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Database Administration
Reference : Database Startup Parameters : Alphabetical listing of database startup parameters : Schema Cache File (-cache)
Schema Cache File (-cache)
Operating system and syntax
UNIX Windows
-cache filename
Use with
Maximum value
Minimum value
Single-user default
Multi-user default
The pathname of a binary schema cache file.
Use Schema Cache File (-cache) to read the database schema from a local file instead of the database. You must have previously built the schema cache and stored it as a binary file.
To perform database activities, the OpenEdge client keeps a copy of the database schema called the schema cache in memory. By default, OpenEdge creates the schema cache by reading the database schema stored in the database file. The time required to read the schema usually is minimal; however, under the following conditions, the time required to read the schema might be unacceptable:
*If the client connects to the database over a wide-area network (WAN)
*When a large number of clients connect to a database simultaneously, for example, after a database shutdown or crash
Connection time depends on several factors, including schema size.
To reduce connection time, OpenEdge lets you store the schema cache as a binary file, called a schema cache file, on a local disk. The client can then read the schema directly from the schema cache file.
To write the schema cache file, you build the desired schema cache and save it to a binary file using the ABL SAVE CACHE statement. The schema cache file is portable across systems, so you can create the file once and distribute it across a heterogeneous network of systems. For information on building and saving the schema cache file, see OpenEdge Development: Programming Interfaces.
If you specify schema cache file (-cache) when you connect to a database and the local schema is valid, the AVM reads the schema from the local file instead of from the database. The schema cache is valid if the time stamp of the schema cache file matches the time stamp in the database master block. If the time stamps do not match, or for some reason the AVM cannot read the file, the AVM issues a warning message and reads the schema from the database.
Note: If you are generating the local binary schema cache, do not connect to the database using Trigger Location (-trig) and Schema Cache File (-cache) together.