Add max query timeout setting for h2 dialect

Change-Id: I78985722fc01f72885318d128a05d617087d8eea

Documentation/config-gerrit.txt

@@ -1905,6 +1905,13 @@ utils (e.g. MigrateToNoteDb).
 +
 Default is `false`.
 
+[[database.h2.maxQueryTimeout]]database.h2.maxQueryTimeout::
++
+The maximum timeout of a query in milliseconds.
+(see http://www.h2database.com/javadoc/org/h2/engine/DbSettings.html?#MAX_QUERY_TIMEOUT[MAX_QUERY_TIMEOUT]).
++
+The default is 0, meaning no limit.
+
 [[download]]
 === Section download
 

java/com/google/gerrit/server/schema/H2.java

@@ -47,6 +47,7 @@ class H2 extends BaseDataSourceType {
 
   public static String appendUrlOptions(Config cfg, String url) {
     long h2CacheSize = cfg.getLong("database", "h2", "cacheSize", -1);
+    long h2MaxQueryTimeout = cfg.getLong("database", "h2", "maxQueryTimeout", -1);
     boolean h2AutoServer = cfg.getBoolean("database", "h2", "autoServer", false);
 
     StringBuilder urlBuilder = new StringBuilder().append(url);
@@ -55,6 +56,9 @@ class H2 extends BaseDataSourceType {
       // H2 CACHE_SIZE is always given in KB
       urlBuilder.append(";CACHE_SIZE=").append(h2CacheSize / 1024);
     }
+    if (h2MaxQueryTimeout >= 0) {
+      urlBuilder.append(";MAX_QUERY_TIMEOUT=").append(h2MaxQueryTimeout);
+    }
     if (h2AutoServer) {
       urlBuilder.append(";AUTO_SERVER=TRUE");
     }