reuse pdb writers

pdb-plotting/src/main/java/org/lucares/recommind/logs/TcpIngestor.java

@@ -158,11 +158,15 @@ public class TcpIngestor implements AutoCloseable {
 
 		serverThreadPool.submit(() -> {
 			Thread.currentThread().setName("db-ingestion");
-			try {
-				db.put(new BlockingQueueIterator<>(queue, Entry.POISON));
-			} catch (final Exception e) {
-				e.printStackTrace();
-				throw e;
+
+			boolean finished = false;
+			while (!finished) {
+				try {
+					db.put(new BlockingQueueIterator<>(queue, Entry.POISON));
+					finished = true;
+				} catch (final Exception e) {
+					e.printStackTrace();
+				}
 			}
 			return null;
 		});
@@ -188,6 +192,8 @@ public class TcpIngestor implements AutoCloseable {
 				} catch (final SocketTimeoutException e) {
 					// expected every 100ms
 					// needed to be able to stop the server
+				} catch (final Exception e) {
+					e.printStackTrace();
 				}
 			}
 			System.out.println("not accepting new connections. ");