diff --git a/repository-ydb-v1/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java b/repository-ydb-v1/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java
index 7382cde3..f1ecc5fd 100644
--- a/repository-ydb-v1/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java
+++ b/repository-ydb-v1/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java
@@ -5,6 +5,7 @@
 import com.yandex.ydb.ValueProtos;
 import com.yandex.ydb.core.Result;
 import com.yandex.ydb.core.Status;
+import com.yandex.ydb.core.StatusCode;
 import com.yandex.ydb.table.Session;
 import com.yandex.ydb.table.query.DataQueryResult;
 import com.yandex.ydb.table.query.Params;
@@ -36,12 +37,15 @@
 import tech.ydb.yoj.repository.db.cache.TransactionLocal;
 import tech.ydb.yoj.repository.db.exception.IllegalTransactionIsolationLevelException;
 import tech.ydb.yoj.repository.db.exception.IllegalTransactionScanException;
+import tech.ydb.yoj.repository.db.exception.OptimisticLockException;
 import tech.ydb.yoj.repository.db.exception.RepositoryException;
 import tech.ydb.yoj.repository.db.exception.UnavailableException;
 import tech.ydb.yoj.repository.db.readtable.ReadTableParams;
 import tech.ydb.yoj.repository.ydb.bulk.BulkMapper;
 import tech.ydb.yoj.repository.ydb.client.ResultSetConverter;
 import tech.ydb.yoj.repository.ydb.client.YdbConverter;
+import tech.ydb.yoj.repository.ydb.client.YdbValidator;
+import tech.ydb.yoj.repository.ydb.exception.BadSessionException;
 import tech.ydb.yoj.repository.ydb.exception.ResultTruncatedException;
 import tech.ydb.yoj.repository.ydb.exception.UnexpectedException;
 import tech.ydb.yoj.repository.ydb.exception.YdbComponentUnavailableException;
@@ -65,9 +69,6 @@
 import static com.google.common.base.Strings.emptyToNull;
 import static java.lang.String.format;
 import static java.util.stream.Collectors.toList;
-import static tech.ydb.yoj.repository.ydb.client.YdbValidator.validate;
-import static tech.ydb.yoj.repository.ydb.client.YdbValidator.validatePkConstraint;
-import static tech.ydb.yoj.repository.ydb.client.YdbValidator.validateTruncatedResults;
 
 public class YdbRepositoryTransaction<REPO extends YdbRepository>
         implements BaseDb, RepositoryTransaction, YdbTable.QueryExecutor, TransactionLocal.Holder {
@@ -89,6 +90,7 @@ public class YdbRepositoryTransaction<REPO extends YdbRepository>
     protected String txId = null;
     private String firstNonNullTxId = null; // used for logs
     private String closeAction = null; // used to detect of usage transaction after commit()/rollback()
+    private boolean isBadSession = false;
 
     public YdbRepositoryTransaction(REPO repo, @NonNull TxOptions options) {
         this.repo = repo;
@@ -136,8 +138,8 @@ public void rollback() {
     private void doCommit() {
         try {
             Status status = YdbOperations.safeJoin(session.commitTransaction(txId, new CommitTxSettings()));
-            validatePkConstraint(status.getIssues());
             validate("commit", status.getCode(), status.toString());
+            YdbValidator.validatePkConstraint(status.getIssues());
         } catch (YdbComponentUnavailableException | YdbOverloadedException e) {
             throw new UnavailableException("Unknown transaction state: commit was sent, but result is unknown", e);
         }
@@ -162,8 +164,18 @@ private void closeStreams() {
         }
     }
 
+    private void validate(String request, StatusCode statusCode, String response) {
+        try {
+            YdbValidator.validate(request, statusCode, response);
+        } catch (BadSessionException | OptimisticLockException e) {
+            transactionLocal.log().info("Request got %s: DB tx was invalidated", e.getClass().getSimpleName());
+            isBadSession = true;
+            throw e;
+        }
+    }
+
     private boolean isFinalActionNeeded(String actionName) {
-        if (session == null) {
+        if (session == null || isBadSession) {
             transactionLocal.log().info("No-op %s: no active DB session", actionName);
             return false;
         }
@@ -285,6 +297,7 @@ private <PARAMS, RESULT> List<RESULT> doExecuteDataQuery(Statement<PARAMS, RESUL
         // settings.setTraceId();
 
         Result<DataQueryResult> result = YdbOperations.safeJoin(session.executeDataQuery(yql, txControl, sdkParams, settings));
+        validate(yql, result.getCode(), result.toString());
 
         result.ok().ifPresent(queryResult -> {
             txId = emptyToNull(queryResult.getTxId());
@@ -293,8 +306,7 @@ private <PARAMS, RESULT> List<RESULT> doExecuteDataQuery(Statement<PARAMS, RESUL
             }
         });
 
-        validatePkConstraint(result.getIssues());
-        validate(yql, result.getCode(), result.toString());
+        YdbValidator.validatePkConstraint(result.getIssues());
 
         DataQueryResult queryResult = result.expect("expect result after sql execution");
         if (queryResult.getResultSetCount() > 1) {
@@ -303,7 +315,7 @@ private <PARAMS, RESULT> List<RESULT> doExecuteDataQuery(Statement<PARAMS, RESUL
         if (queryResult.getResultSetCount() == 0) {
             return null;
         }
-        validateTruncatedResults(yql, queryResult);
+        YdbValidator.validateTruncatedResults(yql, queryResult);
 
         ResultSetReader resultSet = queryResult.getResultSet(0);
         return new ResultSetConverter(resultSet).stream(statement::readResult).collect(toList());
@@ -430,7 +442,7 @@ public <IN> void bulkUpsert(BulkMapper<IN> mapper, List<IN> input, BulkParams pa
             } catch (RepositoryException e) {
                 throw e;
             } catch (Exception e) {
-                throw new UnexpectedException("Could not bulk insert into table " + tableName);
+                throw new UnexpectedException("Could not bulk insert into table " + tableName, e);
             }
         });
     }
@@ -489,7 +501,7 @@ public <PARAMS, RESULT> Stream<RESULT> readTable(ReadTableMapper<PARAMS, RESULT>
         } catch (RepositoryException e) {
             throw e;
         } catch (Exception e) {
-            throw new UnexpectedException("Could not read table " + tableName);
+            throw new UnexpectedException("Could not read table " + tableName, e);
         }
     }
 
diff --git a/repository-ydb-v2/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java b/repository-ydb-v2/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java
index 08279485..4807b6fa 100644
--- a/repository-ydb-v2/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java
+++ b/repository-ydb-v2/src/main/java/tech/ydb/yoj/repository/ydb/YdbRepositoryTransaction.java
@@ -10,6 +10,7 @@
 import org.slf4j.LoggerFactory;
 import tech.ydb.core.Result;
 import tech.ydb.core.Status;
+import tech.ydb.core.StatusCode;
 import tech.ydb.proto.ValueProtos;
 import tech.ydb.table.Session;
 import tech.ydb.table.query.DataQueryResult;
@@ -37,12 +38,15 @@
 import tech.ydb.yoj.repository.db.cache.TransactionLocal;
 import tech.ydb.yoj.repository.db.exception.IllegalTransactionIsolationLevelException;
 import tech.ydb.yoj.repository.db.exception.IllegalTransactionScanException;
+import tech.ydb.yoj.repository.db.exception.OptimisticLockException;
 import tech.ydb.yoj.repository.db.exception.RepositoryException;
 import tech.ydb.yoj.repository.db.exception.UnavailableException;
 import tech.ydb.yoj.repository.db.readtable.ReadTableParams;
 import tech.ydb.yoj.repository.ydb.bulk.BulkMapper;
 import tech.ydb.yoj.repository.ydb.client.ResultSetConverter;
 import tech.ydb.yoj.repository.ydb.client.YdbConverter;
+import tech.ydb.yoj.repository.ydb.client.YdbValidator;
+import tech.ydb.yoj.repository.ydb.exception.BadSessionException;
 import tech.ydb.yoj.repository.ydb.exception.ResultTruncatedException;
 import tech.ydb.yoj.repository.ydb.exception.UnexpectedException;
 import tech.ydb.yoj.repository.ydb.exception.YdbComponentUnavailableException;
@@ -66,9 +70,6 @@
 import static com.google.common.base.Strings.emptyToNull;
 import static java.lang.String.format;
 import static java.util.stream.Collectors.toList;
-import static tech.ydb.yoj.repository.ydb.client.YdbValidator.validate;
-import static tech.ydb.yoj.repository.ydb.client.YdbValidator.validatePkConstraint;
-import static tech.ydb.yoj.repository.ydb.client.YdbValidator.validateTruncatedResults;
 
 public class YdbRepositoryTransaction<REPO extends YdbRepository>
         implements BaseDb, RepositoryTransaction, YdbTable.QueryExecutor, TransactionLocal.Holder {
@@ -90,6 +91,7 @@ public class YdbRepositoryTransaction<REPO extends YdbRepository>
     protected String txId = null;
     private String firstNonNullTxId = null; // used for logs
     private String closeAction = null; // used to detect of usage transaction after commit()/rollback()
+    private boolean isBadSession = false;
 
     public YdbRepositoryTransaction(REPO repo, @NonNull TxOptions options) {
         this.repo = repo;
@@ -137,8 +139,8 @@ public void rollback() {
     private void doCommit() {
         try {
             Status status = YdbOperations.safeJoin(session.commitTransaction(txId, new CommitTxSettings()));
-            validatePkConstraint(status.getIssues());
             validate("commit", status.getCode(), status.toString());
+            YdbValidator.validatePkConstraint(status.getIssues());
         } catch (YdbComponentUnavailableException | YdbOverloadedException e) {
             throw new UnavailableException("Unknown transaction state: commit was sent, but result is unknown", e);
         }
@@ -163,8 +165,18 @@ private void closeStreams() {
         }
     }
 
+    private void validate(String request, StatusCode statusCode, String response) {
+        try {
+            YdbValidator.validate(request, statusCode, response);
+        } catch (BadSessionException | OptimisticLockException e) {
+            transactionLocal.log().info("Request got %s: DB tx was invalidated", e.getClass().getSimpleName());
+            isBadSession = true;
+            throw e;
+        }
+    }
+
     private boolean isFinalActionNeeded(String actionName) {
-        if (session == null) {
+        if (session == null || isBadSession) {
             transactionLocal.log().info("No-op %s: no active DB session", actionName);
             return false;
         }
@@ -285,6 +297,7 @@ private <PARAMS, RESULT> List<RESULT> doExecuteDataQuery(Statement<PARAMS, RESUL
         // settings.setTraceId();
 
         Result<DataQueryResult> result = YdbOperations.safeJoin(session.executeDataQuery(yql, txControl, sdkParams, settings));
+        validate(yql, result.getStatus().getCode(), result.toString());
 
         if (result.isSuccess()) {
             txId = emptyToNull(result.getValue().getTxId());
@@ -293,8 +306,7 @@ private <PARAMS, RESULT> List<RESULT> doExecuteDataQuery(Statement<PARAMS, RESUL
             }
         }
 
-        validatePkConstraint(result.getStatus().getIssues());
-        validate(yql, result.getStatus().getCode(), result.toString());
+        YdbValidator.validatePkConstraint(result.getStatus().getIssues());
 
         DataQueryResult queryResult = result.getValue();
         if (queryResult.getResultSetCount() > 1) {
@@ -303,7 +315,7 @@ private <PARAMS, RESULT> List<RESULT> doExecuteDataQuery(Statement<PARAMS, RESUL
         if (queryResult.getResultSetCount() == 0) {
             return null;
         }
-        validateTruncatedResults(yql, queryResult);
+        YdbValidator.validateTruncatedResults(yql, queryResult);
 
         ResultSetReader resultSet = queryResult.getResultSet(0);
         return new ResultSetConverter(resultSet).stream(statement::readResult).collect(toList());
@@ -429,7 +441,7 @@ public <IN> void bulkUpsert(BulkMapper<IN> mapper, List<IN> input, BulkParams pa
             } catch (RepositoryException e) {
                 throw e;
             } catch (Exception e) {
-                throw new UnexpectedException("Could not bulk insert into table " + tableName);
+                throw new UnexpectedException("Could not bulk insert into table " + tableName, e);
             }
         });
     }
@@ -488,7 +500,7 @@ public <PARAMS, RESULT> Stream<RESULT> readTable(ReadTableMapper<PARAMS, RESULT>
         } catch (RepositoryException e) {
             throw e;
         } catch (Exception e) {
-            throw new UnexpectedException("Could not read table " + tableName);
+            throw new UnexpectedException("Could not read table " + tableName, e);
         }
     }
 
diff --git a/repository/src/main/java/tech/ydb/yoj/repository/db/cache/TransactionLocal.java b/repository/src/main/java/tech/ydb/yoj/repository/db/cache/TransactionLocal.java
index 15184786..7be6daa1 100644
--- a/repository/src/main/java/tech/ydb/yoj/repository/db/cache/TransactionLocal.java
+++ b/repository/src/main/java/tech/ydb/yoj/repository/db/cache/TransactionLocal.java
@@ -11,9 +11,8 @@
 import java.util.Map;
 import java.util.function.Supplier;
 
-@SuppressWarnings({"rawtypes", "unchecked"})
 public class TransactionLocal {
-    private final Map<Supplier, Object> singletons = new IdentityHashMap<>();
+    private final Map<Supplier<?>, Object> singletons = new IdentityHashMap<>();
 
     private final Supplier<FirstLevelCache> firstLevelCacheSupplier;
     private final Supplier<ProjectionCache> projectionCacheSupplier;
@@ -29,6 +28,7 @@ public static TransactionLocal get() {
         return BaseDb.current(Holder.class).getTransactionLocal();
     }
 
+    @SuppressWarnings("unchecked")
     public <X> X instance(@NonNull Supplier<X> supplier) {
         return (X) singletons.computeIfAbsent(supplier, Supplier::get);
     }