inner-730: fixed: 'use schema' cause slowQuery thread terminated. (#2397)

Signed-off-by: dcy <dcy10000@gmail.com>
(cherry picked from commit 84c3f87391)

src/main/java/com/actiontech/dble/log/slow/SlowQueryLogProcessor.java

@@ -7,7 +7,6 @@ package com.actiontech.dble.log.slow;
 
 import com.actiontech.dble.config.model.SystemConfig;
 import com.actiontech.dble.log.DailyRotateLogStore;
-
 import com.actiontech.dble.server.status.SlowQueryLog;
 import com.actiontech.dble.server.trace.TraceResult;
 import com.actiontech.dble.services.mysqlsharding.ShardingService;
@@ -16,7 +15,6 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.concurrent.*;
 
@@ -52,8 +50,11 @@ public class SlowQueryLogProcessor extends Thread {
                 if (log == null) {
                     continue;
                 }
-                writeLog(log);
-                logSize++;
+
+                if (writeLog(log)) {
+                    logSize++;
+                }
+
                 synchronized (this) {
                     if ((logSize - lastLogSize) % SlowQueryLog.getInstance().getFlushSize() == 0) {
                         flushLog();
@@ -62,29 +63,34 @@ public class SlowQueryLogProcessor extends Thread {
             }
             // disable slow_query_log, end task
             while ((log = queue.poll()) != null) {
-                writeLog(log);
-                logSize++;
+                if (writeLog(log)) {
+                    logSize++;
+                }
             }
-            scheduler.shutdown();
-            flushLog();
-            store.close();
         } catch (IOException e) {
             LOGGER.info("transaction log error:", e);
             store.close();
+        } finally {
+            scheduler.shutdown();
+            flushLog();
+            store.close();
         }
     }
 
-    private synchronized void writeLog(SlowQueryLogEntry log) throws IOException {
-        if (log == null)
-            return;
+    private synchronized boolean writeLog(SlowQueryLogEntry log) throws IOException {
+        if (log == null) {
+            return false;
+        }
         byte[] data;
         try {
             data = log.toString().getBytes("utf-8");
-        } catch (UnsupportedEncodingException e) {
-            return;
+        } catch (Exception e) {
+            LOGGER.warn("generate write log error ", e);
+            return false;
         }
         ByteBuffer buffer = ByteBuffer.wrap(data);
         store.write(buffer);
+        return true;
     }
 
     private void flushLog() {

src/main/java/com/actiontech/dble/server/response/ShowTables.java

@@ -27,6 +27,7 @@ import com.actiontech.dble.plan.visitor.MySQLItemVisitor;
 import com.actiontech.dble.route.RouteResultset;
 import com.actiontech.dble.route.util.RouterUtil;
 import com.actiontech.dble.server.parser.ServerParse;
+import com.actiontech.dble.server.trace.TraceResult;
 import com.actiontech.dble.services.mysqlsharding.ShardingService;
 import com.actiontech.dble.singleton.ProxyMeta;
 import com.actiontech.dble.util.StringUtil;
@@ -110,6 +111,7 @@ public final class ShowTables {
         }
         RouterUtil.routeToSingleNode(rrs, node);
         ShowTablesHandler showTablesHandler = new ShowTablesHandler(rrs, shardingService.getSession2(), info);
+        shardingService.getSession2().setPreExecuteEnd(TraceResult.SqlTraceType.SINGLE_NODE_QUERY);
         showTablesHandler.execute();
     }