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Further effort at preventing memory map dump from affecting the results.

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Rather than elog'ing immediately, push the map data into a preallocated
StringInfo.  Perhaps this will prevent some of the mid-operation
allocations that are evidently happening now.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us
This commit is contained in:
Tom Lane 2018-04-30 16:19:51 -04:00
parent b04ebca6cd
commit ce07aff48f
1 changed files with 23 additions and 11 deletions
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34
src/backend/port/win32_shmem.c
View File

@ -12,6 +12,7 @@
*/ */
#include "postgres.h" #include "postgres.h"
#include "lib/stringinfo.h"
#include "miscadmin.h" #include "miscadmin.h"
#include "storage/dsm.h" #include "storage/dsm.h"
#include "storage/ipc.h" #include "storage/ipc.h"
@ -54,13 +55,17 @@ mi_state(DWORD code)
return "???"; return "???";
} }
/*
* Append memory dump to buf. To avoid affecting the memory map mid-run,
* buf should be preallocated to be bigger than needed.
*/
static void static void
dumpmem(const char *reason) dumpmem(StringInfo buf, const char *reason)
{ {
char *addr = 0; char *addr = 0;
MEMORY_BASIC_INFORMATION mi; MEMORY_BASIC_INFORMATION mi;
elog(LOG, "%s memory map", reason); appendStringInfo(buf, "%s memory map:", reason);
do do
{ {
memset(&mi, 0, sizeof(mi)); memset(&mi, 0, sizeof(mi));
@ -68,12 +73,13 @@ dumpmem(const char *reason)
{ {
if (GetLastError() == ERROR_INVALID_PARAMETER) if (GetLastError() == ERROR_INVALID_PARAMETER)
break; break;
elog(LOG, "VirtualQuery failed: %lu", GetLastError()); appendStringInfo(buf, "\nVirtualQuery failed: %lu", GetLastError());
break; break;
} }
elog(LOG, "0x%p+0x%p %s (alloc 0x%p) %s", appendStringInfo(buf, "\n0x%p+0x%p %s (alloc 0x%p) %s",
mi.BaseAddress, (void *) mi.RegionSize, mi.BaseAddress, (void *) mi.RegionSize,
mi_type(mi.Type), mi.AllocationBase, mi_state(mi.State)); mi_type(mi.Type), mi.AllocationBase,
mi_state(mi.State));
addr += mi.RegionSize; addr += mi.RegionSize;
} while (addr > 0); } while (addr > 0);
} }
@ -442,11 +448,16 @@ PGSharedMemoryReAttach(void)
{ {
PGShmemHeader *hdr; PGShmemHeader *hdr;
void *origUsedShmemSegAddr = UsedShmemSegAddr; void *origUsedShmemSegAddr = UsedShmemSegAddr;
StringInfoData buf;
Assert(UsedShmemSegAddr != NULL); Assert(UsedShmemSegAddr != NULL);
Assert(IsUnderPostmaster); Assert(IsUnderPostmaster);
dumpmem("before VirtualFree"); /* Ensure buf is big enough that it won't grow mid-operation */
initStringInfo(&buf);
enlargeStringInfo(&buf, 128 * 1024);
dumpmem(&buf, "before VirtualFree");
/* /*
* Release memory region reservation that was made by the postmaster * Release memory region reservation that was made by the postmaster
@ -455,20 +466,19 @@ PGSharedMemoryReAttach(void)
elog(FATAL, "failed to release reserved memory region (addr=%p): error code %lu", elog(FATAL, "failed to release reserved memory region (addr=%p): error code %lu",
UsedShmemSegAddr, GetLastError()); UsedShmemSegAddr, GetLastError());
dumpmem("after VirtualFree"); dumpmem(&buf, "after VirtualFree");
hdr = (PGShmemHeader *) MapViewOfFileEx(UsedShmemSegID, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0, UsedShmemSegAddr); hdr = (PGShmemHeader *) MapViewOfFileEx(UsedShmemSegID, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0, UsedShmemSegAddr);
if (!hdr) if (!hdr)
{ {
DWORD maperr = GetLastError(); DWORD maperr = GetLastError();
dumpmem("after failed MapViewOfFileEx"); dumpmem(&buf, "after failed MapViewOfFileEx");
elog(LOG, "%s", buf.data);
elog(FATAL, "could not reattach to shared memory (key=%p, addr=%p): error code %lu", elog(FATAL, "could not reattach to shared memory (key=%p, addr=%p): error code %lu",
UsedShmemSegID, UsedShmemSegAddr, maperr); UsedShmemSegID, UsedShmemSegAddr, maperr);
} }
else
dumpmem("after MapViewOfFileEx");
if (hdr != origUsedShmemSegAddr) if (hdr != origUsedShmemSegAddr)
elog(FATAL, "reattaching to shared memory returned unexpected address (got %p, expected %p)", elog(FATAL, "reattaching to shared memory returned unexpected address (got %p, expected %p)",
hdr, origUsedShmemSegAddr); hdr, origUsedShmemSegAddr);
@ -476,6 +486,8 @@ PGSharedMemoryReAttach(void)
elog(FATAL, "reattaching to shared memory returned non-PostgreSQL memory"); elog(FATAL, "reattaching to shared memory returned non-PostgreSQL memory");
dsm_set_control_handle(hdr->dsm_control); dsm_set_control_handle(hdr->dsm_control);
pfree(buf.data);
UsedShmemSegAddr = hdr; /* probably redundant */ UsedShmemSegAddr = hdr; /* probably redundant */
} }