From 68e7e973d22274a089ce95200b3782f514f6d2f8 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 29 Apr 2018 16:02:45 -0400 Subject: [PATCH] Get more info about Windows can't-reattach-to-shared-memory errors. Commit 63ca350ef neglected to probe the state of things *before* the VirtualFree call, which now looks like it might be interesting. Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us --- src/backend/port/win32_shmem.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/src/backend/port/win32_shmem.c b/src/backend/port/win32_shmem.c index d431e0d036..e724b3ef1a 100644 --- a/src/backend/port/win32_shmem.c +++ b/src/backend/port/win32_shmem.c @@ -388,10 +388,18 @@ PGSharedMemoryReAttach(void) { PGShmemHeader *hdr; void *origUsedShmemSegAddr = UsedShmemSegAddr; + MEMORY_BASIC_INFORMATION previnfo; + DWORD queryerr; Assert(UsedShmemSegAddr != NULL); Assert(IsUnderPostmaster); + /* Preliminary probe of region we intend to release */ + if (VirtualQuery(UsedShmemSegAddr, &previnfo, sizeof(previnfo)) != 0) + queryerr = 0; + else + queryerr = GetLastError(); + /* * Release memory region reservation that was made by the postmaster */ @@ -405,12 +413,20 @@ PGSharedMemoryReAttach(void) DWORD maperr = GetLastError(); MEMORY_BASIC_INFORMATION info; + if (queryerr == 0) + elog(LOG, "VirtualQuery(%p) before free reports region of size %zu, base %p, has state 0x%lx", + UsedShmemSegAddr, previnfo.RegionSize, + previnfo.AllocationBase, previnfo.State); + else + elog(LOG, "VirtualQuery(%p) before free failed: error code %lu", + UsedShmemSegAddr, queryerr); + if (VirtualQuery(UsedShmemSegAddr, &info, sizeof(info)) != 0) - elog(LOG, "VirtualQuery(%p) reports region of size %zu, base %p, has state 0x%lx", + elog(LOG, "VirtualQuery(%p) after free reports region of size %zu, base %p, has state 0x%lx", UsedShmemSegAddr, info.RegionSize, info.AllocationBase, info.State); else - elog(LOG, "VirtualQuery(%p) failed: error code %lu", + elog(LOG, "VirtualQuery(%p) after free failed: error code %lu", UsedShmemSegAddr, GetLastError()); elog(FATAL, "could not reattach to shared memory (key=%p, addr=%p): error code %lu",