Other variables

There are a few variables that describe memory used by components not directly related to running queries or storing data:

  • Alloc_replication: Tracks the amount of memory used during replication.

  • Malloc_active_memory: Tracks memory allocated directly from the Linux OS and managed by the C runtime allocators (not SingleStore DB’s built-in memory allocators that use the Buffer Manager). The memory use here should be approximately 1-2 GBs for most workloads. Column store tables, open connections, and memory for metadata about tables, columns, etc. are the biggest consumers of memory.

  • Alloc_thread_stacks: Tracks memory used by thread stacks. SingleStore DB caches threads used to execute queries. Each thread has a 1 MB stack by default. This can be controlled by the thread_stack session variable, but it is recommended that you do not change this value. SingleStore DB will kill threads it hasn’t used for 24 hours which will free up stack memory (this can be controlled by the idle_thread_lifetime_seconds variable).