Added returning of database version to metadata

jdbc/src/main/java/tech/ydb/jdbc/context/YdbContext.java

@@ -1,5 +1,6 @@
 package tech.ydb.jdbc.context;
 
+import java.nio.charset.StandardCharsets;
 import java.sql.SQLDataException;
 import java.sql.SQLException;
 import java.time.Duration;
@@ -10,10 +11,13 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+import com.google.common.base.Supplier;
+import com.google.common.base.Suppliers;
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 
@@ -50,12 +54,15 @@
 import tech.ydb.table.description.TableDescription;
 import tech.ydb.table.impl.PooledTableClient;
 import tech.ydb.table.query.DataQuery;
+import tech.ydb.table.query.DataQueryResult;
 import tech.ydb.table.query.ExplainDataQueryResult;
+import tech.ydb.table.result.ResultSetReader;
 import tech.ydb.table.rpc.grpc.GrpcTableRpc;
 import tech.ydb.table.settings.DescribeTableSettings;
 import tech.ydb.table.settings.ExplainDataQuerySettings;
 import tech.ydb.table.settings.PrepareDataQuerySettings;
 import tech.ydb.table.settings.RequestSettings;
+import tech.ydb.table.transaction.TxControl;
 import tech.ydb.table.values.Type;
 
 /**
@@ -87,6 +94,7 @@ public class YdbContext implements AutoCloseable {
     private final Cache<String, QueryStat> statsCache;
     private final Cache<String, Map<String, Type>> queryParamsCache;
     private final Cache<String, TableDescription> tableDescribeCache;
+    private final Supplier<String> version = Suppliers.memoizeWithExpiration(this::readVersion, 1, TimeUnit.HOURS);
 
     private final boolean autoResizeSessionPool;
     private final AtomicInteger connectionsCount = new AtomicInteger();
@@ -144,15 +152,14 @@ public YdbTypes getTypes() {
         return types;
     }
 
-    /**
-     * Grpc Transport for other API YDB server clients
-     *
-     * @return grpcTransport for YDB
-     */
     public GrpcTransport getGrpcTransport() {
         return grpcTransport;
     }
 
+    public String getDatabaseVersion() {
+        return version.get();
+    }
+
     public YdbTracer getTracer() {
         return config.isTxTracedEnabled() ? YdbTracer.current() : YdbTracerNone.DISABLED;
     }
@@ -338,6 +345,21 @@ public static YdbContext createContext(YdbConfig config) throws SQLException {
         }
     }
 
+    private String readVersion() {
+        Result<DataQueryResult> res = retryCtx.supplyResult(
+                s -> s.executeDataQuery("SELECT version();", TxControl.snapshotRo())
+        ).join();
+
+        if (res.isSuccess()) {
+            ResultSetReader rs = res.getValue().getResultSet(0);
+            if (rs.next()) {
+                return rs.getColumn(0).getBytesAsString(StandardCharsets.UTF_8);
+            }
+        }
+        return "unknown";
+    }
+
+
     public <T extends RequestSettings<?>> T withDefaultTimeout(T settings) {
         Duration operation = operationOptions.getDeadlineTimeout();
         if (!operation.isZero() && !operation.isNegative()) {

jdbc/src/main/java/tech/ydb/jdbc/impl/YdbDatabaseMetaDataImpl.java

@@ -114,7 +114,17 @@ public String getDatabaseProductName() {
 
     @Override
     public String getDatabaseProductVersion() {
-        return "unspecified"; // TODO: don't know how to get YDB version
+        return connection.getCtx().getDatabaseVersion();
+    }
+
+    @Override
+    public int getDatabaseMajorVersion() {
+        return 0; // unknown
+    }
+
+    @Override
+    public int getDatabaseMinorVersion() {
+        return 0; // unknown
     }
 
     @Override
@@ -1233,16 +1243,6 @@ public int getResultSetHoldability() throws SQLException {
         return connection.getHoldability();
     }
 
-    @Override
-    public int getDatabaseMajorVersion() {
-        return 0; // unknown
-    }
-
-    @Override
-    public int getDatabaseMinorVersion() {
-        return 0; // unknown
-    }
-
     @Override
     public int getJDBCMajorVersion() {
         return YdbDriverInfo.JDBC_MAJOR_VERSION;

jdbc/src/test/java/tech/ydb/jdbc/impl/YdbDatabaseMetaDataImplTest.java

@@ -126,7 +126,7 @@ public void metaDataValuesTest() throws SQLException {
         Assertions.assertFalse(metaData.nullsAreSortedAtStart());
         Assertions.assertFalse(metaData.nullsAreSortedAtEnd());
         Assertions.assertEquals("YDB", metaData.getDatabaseProductName());
-        Assertions.assertEquals("unspecified", metaData.getDatabaseProductVersion());
+        Assertions.assertFalse(metaData.getDatabaseProductVersion().isEmpty());
 
         Assertions.assertEquals(YdbDriverInfo.DRIVER_NAME, metaData.getDriverName());
         Assertions.assertEquals(YdbDriverInfo.DRIVER_VERSION, metaData.getDriverVersion());