Changeset: aa2e3065be7e for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=aa2e3065be7e
Modified Files:
gdk/gdk_bbp.c
gdk/gdk_heap.c
Branch: Feb2013
Log Message:
For memory mapped files, create a backup copy before widening.
This solves a problem that we don't control what's in the actual file
until the next commit happens, so a crash might otherwise leave the
file (and the database) in an inconsistent state.
diffs (118 lines):
diff --git a/gdk/gdk_bbp.c b/gdk/gdk_bbp.c
--- a/gdk/gdk_bbp.c
+++ b/gdk/gdk_bbp.c
@@ -3161,8 +3161,14 @@ do_backup(const char *srcdir, const char
int ret = 0;
/* direct mmap is unprotected (readonly usage, or has WAL
- * protection) */
- if (h->storage != STORE_MMAP) {
+ * protection); however, if we're backing up for subcommit
+ * and a backup already exists in the main backup directory
+ * (see GDKupgradevarheap), move the file */
+ if (subcommit && file_exists(BAKDIR, nme, extbase)) {
+ assert(h->storage == STORE_MMAP);
+ if (file_move(BAKDIR, SUBDIR, nme, extbase))
+ return -1;
+ } else if (h->storage != STORE_MMAP) {
/* STORE_PRIV saves into X.new files. Two cases could
* happen. The first is when a valid X.new exists
* because of an access change or a previous
diff --git a/gdk/gdk_heap.c b/gdk/gdk_heap.c
--- a/gdk/gdk_heap.c
+++ b/gdk/gdk_heap.c
@@ -394,6 +394,20 @@ HEAPshrink(Heap *h, size_t size)
return -1;
}
+/* returns 1 if the file exists */
+static int
+file_exists(const char *dir, const char *name, const char *ext)
+{
+ long_str path;
+ struct stat st;
+ int ret;
+
+ GDKfilepath(path, dir, name, ext);
+ ret = stat(path, &st);
+ IODEBUG THRprintf(GDKstdout, "#stat(%s) = %d\n", path, ret);
+ return (ret == 0);
+}
+
int
GDKupgradevarheap(COLrec *c, var_t v, int copyall)
{
@@ -407,6 +421,7 @@ GDKupgradevarheap(COLrec *c, var_t v, in
#endif
size_t i, n;
size_t savefree;
+ const char *filename;
assert(c->heap.parentid == 0);
assert(width != 0);
@@ -418,11 +433,65 @@ GDKupgradevarheap(COLrec *c, var_t v, in
}
assert(c->width < width);
assert(c->shift < shift);
+
/* if copyall is set, we need to convert the whole heap, since
* we may be in the middle of an insert loop that adjusts the
* free value at the end; otherwise only copy the area
* indicated by the "free" pointer */
n = (copyall ? c->heap.size : c->heap.free) >> c->shift;
+
+ /* for memory mapped files, create a backup copy before widening
+ *
+ * this solves a problem that we don't control what's in the
+ * actual file until the next commit happens, so a crash might
+ * otherwise leave the file (and the database) in an
+ * inconsistent state
+ *
+ * also see do_backup in gdk_bbp.c */
+ filename = strrchr(c->heap.filename, DIR_SEP);
+ if (filename == NULL)
+ filename = c->heap.filename;
+ else
+ filename++;
+ if (c->heap.storage == STORE_MMAP && !file_exists(BAKDIR, filename,
NULL)) {
+ int fd;
+ ssize_t ret = 0;
+ size_t size = n << c->shift;
+ const char *base = c->heap.base;
+
+ /* first save heap in file with extra .tmp extension */
+ if ((fd = GDKfdlocate(c->heap.filename, "wb", "tmp")) < 0)
+ return GDK_FAIL;
+ while (size > 0) {
+ ret = write(fd, base, (unsigned) MIN(1 << 30, size));
+ if (ret < 0)
+ size = 0;
+ size -= ret;
+ base += ret;
+ }
+ if (ret < 0 ||
+#if defined(NATIVE_WIN32)
+ _commit(fd) < 0 ||
+#elif defined(HAVE_FDATASYNC)
+ fdatasync(fd) < 0 ||
+#elif defined(HAVE_FSYNC)
+ fsync(fd) < 0 ||
+#endif
+ close(fd) < 0) {
+ /* something went wrong: abandon ship */
+ close(fd);
+ GDKunlink(BATDIR, c->heap.filename, "tmp");
+ return GDK_FAIL;
+ }
+ /* move tmp file to backup directory (without .tmp
+ * extension) */
+ if (GDKmove(BATDIR, c->heap.filename, "tmp", BAKDIR, filename,
NULL) < 0) {
+ /* backup failed */
+ GDKunlink(BATDIR, c->heap.filename, "tmp");
+ return GDK_FAIL;
+ }
+ }
+
savefree = c->heap.free;
if (copyall)
c->heap.free = c->heap.size;
_______________________________________________
checkin-list mailing list
[email protected]
https://www.monetdb.org/mailman/listinfo/checkin-list
