Troubleshooting DB2 installation errors often involves examining log files generated during the installation process. Log files contain valuable information about errors, warnings, and other diagnostic messages, aiding in identifying and resolving installation issues. 

Enabling monitoring tools to capture SQL performance metrics allows the DB2 administrator to identify poorly performing queries during peak hours. These tools can provide insights into various metrics such as execution time, I/O operations, and locking behavior, enabling the administrator to pinpoint the cause of slow query performance. Increasing hardware resources or restarting the DB2 instance may provide temporary relief but may not address the root cause of the issue. Disabling unnecessary applications can reduce system load but may not directly address SQL performance concerns. 

Scrollable cursors in DB2 offer the advantage of fetching rows in both forward and backward directions. This is useful when navigating through large result sets, as it enables efficient data retrieval and manipulation. By using a scrollable cursor, developers can easily move back and forth within the result set without re-executing the query. This feature enhances application performance and user experience, especially in scenarios where users need to browse through extensive data sets. 

Data compression in DB2 works by identifying and removing redundant information within the dataset. This can include eliminating duplicate records, reducing unused space, or removing any unnecessary data that might be present, ultimately leading to a reduction in the overall size of the data stored in the database. 

Visual Explain in DB2 is a tool used to provide a graphical representation of the query execution plans generated by the DB2 Optimizer. It helps database administrators and developers understand how queries are processed and identify potential performance bottlenecks. 

During the IMPORT process in DB2, the DELIMITER clause is used to specify the character that separates the fields in the data file being imported. This is crucial for accurately parsing the data and loading it into the appropriate columns in the database table. Specifying the correct delimiter ensures that the data is imported correctly and maintains its integrity. 

In DB2, a table defines the data of a database object. It holds the actual data organized in rows and columns, each column representing a different attribute or field, and each row representing a record or tuple. The structure of a table includes the column names, data types, constraints, and other properties. Thus, it defines how the data is stored and organized within the database. 

BLOB (Binary Large Object) data type is commonly used in DB2 for storing binary data, such as images, audio files, and video files. Unlike character data types like CHAR and VARCHAR, BLOB is specifically designed to efficiently handle binary data without any character set conversions or size limitations. 

The ROLLFORWARD command in DB2 is used to apply logged changes to the database that have occurred since the last backup was taken. It brings the database to a specified point-in-time, ensuring that all committed transactions are reflected in the database, thus maintaining data consistency. 

The configuration file in DB2 that stores database connection information is the db2cli.ini file. This file contains details such as database aliases, hostnames, ports, and other connection parameters necessary for establishing connections to databases. It plays a crucial role in configuring and managing database connections within DB2. 

The correct option is COUNT() with GROUP BY. COUNT() is used to count the number of rows, and GROUP BY is used to group the results by a specific column, in this case, the customer. This combination allows the data analyst to calculate the total number of orders placed by each customer. SUM() with WHERE clause calculates the total sum based on a condition, AVG() with DISTINCT calculates the average of distinct values, and MAX() with HAVING clause filters groups based on a condition after grouping. 

DB2 supports fine-grained access control by enabling administrators to specify permissions at a granular level, such as granting read-only access to certain tables or allowing specific users to modify particular rows.