By default, Adaptive Server Anywhere
does not use a mirrored transaction log.
Do not use a transaction log (–n) Creating a database without a
transaction log saves disk space. The transaction log is required for data
replication and provides extra security for database information in case of
media failure or system failure. Databases that do not use transaction logs
typically run slower than databases that use transaction logs.
Log output messages to file (–o) Write output messages to the named
file.
Page size (–p) The page size for a database can be (in bytes) 1024, 2048,
4096, 8192, 16384, or 32768, with 2048 being the default. Any other value
for the size will be changed to the next larger size.
Large databases usually benefit from a larger page size. For example, the
number of I/O operations required to scan a table is generally lower, as a
whole page is read in at a time. Also, the number of levels in an index may
be reduced as more entries can be stored on each page.
However, there are additional memory requirements for large page sizes.
Also, the maximum number of rows stored on a page is 255, so that tables
with small rows will not fill each page. For example, with 8 kb pages the
average row size must be at least 32 bytes to fully use each page. You should
only use page sizes of 16 kb or 32 kb in productions systems when you can
be sure that a large database server cache is always available, and when you
have investigated the memory and disk space costs and the performance
benefits.
Operate quietly (–q) Do not display output messages. This option is
available only from the command-line utility.