+
+bool AbstractSqlStorage::upgradeDb()
+{
+ if (schemaVersion() <= installedSchemaVersion())
+ return true;
+
+ QSqlDatabase db = logDb();
+
+ // TODO: For databases that support it (e.g. almost only PostgreSQL), wrap upgrades in a
+ // transaction. This will need careful testing of potential additional space requirements and
+ // any database modifications that might not be allowed in a transaction.
+
+ for (int ver = installedSchemaVersion() + 1; ver <= schemaVersion(); ver++) {
+ foreach(QString queryString, upgradeQueries(ver)) {
+ QSqlQuery query = db.exec(queryString);
+ if (!watchQuery(query)) {
+ // Individual upgrade query failed, bail out
+ qCritical() << "Unable to upgrade Logging Backend! Upgrade query in schema version"
+ << ver << "failed.";
+ return false;
+ }
+ }
+
+ // Update the schema version for each intermediate step. This ensures that any interrupted
+ // upgrades have a greater chance of resuming correctly after core restart.
+ //
+ // Almost all databases make single queries atomic (fully works or fully fails, no partial),
+ // and with many of the longest migrations being a single query, this makes upgrade
+ // interruptions much more likely to leave the database in a valid intermediate schema
+ // version.
+ if (!updateSchemaVersion(ver)) {
+ // Updating the schema version failed, bail out
+ qCritical() << "Unable to upgrade Logging Backend! Setting schema version"
+ << ver << "failed.";
+ return false;
+ }
+ }
+
+ // Update the schema version for the final step. Split this out to offer more informative
+ // logging (though setting schema version really should not fail).
+ if (!updateSchemaVersion(schemaVersion())) {
+ // Updating the final schema version failed, bail out
+ qCritical() << "Unable to upgrade Logging Backend! Setting final schema version"
+ << schemaVersion() << "failed.";
+ return false;
+ }
+
+ // If we made it here, everything seems to have worked!
+ return true;
+}
+
+
+int AbstractSqlStorage::schemaVersion()
+{
+ // returns the newest Schema Version!
+ // not the currently used one! (though it can be the same)
+ if (_schemaVersion > 0)
+ return _schemaVersion;
+
+ int version;
+ bool ok;
+ // Schema versions are stored in the 'version/##' subfolders.
+ QDir dir = QDir(QString(":/SQL/%1/version/").arg(displayName()));
+ foreach(QFileInfo fileInfo, dir.entryInfoList()) {
+ if (!fileInfo.isDir())
+ continue;
+
+ version = fileInfo.fileName().toInt(&ok);
+ if (!ok)
+ continue;
+
+ if (version > _schemaVersion)
+ _schemaVersion = version;
+ }
+ return _schemaVersion;