Fix performance regression due to QI for DDL

This check-in omits object UIDs from query plans for the tables
SB_HISTOGRAMS and SB_HISTOGRAMS_INTERVALS. Previously, when the
code generator tried to add the object UIDs for these, it had to
make a special query to the metadata, since the corresponding
internal cached structure omitted object UIDs when they were
created via methods like Generator::createVirtualTableDesc. The
special query to lookup these object UIDs was shown to be
responsible for a large pathlengh regression.

Change-Id: Id5046c5c55a4fc8dd2ba3f891449ea87d35a5534
Closes-Bug: #1398600

sql/generator/GenRelExeUtil.cpp

@@ -5518,7 +5518,7 @@ short ExeUtilHbaseCoProcAggr::codeGen(Generator * generator)
   TableDesc *tableDesc = getUtilTableDesc();
   if (tableDesc->getNATable()->isSeabaseTable())
   {
-    if (!tableDesc->getNATable()->isSeabaseMDTable())
+    if (tableDesc->getNATable()->isEnabledForDDLQI())
       generator->objectUids().insert(
         tableDesc->getNATable()->objectUid().get_value());
   }

sql/generator/GenRelScan.cpp

@@ -165,7 +165,7 @@ short Describe::codeGen(Generator * generator)
     CmpCommon::diags()->rewind(daMark, TRUE);
 
     if (describedTable && describedTable->isSeabaseTable() &&
-        (!describedTable->isSeabaseMDTable()))
+        describedTable->isEnabledForDDLQI())
       generator->objectUids().insert(
         describedTable->objectUid().get_value());
   }
@@ -2546,7 +2546,7 @@ short HbaseAccess::codeGen(Generator * generator)
 
       if (getTableDesc()->getNATable()->isSQLMXAlignedTable())
         hbasescan_tdb->setAlignedFormat(TRUE);
-      if (!getTableDesc()->getNATable()->isSeabaseMDTable())
+      if (getTableDesc()->getNATable()->isEnabledForDDLQI())
         generator->objectUids().insert(
           getTableDesc()->getNATable()->objectUid().get_value());
     }
@@ -2798,7 +2798,7 @@ short HbaseAccessCoProcAggr::codeGen(Generator * generator)
   if (getTableDesc()->getNATable()->isSeabaseTable())
   {
     hbasescan_tdb->setSQHbaseTable(TRUE);
-    if (!getTableDesc()->getNATable()->isSeabaseMDTable())
+    if (getTableDesc()->getNATable()->isEnabledForDDLQI())
       generator->objectUids().insert(
         getTableDesc()->getNATable()->objectUid().get_value());
   }

sql/generator/GenRelUpdate.cpp

@@ -1277,7 +1277,7 @@ short HbaseDelete::codeGen(Generator * generator)
 	  (NOT noCheck()))
 	hbasescan_tdb->setHbaseSqlIUD(TRUE);
 
-      if (!getTableDesc()->getNATable()->isSeabaseMDTable())
+      if (getTableDesc()->getNATable()->isEnabledForDDLQI())
         generator->objectUids().insert(
           getTableDesc()->getNATable()->objectUid().get_value());
     }
@@ -2086,7 +2086,7 @@ short HbaseUpdate::codeGen(Generator * generator)
       if (CmpCommon::getDefault(HBASE_SQL_IUD_SEMANTICS) == DF_ON)
 	hbasescan_tdb->setHbaseSqlIUD(TRUE);
 
-      if (!getTableDesc()->getNATable()->isSeabaseMDTable())
+      if (getTableDesc()->getNATable()->isEnabledForDDLQI())
         generator->objectUids().insert(
           getTableDesc()->getNATable()->objectUid().get_value());
     }
@@ -2724,7 +2724,7 @@ short HbaseInsert::codeGen(Generator *generator)
 
 
       }
-      if (!getTableDesc()->getNATable()->isSeabaseMDTable())
+      if (getTableDesc()->getNATable()->isEnabledForDDLQI())
         generator->objectUids().insert(
           getTableDesc()->getNATable()->objectUid().get_value());
     }

sql/optimizer/NATable.cpp

@@ -6790,6 +6790,30 @@ void NATable::lookupObjectUid()
     objectUID_ = ::lookupObjectUid(qualName, objectType_);
 }
 
+bool NATable::isEnabledForDDLQI() const
+{
+  if (isSeabaseMD_ || isSMDTable_)
+    return false;
+  else 
+  {
+    if (objectUID_.get_value() == 0)
+    {
+      // Looking up object UIDs at code-gen time was shown to cause
+      // more than 10% performance regression in YCSB benchmark. In
+      // that investigation, we learned that metadata and histogram 
+      // NATables would have no object UID at code-gen and would 
+      // require the lookup.  We're pretty sure these are the only 
+      // types of tables but will abend here otherwise. If this 
+      // causes problems, the envvar below can be used as a 
+      // temporary workaround. 
+      char *noAbendOnLp1398600 = getenv("NO_ABEND_ON_LP_1398600");
+      if (!noAbendOnLp1398600 || *noAbendOnLp1398600 == '0')
+        abort();
+    }
+    return true;
+  }
+}
+
 NATable::~NATable()
 {
   // remove the map entries of associated table identifers in

sql/optimizer/NATable.h

@@ -510,7 +510,8 @@ class NATable : public NABasicObject
     return objectUID_;
   }
 
-  void lookupObjectUid();    // Used to look up uid on demand for metadata tables
+  void lookupObjectUid();  // Used to look up uid on demand for metadata tables
+  bool isEnabledForDDLQI() const;
 
   const ComObjectType &getObjectType() const { return objectType_; }
 

sql/regress/executor/EXPECTED122

@@ -17,11 +17,17 @@
 
 --- SQL command prepared.
 >>
+>>update statistics for table t122t1 on every column;
+
+--- SQL operation complete.
+>>
 >>obey TEST122(uid_in_plan);
 >>log;
 look for one uid only
   ObjectUIDs .......
 look for more than one uid
+>>-- lp 1398600 -- test that there are no object UIDs for MD or histograms
+>>log;
 >>
 >>
 >>execute s1;
@@ -37,6 +43,8 @@ look for more than one uid
 look for one uid only
   ObjectUIDs .......
 look for more than one uid
+>>-- lp 1398600 -- test that there are no object UIDs for MD or histograms
+>>log;
 >>
 >>
 >>execute s1;
@@ -53,7 +61,7 @@ A
 >>invoke t122t1;
 
 -- Definition of Trafodion table TRAFODION.SCH.T122T1
--- Definition current  Wed Nov 19 17:36:02 2014
+-- Definition current  Wed Dec  3 17:47:33 2014
 
   (
     A                                INT NO DEFAULT NOT NULL NOT DROPPABLE
@@ -105,7 +113,7 @@ A
 >>execute s3;
 
 -- Definition of Trafodion table TRAFODION.SCH.T122T1
--- Definition current  Wed Nov 19 17:36:02 2014
+-- Definition current  Wed Dec  3 17:47:33 2014
 
   (
     A                                INT NO DEFAULT NOT NULL NOT DROPPABLE
@@ -214,7 +222,7 @@ iv
 
 
 -- Definition of Trafodion table TRAFODION.SCH.T122T1
--- Definition current  Wed Nov 19 17:36:17 2014
+-- Definition current  Wed Dec  3 17:48:08 2014
 
   (
     A                                CHAR(4) CHARACTER SET ISO88591 COLLATE

sql/regress/executor/TEST122

@@ -52,6 +52,8 @@ prepare s1 from insert into t122t1 values
 , (1)
 ;
 
+update statistics for table t122t1 on every column;
+
 obey TEST122(uid_in_plan);
 
 execute s1;
@@ -321,6 +323,15 @@ sh grep "^  ObjectUIDs .* [1-9][0-9]*$" PLAN122 | cut -c 1-20 >> LOG122;
 sh echo "look for more than one uid" >> LOG122; 
 sh grep "^  ObjectUIDs .* [1-9][0-9]*," PLAN122;
 log LOG122;
+-- lp 1398600 -- test that there are no object UIDs for MD or histograms
+log;
+log PLAN122 clear;
+explain select * from SB_HISTOGRAMS;
+explain select * from SB_HISTOGRAM_INTERVALS;
+explain select * from "_MD_".OBJECTS;
+log;
+sh grep "^  ObjectUIDs .* [1-9][0-9]*" PLAN122 | cut -c 1-20  >> LOG122;
+log LOG122;
 
 ?section drop_tab
 

sql/sqlcomp/CmpMain.cpp

@@ -1111,9 +1111,8 @@ void CmpMain:: getAndProcessAnySiKeys(TimeVal begTime)
 #endif
       ;
 
-   int numRetriesRemaining = 16;
    Int32 sqlcode = -1;
-   while (sqlcode < 0 && numRetriesRemaining)
+   while (sqlcode < 0)
    {
      SQL_QIKEY sikKeyArray[arraySize];
 
@@ -1129,11 +1128,11 @@ void CmpMain:: getAndProcessAnySiKeys(TimeVal begTime)
      }
      else if (sqlcode < 0)
      {
-       // The CLI sends messages to RMS processes. The only errors we
-       // would expect would be retryable, as these processes are
-       // persistent.
-       sleep(1);
-       numRetriesRemaining--;
+       // No other error is expected. The CLI call 
+       // simply accesses memory. If the implementation
+       // changes, then the abort below should remind us
+       // to change the error handling.
+       abort();
      }
      else if ( returnedNumSiKeys > 0 )
      {