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| author | Robert Haas <rhaas@postgresql.org> | 2012-06-28 12:57:22 -0400 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2012-06-28 12:57:22 -0400 |
| commit | 39715af23ae459684963c350dd69eafa2d502e7e (patch) | |
| tree | ef4fb750463f7f92f0cf180297ae23b65ad58177 | |
| parent | b0fc0df9364d2d2d17c0162cf3b8b59f6cb09f67 (diff) | |
| download | postgresql-39715af23ae459684963c350dd69eafa2d502e7e.tar.gz postgresql-39715af23ae459684963c350dd69eafa2d502e7e.zip | |
Fix broken mmap failure-detection code, and improve error message.
Per an observation by Thom Brown that my previous commit made an
overly large shmem allocation crash the server, on Linux.
| -rw-r--r-- | src/backend/port/sysv_shmem.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c index 4bbd0ec6495..20f31ed218d 100644 --- a/src/backend/port/sysv_shmem.c +++ b/src/backend/port/sysv_shmem.c @@ -419,10 +419,17 @@ PGSharedMemoryCreate(Size size, bool makePrivate, int port) */ AnonymousShmem = mmap(NULL, size, PROT_READ|PROT_WRITE, PG_MMAP_FLAGS, -1, 0); - if (AnonymousShmem == NULL) + if (AnonymousShmem == MAP_FAILED) ereport(FATAL, - (errmsg("could not map %lu bytes of anonymous shared memory: %m", - (unsigned long) AnonymousShmemSize))); + (errmsg("could not map anonymous shared memory: %m"), + (errno == ENOMEM) ? + errhint("This error usually means that PostgreSQL's request " + "for a shared memory segment exceeded available memory " + "or swap space. To reduce the request size (currently " + "%lu bytes), reduce PostgreSQL's shared memory usage, " + "perhaps by reducing shared_buffers or " + "max_connections.", + (unsigned long) AnonymousShmemSize) : 0)); /* Now we can allocate a minimal SHM block. */ allocsize = sizeof(PGShmemHeader); |