Progress
Database Administration
Guide and Reference


Connection Modes

Progress databases run in one of two connection modes: single-user or multi-user. Connection modes control how many users can access a database simultaneously.

Single-user Mode

A database running in single-user mode allows one user to access a specified database at a time. If another user is already accessing a database, you cannot connect to that database from a different Progress session. The database engine uses a lock file (.lk) to lock out other users.

Running a database in single-user mode is helpful when you perform system administration tasks that require exclusive access to the database.

Multi-user Mode

A database running in multi-user mode enables more than one user to access it simultaneously. A broker coordinates all the database requests from all the users using a single database. For example, the broker process locks the database to prevent any other broker or single-user process from opening it. Also, all users must request access from the broker to connect to the database.

Both single-user and multi-user processes can run in either interactive or batch mode. Table 1–2 compares these modes.

Table 1–2: Interactive Mode Versus Batch Mode 
Mode
Description
Interactive mode
The user interacts directly with the database.
Batch mode
Processing occurs without user interaction. Batch mode is convenient for large-scale database updates or procedures that can run unattended (at night, for example). However, multi-user batch jobs can degrade the response time for interactive users.


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