Retry in FileRead and FileWrite if Windows returns ERROR_NO_SYSTEM_RESOURCES.

Also add a retry for Unixen returning EINTR, which hasn't been reported
as an issue but at least theoretically could be.  Patch by Qingqing Zhou,
some minor adjustments by me.
This commit is contained in:
Tom Lane 2005-12-01 20:24:49 +00:00
parent 64c09adea7
commit eeae797d33

View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.115.4.1 2005/08/07 18:47:38 tgl Exp $
* $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.115.4.2 2005/12/01 20:24:49 tgl Exp $
*
* NOTES:
*
@ -983,11 +983,41 @@ FileRead(File file, char *buffer, int amount)
if (returnCode < 0)
return returnCode;
retry:
returnCode = read(VfdCache[file].fd, buffer, amount);
if (returnCode > 0)
if (returnCode >= 0)
VfdCache[file].seekPos += returnCode;
else
{
/*
* Windows may run out of kernel buffers and return "Insufficient
* system resources" error. Wait a bit and retry to solve it.
*
* It is rumored that EINTR is also possible on some Unix filesystems,
* in which case immediate retry is indicated.
*/
#ifdef WIN32
DWORD error = GetLastError();
switch (error)
{
case ERROR_NO_SYSTEM_RESOURCES:
pg_usleep(1000L);
errno = EINTR;
break;
default:
_dosmaperr(error);
break;
}
#endif
/* OK to retry if interrupted */
if (errno == EINTR)
goto retry;
/* Trouble, so assume we don't know the file position anymore */
VfdCache[file].seekPos = FileUnknownPos;
}
return returnCode;
}
@ -1007,6 +1037,7 @@ FileWrite(File file, char *buffer, int amount)
if (returnCode < 0)
return returnCode;
retry:
errno = 0;
returnCode = write(VfdCache[file].fd, buffer, amount);
@ -1014,10 +1045,34 @@ FileWrite(File file, char *buffer, int amount)
if (returnCode != amount && errno == 0)
errno = ENOSPC;
if (returnCode > 0)
if (returnCode >= 0)
VfdCache[file].seekPos += returnCode;
else
{
/*
* See comments in FileRead()
*/
#ifdef WIN32
DWORD error = GetLastError();
switch (error)
{
case ERROR_NO_SYSTEM_RESOURCES:
pg_usleep(1000L);
errno = EINTR;
break;
default:
_dosmaperr(error);
break;
}
#endif
/* OK to retry if interrupted */
if (errno == EINTR)
goto retry;
/* Trouble, so assume we don't know the file position anymore */
VfdCache[file].seekPos = FileUnknownPos;
}
return returnCode;
}