diff options
Diffstat (limited to 'src/include/postmaster/bgworker.h')
| -rw-r--r-- | src/include/postmaster/bgworker.h | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h index 8bbbeb492c9..c27b08bf1ef 100644 --- a/src/include/postmaster/bgworker.h +++ b/src/include/postmaster/bgworker.h @@ -9,17 +9,22 @@ * worker. Workers can also be registered dynamically at runtime. In either * case, the worker process is forked from the postmaster and runs the * user-supplied "main" function. This code may connect to a database and - * run transactions. Once started, it stays active until shutdown or crash; - * unless the restart interval is declared as BGW_NEVER_RESTART and the - * process exits with a return code of 1; workers that do this are - * automatically unregistered by the postmaster. + * run transactions. Workers can remain active indefinitely, but will be + * terminated if a shutdown or crash occurs. * * If the fork() call fails in the postmaster, it will try again later. Note * that the failure can only be transient (fork failure due to high load, * memory pressure, too many processes, etc); more permanent problems, like * failure to connect to a database, are detected later in the worker and dealt - * with just by having the worker exit normally. Postmaster will launch a new - * worker again later. + * with just by having the worker exit normally. A worker which exits with a + * return code of 0 will be immediately restarted by the postmaster. A worker + * which exits with a return code of 1 will be restarted after the configured + * restart interval, or never if that interval is set to BGW_NEVER_RESTART. + * The TerminateBackgroundWorker() function can be used to terminate a + * dynamically registered background worker; the worker will be sent a SIGTERM + * and will not be restarted after it exits. Whenever the postmaster knows + * that a worker will not be restarted, it unregisters the worker, freeing up + * that worker's slot for use by a new worker. * * Note that there might be more than one worker in a database concurrently, * and the same module may request more than one worker running the same (or @@ -107,6 +112,9 @@ extern BgwHandleStatus GetBackgroundWorkerPid(BackgroundWorkerHandle *handle, extern BgwHandleStatus WaitForBackgroundWorkerStartup(BackgroundWorkerHandle * handle, pid_t *pid); +/* Terminate a bgworker */ +extern void TerminateBackgroundWorker(BackgroundWorkerHandle *handle); + /* This is valid in a running worker */ extern BackgroundWorker *MyBgworkerEntry; |