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Allow concurrent-safe open() and fopen() in frontend code for Windows

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PostgreSQL uses a custom wrapper for open() and fopen() which is
concurrent-safe, allowing multiple processes to open and work on the
same file.  This has a couple of advantages:
- pg_test_fsync does not handle O_DSYNC correctly otherwise, leading to
false claims that disks are unsafe.
- TAP tests can run into race conditions when a postmaster and pg_ctl
open postmaster.pid, fixing some random failures in the buildfam.

pg_upgrade is one frontend tool using workarounds to bypass file locking
issues with the log files it generates, however the interactions with
pg_ctl are proving to be tedious to get rid of, so this is left for
later.

Author: Laurenz Albe
Reviewed-by: Michael Paquier, Kuntal Ghosh
Discussion: https://postgr.es/m/1527846213.2475.31.camel@cybertec.at
Discussion: https://postgr.es/m/16922.1520722108@sss.pgh.pa.us
This commit is contained in:
Michael Paquier 2018-09-14 10:04:14 +09:00
parent 28a8fa984c
commit 0ba06e0bfb
5 changed files with 12 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/bin/initdb/initdb.c
View File

@ -491,7 +491,15 @@ readfile(const char *path)
char *buffer;
int c;
#ifdef WIN32
/*
* On Windows, we have to open the file in text mode so that carriage
* returns are stripped.
*/
if ((infile = fopen(path, "rt")) == NULL)
#else
if ((infile = fopen(path, "r")) == NULL)
#endif
{
fprintf(stderr, _("%s: could not open file \"%s\" for reading: %s\n"),
progname, path, strerror(errno));

2
src/bin/pg_basebackup/pg_receivewal.c
View File

@ -288,7 +288,7 @@ FindStreamingStart(uint32 *tli)
snprintf(fullpath, sizeof(fullpath), "%s/%s", basedir, dirent->d_name);
fd = open(fullpath, O_RDONLY | PG_BINARY);
fd = open(fullpath, O_RDONLY | PG_BINARY, 0);
if (fd < 0)
{
fprintf(stderr, _("%s: could not open compressed file \"%s\": %s\n"),

2
src/bin/pg_verify_checksums/pg_verify_checksums.c
View File

@ -80,7 +80,7 @@ scan_file(const char *fn, BlockNumber segmentno)
int f;
BlockNumber blockno;
f = open(fn, O_RDONLY | PG_BINARY);
f = open(fn, O_RDONLY | PG_BINARY, 0);
if (f < 0)
{
fprintf(stderr, _("%s: could not open file \"%s\": %s\n"),

4
src/common/file_utils.c
View File

@ -222,7 +222,7 @@ pre_sync_fname(const char *fname, bool isdir, const char *progname)
{
int fd;
fd = open(fname, O_RDONLY | PG_BINARY);
fd = open(fname, O_RDONLY | PG_BINARY, 0);
if (fd < 0)
{
@ -283,7 +283,7 @@ fsync_fname(const char *fname, bool isdir, const char *progname)
* unsupported operations, e.g. opening a directory under Windows), and
* logging others.
*/
fd = open(fname, flags);
fd = open(fname, flags, 0);
if (fd < 0)
{
if (errno == EACCES || (isdir && errno == EISDIR))

3
src/include/port.h
View File

@ -249,11 +249,8 @@ extern bool rmtree(const char *path, bool rmtopdir);
#define O_DIRECT 0x80000000
extern int pgwin32_open(const char *, int,...);
extern FILE *pgwin32_fopen(const char *, const char *);
#ifndef FRONTEND
#define open(a,b,c) pgwin32_open(a,b,c)
#define fopen(a,b) pgwin32_fopen(a,b)
#endif
/*
* Mingw-w64 headers #define popen and pclose to _popen and _pclose. We want