SHMSTORE

The SHMSTORE function stores an object in a named shared memory location, i.e. in a memory location independent of a given execution context.

The call will fail if the calling script is not currently holding a mutex (in a call to MUTEX). The call will have no effect if the named memory location was already set by a previous call to SHMSTORE.

In order to overwrite a shared memory location, its content must first be cleared by storing NULL.

If the calling script currently holds a mutex, this mutex will be associated with the shared memory location, the same mutex will have to be held when retrieving the content of the memory location via SHMLOAD.

The shm.ttl configuration, in millisecond, allow you to tune the retention time in memory. Default value is one hour. Tip: you can call SHMLOAD in a runner with a period shorter than shm.ttl if you want to keep value in memory indefinitely.