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AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
System administrationThese topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL OneDB™ database servers.
Administrator's GuideThe HCL OneDB™ Administrator's Guide provides the information required to administer HCL OneDB™.
Disk, memory, and process management
Shared memoryThese topics describe the content of database server shared memory, the factors that determine the sizes of shared-memory areas, and how data moves into and out of shared memory.
Concurrency controlThe database server threads that run on the same virtual processor and on separate virtual processors share access to resources in shared memory.
Shared-memory buffer locksA primary benefit of shared memory is the ability of database server threads to share access to disk pages stored in the shared-memory buffer pool. The database server maintains thread isolation while it achieves this increased concurrency through a strategy for locking the data buffers.
Types of buffer locksThe database server uses two types of locks to manage access to shared-memory buffers.
Exclusive lockA buffer is in exclusive mode, or has an exclusive lock, if a thread demands exclusive access to the buffer.

Exclusive lock

A buffer is in exclusive mode, or has an exclusive lock, if a thread demands exclusive access to the buffer.

All other thread requests that access the buffer are placed in the wait queue. When the executing thread is ready to release the exclusive lock, it wakes the next thread in the wait queue.

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