Ticket #5946: mythtv-5946-fix_database_utf8_conversion_corruption.patch

libs/libmythtv/dbcheck.cpp

@@ -18 +18 @@
 #define MINIMUM_DBMS_VERSION 5,0,15
 
 /// This is the DB schema version expected by the running MythTV instance.
-const QString currentDatabaseVersion = "1224";
+const QString currentDatabaseVersion = "1225";
 
 static bool UpdateDBVersionNumber(const QString &newnumber);
 static bool performActualUpdate(
@@ -4312 +4312 @@
             return false;
     }
 
+    if (dbver == "1224")
+    {
+        // Fix data corruption caused by a data conversion issue in the
+        // original implementation of the 1215-1216 database upgrade
+        MSqlQuery peopleQuery(MSqlQuery::InitCon());
+        peopleQuery.prepare("SELECT person FROM people "
+                            " WHERE LENGTH(name) = 128;");
+        if (peopleQuery.exec() && peopleQuery.isActive() &&
+            peopleQuery.size() > 0)
+        {
+            MSqlQuery duplicateQuery(MSqlQuery::InitCon());
+            duplicateQuery.prepare("SELECT person "
+                                   "  FROM people "
+                                   " WHERE name = REPLACE( "
+                                   "               (SELECT name FROM people "
+                                   "                 WHERE person = :ID), "
+                                   "               '\\0', '');");
+            // Rather than build an updateQuery with the table name inserted in
+            // the QString used to build the SQL and reusing it for credits and
+            // recordedcredits, use 2 prepared queries since we'll be executing
+            // the updates thousands (or tens of thousands) of times each
+            MSqlQuery updateCreditsQuery(MSqlQuery::InitCon());
+            updateCreditsQuery.prepare("UPDATE credits "
+                                       "   SET person = :ID "
+                                       " WHERE person = :DUPLICATEID;");
+            MSqlQuery updateRecordedCreditsQuery(MSqlQuery::InitCon());
+            updateRecordedCreditsQuery.prepare("UPDATE recordedcredits "
+                                               "   SET person = :ID "
+                                               " WHERE person = :DUPLICATEID;");
+            MSqlQuery deleteQuery(MSqlQuery::InitCon());
+            deleteQuery.prepare("DELETE FROM people "
+                                " WHERE person = :ID;");
+            MSqlQuery updatePeopleQuery(MSqlQuery::InitCon());
+            updatePeopleQuery.prepare("UPDATE people "
+                                      "   SET name = REPLACE(name, '\\0', '') "
+                                      " WHERE person = :ID;");
+            VERBOSE(VB_IMPORTANT, "Fixing corrupt data in the people table. "
+                                  "This may take a while. Please do not stop "
+                                  "the program until it has finished.");
+            while (peopleQuery.next())
+            {
+                int person = peopleQuery.value(0).toInt();
+                duplicateQuery.bindValue(":ID", person);
+                if (duplicateQuery.exec() && duplicateQuery.isActive() &&
+                    duplicateQuery.size() > 0)
+                {
+                    // Duplicate record, replace references and remove dup
+                    while (duplicateQuery.next())
+                    {
+                        int duplicatePerson = duplicateQuery.value(0).toInt();
+                        bool success = true;
+                        updateCreditsQuery.bindValue(":ID", person);
+                        updateCreditsQuery.bindValue(":DUPLICATEID",
+                                                     duplicatePerson);
+                        if (!updateCreditsQuery.exec())
+                        {
+                            success = false;
+                            MythDB::DBError(QString("Updating references to "
+                                                    "duplicate person record "
+                                                    "in credits: %1 -> %2")
+                                                    .arg(duplicatePerson)
+                                                    .arg(person),
+                                            updateCreditsQuery);
+                        }
+                        updateRecordedCreditsQuery.bindValue(":ID", person);
+                        updateRecordedCreditsQuery.bindValue(":DUPLICATEID",
+                                                             duplicatePerson);
+                        if (!updateRecordedCreditsQuery.exec())
+                        {
+                            success = false;
+                            MythDB::DBError(QString("Updating references to "
+                                                    "duplicate person record "
+                                                    "in recordedcredits: "
+                                                    "%1 -> %2")
+                                                    .arg(duplicatePerson)
+                                                    .arg(person),
+                                            updateRecordedCreditsQuery);
+                        }
+                        if (success)
+                        {
+                            // We need to keep the original person and fix the
+                            // corrupt name since we may have more than one
+                            // duplicate in the wild (with varying numbers
+                            // of null-pad characters) if users have edited
+                            // the database directly
+                            deleteQuery.bindValue(":ID", duplicatePerson);
+                            if (!deleteQuery.exec())
+                            {
+                                MythDB::DBError(
+                                    QString("Deleting duplicate person "
+                                            "record: %1").arg(duplicatePerson),
+                                            deleteQuery);
+                            }
+                            // This cannot be done outside the duplicate-check
+                            // conditional, even though it's done in the if and
+                            // the else because it's only safe to do if success
+                            updatePeopleQuery.bindValue(":ID", person);
+                            if (!updatePeopleQuery.exec())
+                            {
+                                MythDB::DBError(
+                                    QString("Fixing corrupt people.name "
+                                            "for person: %1)").arg(person),
+                                    updatePeopleQuery);
+                            }
+                        }
+                    }
+                }
+                else
+                {
+                    // Not duplicated, corrupt record, fix name
+                    updatePeopleQuery.bindValue(":ID", person);
+                    if (!updatePeopleQuery.exec())
+                    {
+                        MythDB::DBError(QString("Fixing corrupt people.name "
+                                                "for person: %1)").arg(person),
+                                                updatePeopleQuery);
+                    }
+                }
+            }
+            VERBOSE(VB_IMPORTANT, "Finished fixing corrupt data in the people "
+                                  "table.");
+        }
+
+        const char *updates[] = {
+"UPDATE programgenres SET genre = REPLACE(genre, '\\0', '');",
+"UPDATE programrating SET system = REPLACE(system, '\\0', ''), "
+"                         rating = REPLACE(rating, '\\0', '');",
+"UPDATE recordedrating SET system = REPLACE(system, '\\0', ''), "
+"                          rating = REPLACE(rating, '\\0', '');",
+NULL
+};
+        if (!performActualUpdate(updates, "1225", dbver))
+            return false;
+    }
+
     return true;
 }