Sophia Scheduler is responsible for planning all background tasks depending on current system load and selected profile (redzone).

The schedule handles following tasks: garbage collection, branch compaction, node compaction, log ration, lru, anti-cache election, async reads, and so on.

Sophia has multi-thread scallable compaction. Number of active background workers (threads) can be set using scheduler.threads variable.

sp_setint(env, "scheduler.threads", 5);

Please take a look at the Compaction and Scheduler configuration sections for more details.

Compaction Configuration

Sophia compaction process is configurable via redzone. Redzone is a special value which represents current memory usage. Each redzone defines the background operations' priority, etc.

If no memory limit is set, redzone zero is used (default).

To create a new redzone, write a percent value into compaction namespace.

By default only compaction.0 and compaction.80 redzones are defined. When 80 percent of the memory usage is reached, checkpoint process starts automatically.


It is possible to start incremental asynchronous checkpointing process, which will force branch creation and memory freeing for every node in-memory index. Once a memory index log is free, files also will be automatically garbage-collected.

sp_setint(env, "scheduler.checkpoint", 0);

Procedure call is fast and does not block. scheduler.checkpoint_active and scheduler.checkpoint_lsn_last variables can be examined to see if checkpoint process is completed.

Checkpoints are automatically used to ensure a memory limit.