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Restore pg_pread and friends.

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Commits cf112c12 and a0dc8271 were a little too hasty in getting rid of
the pg_ prefixes where we use pread(), pwrite() and vectored variants.

We dropped support for ancient Unixes where we needed to use lseek() to
implement replacements for those, but it turns out that Windows also
changes the current position even when you pass in an offset to
ReadFile() and WriteFile() if the file handle is synchronous, despite
its documentation saying otherwise.

Switching to asynchronous file handles would fix that, but have other
complications.  For now let's just put back the pg_ prefix and add some
comments to highlight the non-standard side-effect, which we can now
describe as Windows-only.

Reported-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Discussion: https://postgr.es/m/20220923202439.GA1156054%40nathanxps13
This commit is contained in:
Thomas Munro
2022-09-29 13:12:11 +13:00
parent 3a5817695a
commit b6d8a60aba
19 changed files with 75 additions and 55 deletions
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50
src/bin/pg_test_fsync/pg_test_fsync.c
View File

@ -312,10 +312,10 @@ test_sync(int writes_per_op)
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
if (pg_pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
}
STOP_TIMER;
@ -337,10 +337,10 @@ test_sync(int writes_per_op)
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
if (pg_pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
fdatasync(tmpfile);
}
@ -359,10 +359,10 @@ test_sync(int writes_per_op)
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
if (pg_pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
@ -383,10 +383,10 @@ test_sync(int writes_per_op)
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
if (pg_pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
if (pg_fsync_writethrough(tmpfile) != 0)
die("fsync failed");
@ -415,10 +415,10 @@ test_sync(int writes_per_op)
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
if (pg_pwrite(tmpfile,
buf,
XLOG_BLCKSZ,
writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
/*
* This can generate write failures if the filesystem has
@ -480,10 +480,10 @@ test_open_sync(const char *msg, int writes_size)
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < 16 / writes_size; writes++)
if (pwrite(tmpfile,
buf,
writes_size * 1024,
writes * writes_size * 1024) !=
if (pg_pwrite(tmpfile,
buf,
writes_size * 1024,
writes * writes_size * 1024) !=
writes_size * 1024)
die("write failed");
}
@ -582,7 +582,7 @@ test_non_sync(void)
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
if (pwrite(tmpfile, buf, XLOG_BLCKSZ, 0) != XLOG_BLCKSZ)
if (pg_pwrite(tmpfile, buf, XLOG_BLCKSZ, 0) != XLOG_BLCKSZ)
die("write failed");
}
STOP_TIMER;