From 09c89d94125014f0c2d506c2e6e4dc7a42cd89bd Mon Sep 17 00:00:00 2001
From: Haojun Liao <hjliao@taosdata.com>
Date: Tue, 7 Jul 2020 12:59:24 +0800
Subject: [PATCH] [td-225] handle the case where no qualified ts exists during
 join query process.

---
 src/client/src/tscSubquery.c         | 58 +++++++++-------------------
 tests/script/general/parser/join.sim | 12 ++++++
 2 files changed, 30 insertions(+), 40 deletions(-)

diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 0243d115f0..c052482edf 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -57,10 +57,15 @@ static int64_t doTSBlockIntersect(SSqlObj* pSql, SJoinSupporter* pSupporter1, SJ
   pSubQueryInfo1->tsBuf = output1;
   pSubQueryInfo2->tsBuf = output2;
 
+  // no result generated, return directly
+  if (pSupporter1->pTSBuf == NULL || pSupporter2->pTSBuf == NULL) {
+    tscDebug("%p at least one ts-comp is empty, 0 for secondary query after ts blocks intersecting", pSql);
+    return 0;
+  }
+
   tsBufResetPos(pSupporter1->pTSBuf);
   tsBufResetPos(pSupporter2->pTSBuf);
 
-  // TODO add more details information
   if (!tsBufNextPos(pSupporter1->pTSBuf)) {
     tsBufFlush(output1);
     tsBufFlush(output2);
@@ -420,43 +425,6 @@ static void updateQueryTimeRange(SQueryInfo* pQueryInfo, STimeWindow* win) {
   pQueryInfo->window = *win;
 }
 
-static UNUSED_FUNC void tSIntersectionAndLaunchSecQuery(SJoinSupporter* pSupporter, SSqlObj* pSql) {
-  SSqlObj* pParentSql = pSupporter->pObj;
-  SQueryInfo* pParentQueryInfo = tscGetQueryInfoDetail(&pParentSql->cmd, pParentSql->cmd.clauseIndex);
-  
-//  if (tscNonOrderedProjectionQueryOnSTable(pParentQueryInfo, 0)) {
-//    STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
-//    assert(pQueryInfo->numOfTables == 1);
-//
-//    // for projection query, need to try next vnode
-////        int32_t totalVnode = pTableMetaInfo->pMetricMeta->numOfVnodes;
-//    int32_t totalVnode = 0;
-//    if ((++pTableMetaInfo->vgroupIndex) < totalVnode) {
-//      tscDebug("%p current vnode:%d exhausted, try next:%d. total vnode:%d. current numOfRes:%d", pSql,
-//               pTableMetaInfo->vgroupIndex - 1, pTableMetaInfo->vgroupIndex, totalVnode, pRes->numOfTotal);
-//
-//      pSql->cmd.command = TSDB_SQL_SELECT;
-//      pSql->fp = tscJoinQueryCallback;
-//      tscProcessSql(pSql);
-//
-//      return;
-//    }
-//  }
-
-    SJoinSupporter* p1 = pParentSql->pSubs[0]->param;
-    SJoinSupporter* p2 = pParentSql->pSubs[1]->param;
-    
-    STimeWindow win = TSWINDOW_INITIALIZER;
-    int64_t num = doTSBlockIntersect(pParentSql, p1, p2, &win);
-    if (num <= 0) {  // no result during ts intersect
-      tscDebug("%p free all sub SqlObj and quit", pParentSql);
-      freeJoinSubqueryObj(pParentSql);
-    } else {
-      updateQueryTimeRange(pParentQueryInfo, &win);
-      tscLaunchRealSubqueries(pParentSql);
-    }
-}
-
 int32_t tscCompareTidTags(const void* p1, const void* p2) {
   const STidTags* t1 = (const STidTags*) varDataVal(p1);
   const STidTags* t2 = (const STidTags*) varDataVal(p2);
@@ -713,9 +681,16 @@ static void tidTagRetrieveCallback(void* param, TAOS_RES* tres, int32_t numOfRow
   SArray *s1 = NULL, *s2 = NULL;
   getIntersectionOfTableTuple(pQueryInfo, pParentSql, &s1, &s2);
   if (taosArrayGetSize(s1) == 0 || taosArrayGetSize(s2) == 0) {  // no results,return.
-    tscDebug("%p free all sub SqlObj and quit", pParentSql);
+    taosArrayDestroy(s1);
+    taosArrayDestroy(s2);
+
+    tscDebug("%p tag intersect does not generated qualified tables for join, free all sub SqlObj and quit", pParentSql);
     freeJoinSubqueryObj(pParentSql);
 
+    // set no result command
+    pParentSql->cmd.command = TSDB_SQL_RETRIEVE_EMPTY_RESULT;
+    (*pParentSql->fp)(pSql->param, pParentSql, 0);
+
   } else {
     // proceed to for ts_comp query
     SSqlCmd* pSubCmd1 = &pParentSql->pSubs[0]->cmd;
@@ -846,7 +821,10 @@ static void tsCompRetrieveCallback(void* param, TAOS_RES* tres, int32_t numOfRow
   if (num <= 0) {  // no result during ts intersect
     tscDebug("%p no results generated in ts intersection, free all sub SqlObj and quit", pParentSql);
     freeJoinSubqueryObj(pParentSql);
-    
+
+    // set no result command
+    pParentSql->cmd.command = TSDB_SQL_RETRIEVE_EMPTY_RESULT;
+    (*pParentSql->fp)(pSql->param, pParentSql, 0);
     return;
   }
 
diff --git a/tests/script/general/parser/join.sim b/tests/script/general/parser/join.sim
index 1bce6f1950..69932e1e1c 100644
--- a/tests/script/general/parser/join.sim
+++ b/tests/script/general/parser/join.sim
@@ -447,4 +447,16 @@ sql insert into um2 using m2 tags(9) values(1000001, 10)(2000000, 20);
 
 sql_error select count(*) from m1,m2 where m1.a=m2.a and m1.ts=m2.ts;
 
+#empty table join test, add for no result join test
+create database ux1;
+use ux1;
+create table m1(ts timestamp, k int) tags(a binary(12), b int);
+create table tm0 using m1 tags('abc', 1);
+
+create table m2(ts timestamp, k int) tags(a int, b binary(12));
+create table tm2 using m2 tags(2, 'abc');
+select count(*) from tm0, tm2 where tm0.ts=tm2.ts;
+select count(*) from m1, m2 where m1.ts=m2.ts and m1.b=m2.a
+drop database ux1;
+
 system sh/exec.sh -n dnode1 -s stop -x SIGINT
\ No newline at end of file
-- 
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