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Assorted bgworker-related comment fixes.

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Per gripes by Amit Kapila.
This commit is contained in:
Robert Haas
2013-08-01 12:20:31 -04:00
parent 813fb03155
commit 149e38e5ee
2 changed files with 12 additions and 12 deletions
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12
src/backend/postmaster/bgworker.c
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@@ -134,17 +134,15 @@ BackgroundWorkerShmemInit(void)
Assert(found); Assert(found);
} }
/*
* Search the postmaster's backend-private list of RegisteredBgWorker objects
* for the one that maps to the given slot number.
*/
static RegisteredBgWorker * static RegisteredBgWorker *
FindRegisteredWorkerBySlotNumber(int slotno) FindRegisteredWorkerBySlotNumber(int slotno)
{ {
slist_iter siter; slist_iter siter;
/*
* Copy contents of worker list into shared memory. Record the
* shared memory slot assigned to each worker. This ensures
* a 1-to-1 correspondence betwen the postmaster's private list and
* the array in shared memory.
*/
slist_foreach(siter, &BackgroundWorkerList) slist_foreach(siter, &BackgroundWorkerList)
{ {
RegisteredBgWorker *rw; RegisteredBgWorker *rw;
@@ -158,7 +156,7 @@ FindRegisteredWorkerBySlotNumber(int slotno)
} }
/* /*
* Notice changes to shared_memory made by other backends. This code * Notice changes to shared memory made by other backends. This code
* runs in the postmaster, so we must be very careful not to assume that * runs in the postmaster, so we must be very careful not to assume that
* shared memory contents are sane. Otherwise, a rogue backend could take * shared memory contents are sane. Otherwise, a rogue backend could take
* out the postmaster. * out the postmaster.

12
src/include/postmaster/bgworker.h
View File

@@ -6,11 +6,13 @@
* including normal transactions. * including normal transactions.
* *
* Any external module loaded via shared_preload_libraries can register a * Any external module loaded via shared_preload_libraries can register a
* worker. Then, at the appropriate time, the worker process is forked from * worker. Workers can also be registered dynamically at runtime. In either
* the postmaster and runs the user-supplied "main" function. This code may * case, the worker process is forked from the postmaster and runs the
* connect to a database and run transactions. Once started, it stays active * user-supplied "main" function. This code may connect to a database and
* until shutdown or crash. The process should sleep during periods of * run transactions. Once started, it stays active until shutdown or crash;
* inactivity. * 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.
* *
* If the fork() call fails in the postmaster, it will try again later. Note * 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, * that the failure can only be transient (fork failure due to high load,