Preinstallation for an Overlay Installation

Learn how to execute an overlay installation.

Verify that your current Adaptive Server is an earlier version. In isql enter:
```
1> select @@version
2> go
```
Installing a newer version of Adaptive Server overwrites any older versions of Adaptive Server. Prior to installing make sure that your databases are error free and back up your $SYBASEdirectory, in case you must return to the original version of the software.
To ensure that your database is error free, run dbcc checkdb, dbcc checkcatalog and dbcc checkstorage prior to installing new Adaptive Server binaries including the master database.

If any of the dbcc commands reveal problems, stop here and see the Troubleshooting and Error Messages Guide for more information.
If you are installing Adaptive Server 15.5 over an existing Adaptive Server 15.0.x version then, if Java in the database feature is enabled, perform the following steps:
- Create the sybpcidb database
  The sybpcidb database stores configuration information for the PCI and all PCA components. This database is used by the installpcidb script. For example:
```
1> disk init
2> name = "sybpcidb_dev",
3> physname = "${SYBASE}/data/sybpcidb_dev.dat",
4> size = '24MB'
5> go
1> create database sybpcidb on sybpcidb_dev = 24
2> go
```
  The device and database sizes depend on the Adaptive Server page size:
  - 2k page size - 24MB
  - 4k page size - 48MB
  - 8k page size - 96MB
  - 16k pagesize - 192MB
  If you are upgrading from a 15.0.x ASE, disable the Java in the database feature before upgrading and enable again after the upgrade.
- Disable the Java in the database feature:
```
1> sp_configure 'enable java', 0
2> go
```

Note:

If you plan to use sqlupgrade utility to upgrade from a pre-15.0.x Adaptive Server, do not disable the Java in the database feature. The sqlupgrade utility will automatically disable and re-enable the Java in the database feature.