Bug #25702850 TOO LARGE RESULT SIZE REPORTED FROM TUP-BLOCK TO LQH

The pseudo_read instruction FLUSH_AI attrInfo is used to
produce two TRANSID_AI result rows from the same row: One
going to the SPJ block with keys for fuether lookups, and the
other to the API containing the result row. The total length
of both of these rows were reported in the TUPKEYCONF signal
from TUP -> LQH. This could cause LQH to prematurely terminate
scan batches as it believed that the total number of
ScanBatch 'bytes' was about to be exhausted.

This patch change this such that only the result row going to the
API is reported as part of the 'read_length' being reported.

Author: Ole John Aske

mysql-test/suite/ndb/r/ndbinfo.result

@@ -1198,7 +1198,7 @@ tot_key_bytes_returned	4220
 tot_frag_scans	56
 tot_scan_rows_examined	306
 tot_scan_rows_returned	215
-tot_scan_bytes_returned	7116
+tot_scan_bytes_returned	5564
 tot_scan_prog_bytes	288
 tot_scan_bound_bytes	0
 tot_scan_inst_exec	305
@@ -1359,7 +1359,7 @@ new.log_tot_key_attrinfo_bytes - old.log_tot_key_attrinfo_bytes	2
 new.tot_key_keyinfo_bytes - old.tot_key_keyinfo_bytes	20
 new.tot_key_prog_bytes - old.tot_key_prog_bytes	168
 new.tot_key_inst_exec - old.tot_key_inst_exec	7
-new.tot_key_bytes_returned - old.tot_key_bytes_returned	88
+new.tot_key_bytes_returned - old.tot_key_bytes_returned	56
 new.tot_frag_scans - old.tot_frag_scans	0
 new.tot_scan_rows_examined - old.tot_scan_rows_examined	0
 new.tot_scan_rows_returned - old.tot_scan_rows_returned	0

storage/ndb/src/kernel/blocks/dbtup/DbtupBuffer.cpp

@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -206,6 +206,23 @@ void Dbtup::sendReadAttrinfo(Signal* signal,
               */
              (nodeId == getOwnNodeId() && connectedToNode));
 
+  /**
+   * If a previous read_pseudo executed a 'FLUSH_AI', we may
+   * already have sent a TRANSID_AI signal with the result row
+   * to the API node. The result size was then already recorded
+   * in 'read_length' and we should not add the size of this 
+   * row as it is not part of the 'result' . 
+   */
+  if (req_struct->read_length != 0)
+  {
+    ndbassert(!is_api);  // API result already FLUSH_AI'ed
+  }
+  else
+  {
+    // No API-result produced yet, record this
+    req_struct->read_length = ToutBufIndex;
+  }
+
   if (connectedToNode){
     /**
      * Own node -> execute direct

storage/ndb/src/kernel/blocks/dbtup/DbtupExecQuery.cpp

@@ -1287,8 +1287,7 @@ int Dbtup::handleReadReq(Signal* signal,
 // We have read all data into coutBuffer. Now send it to the API.
 /* ------------------------------------------------------------------------- */
       jam();
-      Uint32 TnoOfDataRead= (Uint32) ret;
-      req_struct->read_length += TnoOfDataRead;
+      const Uint32 TnoOfDataRead= (Uint32) ret;
       sendReadAttrinfo(signal, req_struct, TnoOfDataRead);
       return 0;
     }
@@ -2861,7 +2860,6 @@ int Dbtup::interpreterStartLab(Signal* signal,
      *    This is used for ANYVALUE and interpreted delete.
      */
     req_struct->log_size+= RlogSize;
-    req_struct->read_length += RattroutCounter;
     sendReadAttrinfo(signal, req_struct, RattroutCounter);
     if (RlogSize > 0) {
       return sendLogAttrinfo(signal, req_struct, RlogSize, regOperPtr);

storage/ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp

@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -2987,7 +2987,23 @@ Dbtup::flush_read_buffer(KeyReqStruct *req_struct,
 
   req_struct->out_buf_index = 0; // Reset buffer
   req_struct->out_buf_bits = 0;
-  req_struct->read_length += len;
+
+  const Uint32 type = getNodeInfo(destNode).m_type;
+  const bool is_api = (type >= NodeInfo::API && type <= NodeInfo::MGM);
+
+  /**
+   * flush_read_buffer() is used as part of a read_pseudo-FLUSH_AI.
+   * In these cases we are sending two TRANSID_AI results pr row:
+   * One goes to the API, the other to the SPJ node which (currently)
+   * is the only user of FLUSH_AI.
+   * 'read_length' is reported to LQH, which use it to control the 
+   * 'batch_bytes_size' sent to the API. Thus, read_length should be 
+   * counted when not 'is_api.
+   */
+  if (is_api)
+  {
+    req_struct->read_length = len;
+  }
 }
 
 Uint32