From aa1b48119730e81c1214bbcb8e285c98d3d4f174 Mon Sep 17 00:00:00 2001
From: Johan Wikman <johan.wikman@gmail.com>
Date: Mon, 24 May 2021 10:54:00 +0300
Subject: [PATCH] MXS-3535 Collect information from ON clause

In the case of qc_sqlite, it is done "precisely", while in the
case of qc_mysqlembedded rather bluntly. Not time well spent
to figure out exactly which pointer chains need to be walked.
---
 .../qc_mysqlembedded/qc_mysqlembedded.cc      | 75 +++++++++++++++++++
 query_classifier/qc_sqlite/qc_sqlite.cc       | 10 +++
 .../qc_sqlite/sqlite-src-3110100/src/parse.y  | 10 ++-
 3 files changed, 92 insertions(+), 3 deletions(-)

diff --git a/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc b/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc
index 5eab45dd1..0a27ee8b0 100644
--- a/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc
+++ b/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc
@@ -71,6 +71,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
+#include <set>
+
+using std::set;
 
 #if MYSQL_VERSION_MAJOR >= 10 && MYSQL_VERSION_MINOR >= 2
 #define CTE_SUPPORTED
@@ -3434,6 +3437,51 @@ static void update_field_infos(parsing_info_t* pi,
     }
 }
 
+namespace
+{
+
+void collect_from_list(set<TABLE_LIST*>& seen, parsing_info_t* pi, SELECT_LEX* select_lex, TABLE_LIST* pList)
+{
+    if (seen.find(pList) != seen.end())
+    {
+        return;
+    }
+
+    seen.insert(pList);
+
+    if (pList->on_expr)
+    {
+        update_field_infos(pi, select_lex, COLLECT_SELECT, pList->on_expr, NULL);
+    }
+
+    if (pList->next_global)
+    {
+        collect_from_list(seen, pi, select_lex, pList->next_global);
+    }
+
+    if (pList->next_local)
+    {
+        collect_from_list(seen, pi, select_lex, pList->next_local);
+    }
+
+    st_nested_join* pJoin = pList->nested_join;
+
+    if (pJoin)
+    {
+        List_iterator<TABLE_LIST> it(pJoin->join_list);
+
+        TABLE_LIST* pList2 = it++;
+
+        while (pList2)
+        {
+            collect_from_list(seen, pi, select_lex, pList2);
+            pList2 = it++;
+        }
+    }
+}
+
+}
+
 int32_t qc_mysql_get_field_info(GWBUF* buf, const QC_FIELD_INFO** infos, uint32_t* n_infos)
 {
     *infos = NULL;
@@ -3474,6 +3522,33 @@ int32_t qc_mysql_get_field_info(GWBUF* buf, const QC_FIELD_INFO** infos, uint32_
 
         update_field_infos(pi, lex, select_lex, NULL);
 
+        set<TABLE_LIST*> seen;
+
+        if (lex->query_tables)
+        {
+            collect_from_list(seen, pi, select_lex, lex->query_tables);
+        }
+
+        List_iterator<TABLE_LIST> it1(select_lex->top_join_list);
+
+        TABLE_LIST* pList = it1++;
+
+        while (pList)
+        {
+            collect_from_list(seen, pi, select_lex, pList);
+            pList = it1++;
+        }
+
+        List_iterator<TABLE_LIST> it2(select_lex->sj_nests);
+
+        /*TABLE_LIST**/ pList = it2++;
+
+        while (pList)
+        {
+            collect_from_list(seen, pi, select_lex, pList);
+            pList = it2++;
+        }
+
         QC_FUNCTION_INFO* fi = NULL;
 
         if ((lex->sql_command == SQLCOM_UPDATE) || (lex->sql_command == SQLCOM_UPDATE_MULTI))
diff --git a/query_classifier/qc_sqlite/qc_sqlite.cc b/query_classifier/qc_sqlite/qc_sqlite.cc
index efaa3b482..0e9eb34fa 100644
--- a/query_classifier/qc_sqlite/qc_sqlite.cc
+++ b/query_classifier/qc_sqlite/qc_sqlite.cc
@@ -1303,6 +1303,11 @@ public:
                                                    pExclude);
                 }
 
+                if (pSrc->a[i].pOn)
+                {
+                    update_field_infos(&aliases, context, 0, pSrc->a[i].pOn, QC_TOKEN_MIDDLE, pExclude);
+                }
+
 #ifdef QC_COLLECT_NAMES_FROM_USING
                 // With this enabled, the affected fields of
                 //    select * from (t1 as t2 left join t1 as t3 using (a)), t1;
@@ -1436,6 +1441,11 @@ public:
                 {
                     update_names_from_srclist(pAliases, pSrc->a[i].pSelect->pSrc);
                 }
+
+                if (pSrc->a[i].pOn)
+                {
+                    update_field_infos(pAliases, 0, 0, pSrc->a[i].pOn, QC_TOKEN_MIDDLE, NULL);
+                }
             }
         }
     }
diff --git a/query_classifier/qc_sqlite/sqlite-src-3110100/src/parse.y b/query_classifier/qc_sqlite/sqlite-src-3110100/src/parse.y
index bba08dc2e..a2b16eac4 100644
--- a/query_classifier/qc_sqlite/sqlite-src-3110100/src/parse.y
+++ b/query_classifier/qc_sqlite/sqlite-src-3110100/src/parse.y
@@ -1615,12 +1615,16 @@ table_reference(A) ::= join_table(X). {
 join_opt ::= .
 join_opt ::= JOIN_KW.
 
-join_table(A) ::= table_reference(X) join_opt JOIN table_reference(Y) join_condition. {
+%type join_condition {ExprSpan}
+%destructor join_condition {sqlite3ExprDelete(pParse->db, $$.pExpr);}
+
+join_table(A) ::= table_reference(X) join_opt JOIN table_reference(Y) join_condition(Z). {
+  Y->a[Y->nSrc - 1].pOn = Z.pExpr;
   A = sqlite3SrcListCat(pParse->db, X, Y);
 }
 
-join_condition ::= ON expr(X). {
-    sqlite3ExprDelete(pParse->db, X.pExpr);
+join_condition(A) ::= ON expr(X). {
+  A = X;
 }
 
 %type escaped_table_reference {SrcList*}