Add configuration to use the legacy query for old synapse to get room names.

src/main/java/io/kamax/mxisd/backend/sql/synapse/Synapse.java

@@ -29,15 +29,19 @@ import java.util.Optional;
 
 public class Synapse {
 
-    private SqlConnectionPool pool;
+    private final SqlConnectionPool pool;
+    private final SynapseSqlProviderConfig providerConfig;
 
     public Synapse(SynapseSqlProviderConfig sqlCfg) {
         this.pool = new SqlConnectionPool(sqlCfg);
+        providerConfig = sqlCfg;
     }
 
     public Optional<String> getRoomName(String id) {
+        String query = providerConfig.isLegacyRoomNames() ? SynapseQueries.getLegacyRoomName() : SynapseQueries.getRoomName();
+
         return pool.withConnFunction(conn -> {
-            PreparedStatement stmt = conn.prepareStatement(SynapseQueries.getRoomName());
+            try (PreparedStatement stmt = conn.prepareStatement(query)) {
                 stmt.setString(1, id);
                 ResultSet rSet = stmt.executeQuery();
                 if (!rSet.next()) {
@@ -45,7 +49,7 @@ public class Synapse {
                 }
 
                 return Optional.ofNullable(rSet.getString(1));
+            }
         });
     }
-
 }

src/main/java/io/kamax/mxisd/backend/sql/synapse/SynapseQueries.java

@@ -75,4 +75,7 @@ public class SynapseQueries {
         return "select name from room_stats_state where room_id = ? limit 1";
     }
 
+    public static String getLegacyRoomName() {
+        return "select r.name from room_names r, events e, (select r1.room_id,max(e1.origin_server_ts) ts from room_names r1, events e1 where r1.event_id = e1.event_id group by r1.room_id) rle where e.origin_server_ts = rle.ts and r.event_id = e.event_id and r.room_id = ?";
+    }
 }

src/main/java/io/kamax/mxisd/config/sql/synapse/SynapseSqlProviderConfig.java

@@ -24,9 +24,23 @@ import io.kamax.mxisd.UserIdType;
 import io.kamax.mxisd.backend.sql.synapse.SynapseQueries;
 import io.kamax.mxisd.config.sql.SqlConfig;
 import org.apache.commons.lang.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class SynapseSqlProviderConfig extends SqlConfig {
 
+    private transient final Logger log = LoggerFactory.getLogger(SynapseSqlProviderConfig.class);
+
+    private boolean legacyRoomNames = false;
+
+    public boolean isLegacyRoomNames() {
+        return legacyRoomNames;
+    }
+
+    public void setLegacyRoomNames(boolean legacyRoomNames) {
+        this.legacyRoomNames = legacyRoomNames;
+    }
+
     @Override
     protected String getProviderName() {
         return "Synapse SQL";
@@ -65,4 +79,12 @@ public class SynapseSqlProviderConfig extends SqlConfig {
         printConfig();
     }
 
+    @Override
+    protected void printConfig() {
+        super.printConfig();
+
+        if (isEnabled()) {
+            log.info("Use legacy room name query: {}", isLegacyRoomNames());
+        }
+    }
 }