名称 | 描述 | 运行一个PG实例需要的设置 | Oracle |
SHMMAX | Maximum size of shared memory segment (bytes) | at least 1kB, but the default is usually much higher | 这个值的设置应该大于SGA_MAX_TARGET或MEMORY_MAX_TARGET的值 |
SHMMIN | Minimum size of shared memory segment (bytes) | 1 | |
SHMALL | Total amount of shared memory available (pages) | ceil(SHMMAX/PAGE_SIZE) plus room for other applications | 应该小于系统物理内存，大于服务器上所有oracle数据库的SGA总和。 建议设置为物理内存 / page_size（getconf PAGE_SIZE） |
SHMSEG | Maximum number of shared memory segments per process | only 1 segment is needed, but the default is much higher | |
SHMMNI | Maximum number of shared memory segments system-wide | like SHMSEG plus room for other applications | |
SEMMNI | Maximum number of semaphore identifiers (i.e., sets) | at least ceil((max_connections + autovacuum_max_workers + max_worker_processes + 5) / 16) plus room for other applications | |
SEMMNS | Maximum number of semaphores system-wide | ceil((max_connections + autovacuum_max_workers + max_worker_processes + 5) / 16) * 17plus room for other applications | |
SEMMSL | Maximum number of semaphores per set | at least 17 | |
SEMMAP | Number of entries in semaphore map | see text | |
SEMVMX | Maximum value of semaphore | at least 1000 (The default is often 32767; do not change unless necessary) |