diff options
Diffstat (limited to 'src/backend/storage/ipc/dsm_impl.c')
| -rw-r--r-- | src/backend/storage/ipc/dsm_impl.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/src/backend/storage/ipc/dsm_impl.c b/src/backend/storage/ipc/dsm_impl.c index 138bdec47e9..1972aecbedc 100644 --- a/src/backend/storage/ipc/dsm_impl.c +++ b/src/backend/storage/ipc/dsm_impl.c @@ -247,14 +247,17 @@ dsm_impl_posix(dsm_op op, dsm_handle handle, Size request_size, /* * Create new segment or open an existing one for attach. * - * Even though we're not going through fd.c, we should be safe against - * running out of file descriptors, because of NUM_RESERVED_FDS. We're - * only opening one extra descriptor here, and we'll close it before - * returning. + * Even though we will close the FD before returning, it seems desirable + * to use Reserve/ReleaseExternalFD, to reduce the probability of EMFILE + * failure. The fact that we won't hold the FD open long justifies using + * ReserveExternalFD rather than AcquireExternalFD, though. */ + ReserveExternalFD(); + flags = O_RDWR | (op == DSM_OP_CREATE ? O_CREAT | O_EXCL : 0); if ((fd = shm_open(name, flags, PG_FILE_MODE_OWNER)) == -1) { + ReleaseExternalFD(); if (errno != EEXIST) ereport(elevel, (errcode_for_dynamic_shared_memory(), @@ -278,6 +281,7 @@ dsm_impl_posix(dsm_op op, dsm_handle handle, Size request_size, /* Back out what's already been done. */ save_errno = errno; close(fd); + ReleaseExternalFD(); errno = save_errno; ereport(elevel, @@ -295,6 +299,7 @@ dsm_impl_posix(dsm_op op, dsm_handle handle, Size request_size, /* Back out what's already been done. */ save_errno = errno; close(fd); + ReleaseExternalFD(); shm_unlink(name); errno = save_errno; @@ -323,6 +328,7 @@ dsm_impl_posix(dsm_op op, dsm_handle handle, Size request_size, /* Back out what's already been done. */ save_errno = errno; close(fd); + ReleaseExternalFD(); if (op == DSM_OP_CREATE) shm_unlink(name); errno = save_errno; @@ -336,6 +342,7 @@ dsm_impl_posix(dsm_op op, dsm_handle handle, Size request_size, *mapped_address = address; *mapped_size = request_size; close(fd); + ReleaseExternalFD(); return true; } |