Restoring differential backups from SQL Server - sql-server

Question

I have a strange problem. I have a database, called restorelogs.
An autobackup script do a full backup, and after that, in every 3 hours a differential backup.
Next day do a full again, and then the diffs again, and so on.
No i want to write a script, what is restore this files int the restorelogs database.
From php I am using these sql queries through sqlsrv:
USE master;
ALTER DATABASE restorelogs SET MULTI_USER WITH ROLLBACK IMMEDIATE;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307151435.bak' WITH REPLACE, NORECOVERY;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307151745diff.bak' WITH FILE= 1, REPLACE, NORECOVERY;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307152045diff.bak' WITH FILE= 1, REPLACE, NORECOVERY;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307152345diff.bak' WITH FILE= 1, REPLACE, NORECOVERY;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307160245diff.bak' WITH FILE= 1, REPLACE, NORECOVERY;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307160545diff.bak' WITH FILE= 1, REPLACE, NORECOVERY;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307160845diff.bak' WITH FILE= 1, REPLACE, NORECOVERY;
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307161145diff.bak' WITH FILE= 1, REPLACE, RECOVERY;
And now will comes the interesting part of the game.
If I copy these queries into SQL Server Management Studio, and run it, it works fine. There are the tables, no error messages, everything is all right.
BUT. When I try to do it from php, the database leave in restoring mode.
As I read through a lot of pages, I understood, the last query need to include the RECOVERY option to recover the database (I also try to not use the REPLACE, just at the first query).
How can it happens?
Please help me, what do i wrong.
UPDATE: Based on Adam comment: i exactly try to do that. I collect the backup files, and use the first (full), with NORECOVERY, REPLACE, and the last WITH RECOVERY.
This is what i try:
function pushToDatabase($files) {
$dbh = new Database();
$dbh->query("USE master");
pre($dbh->errorInfo(), 0);
$cnt = count($files);
$i = 0;
foreach ($files as $file) {
$withFile = '';
$option = '';
$moves = '';
if ($i == 0) {
//restoreFromDisk($file);
//truncateDatabase();
$option = " NORECOVERY, REPLACE";
} else {
$option = " RECOVERY";
}
if ($i > 0) {
$withFile = " FILE=1, ";
}
if ($i == 0 || $i == count($files) - 1) {
$sql = "RESTORE DATABASE " . DB_NAME . " FROM DISK = '" . $file . "' WITH " . $withFile . $option . ";";
echo $sql . "<br />";
$dbh->exec($sql);
pre($dbh->errorInfo(), 0);
}
$i++;
}
$sql = "RESTORE DATABASE " . DB_NAME . " WITH RECOVERY;";
$dbh->exec($sql);
pre($dbh->errorInfo(), 0);
echo $sql . "<br />";
die("NOW WE ARE DONE!");
}
The first statement is running without any problems:
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307151435.bak' WITH NORECOVERY, REPLACE;
But after this, when i want to restore the last diff file:
RESTORE DATABASE restorelogs FROM DISK = 'D:/Apache/htdocs/logreader/extracts/SRO_VT_LOG201307161145diff.bak' WITH FILE=1, RECOVERY;
i've get back an error message:
[Microsoft][SQL Server Native Client 10.0][SQL Server]A previous restore operation was interrupted and did not complete processing on file 'Log_DB_Data'. Either restore the backup set that was interrupted or restart the restore sequence.'
And the database state leaves in restoring mode.
I've also tried to play with the RESTORE FILELISTONLY, and moving the files into the right place. I could do that, but after that i can not recover the differential backup.
function restoreFromDisk($file) {
$sql = "RESTORE FILELISTONLY FROM DISK = '" . $file . "'";
$res = dbQuery($sql);
$option = ' ,REPLACE, RECOVERY';
while ($row = dbFetchAssoc($res)) {
if ($row["LogicalName"] == "Log_DB_Data") {
$move[] = " MOVE '" . $row["LogicalName"] . "' TO '" . MSSQL_DATA_PATH . "resetlogs.mdf'";
} else {
$move[] = " MOVE '" . $row["LogicalName"] . "' TO '" . MSSQL_DATA_PATH . "resetlogs.ldf'";
}
}
$moves = join(",", $move);
$sql = "RESTORE DATABASE " . DB_NAME . " FROM DISK = '" . $file . "' WITH " . $moves . $option . ";";
dbQuery($sql);
echo $sql . "<br />";
$sql = "RESTORE DATABASE " . DB_NAME . " WITH RECOVERY;";
dbQuery($sql);
echo $sql . "<br />";
}

Answer 1

You should be setting the database to single user, if there is the potential for users to be connected (and if it is okay to kill their sessions). Since you are restoring the database, I would think that it is okay. You will need to specify the replace option on the full backup restoration. Also you only need to restore the latest differential backup (using with recovery), as it will contain all the changes since the last full backup. It should also be noted that this restore will not include transactions that have occurred since the last differential backup.
I would think about using log backups every 3 hours. This will have less impact on your system and will allow the log to truncate (if you are in full recovery). In this restore scenario, you will need the full backup and all the log backups, with the last option specifying with recovery.

Answer 2

A different approach would be to write your SQL Script to a temp file, then use osql to execute it as a script. Of course this assumes that you're running on a machine that osql installed.
osql -E -S <server> -d master -i <sql file>