From a5637a311c8d92a412a2c2d21168952b3a0f9971 Mon Sep 17 00:00:00 2001
From: Johan Wikman <johan.wikman@mariadb.com>
Date: Thu, 18 May 2017 11:49:27 +0300
Subject: [PATCH] MXS-1196: Recognize builtin Oracle functions

---
 query_classifier/qc_sqlite/builtin_functions.c | 18 +++++++++++++++++-
 query_classifier/qc_sqlite/builtin_functions.h |  2 +-
 query_classifier/qc_sqlite/qc_sqlite.c         |  2 +-
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/query_classifier/qc_sqlite/builtin_functions.c b/query_classifier/qc_sqlite/builtin_functions.c
index 37fde1477..f529b26d7 100644
--- a/query_classifier/qc_sqlite/builtin_functions.c
+++ b/query_classifier/qc_sqlite/builtin_functions.c
@@ -368,6 +368,16 @@ static const char* BUILTIN_FUNCTIONS[] =
 
 const size_t N_BUILTIN_FUNCTIONS = sizeof(BUILTIN_FUNCTIONS) / sizeof(BUILTIN_FUNCTIONS[0]);
 
+
+static const char* ORACLE_FUNCTIONS[] =
+{
+    "nvl",
+    "nvl2"
+};
+
+const size_t N_ORACLE_FUNCTIONS = sizeof(ORACLE_FUNCTIONS) / sizeof(ORACLE_FUNCTIONS[0]);
+
+
 // NOTE: sort_compare and search_compare are not identical, so don't
 // NOTE: optimize either of them away.
 static int sort_compare(const void* key, const void* value)
@@ -389,6 +399,7 @@ void init_builtin_functions()
     ss_dassert(!unit.inited);
 
     qsort(BUILTIN_FUNCTIONS, N_BUILTIN_FUNCTIONS, sizeof(char*), sort_compare);
+    qsort(ORACLE_FUNCTIONS, N_ORACLE_FUNCTIONS, sizeof(char*), sort_compare);
 
     unit.inited = true;
 }
@@ -399,11 +410,16 @@ void finish_builtin_functions()
     unit.inited = false;
 }
 
-bool is_builtin_readonly_function(const char* key)
+bool is_builtin_readonly_function(const char* key, bool check_oracle)
 {
     ss_dassert(unit.inited);
 
     char* value = bsearch(key, BUILTIN_FUNCTIONS, N_BUILTIN_FUNCTIONS, sizeof(char*), search_compare);
 
+    if (!value && check_oracle)
+    {
+        value = bsearch(key, ORACLE_FUNCTIONS, N_ORACLE_FUNCTIONS, sizeof(char*), search_compare);
+    }
+
     return value ? true : false;
 }
diff --git a/query_classifier/qc_sqlite/builtin_functions.h b/query_classifier/qc_sqlite/builtin_functions.h
index 9c0da9e47..92c4159ff 100644
--- a/query_classifier/qc_sqlite/builtin_functions.h
+++ b/query_classifier/qc_sqlite/builtin_functions.h
@@ -14,7 +14,7 @@ extern "C" {
 void init_builtin_functions();
 void finish_builtin_functions();
 
-bool is_builtin_readonly_function(const char* zToken);
+bool is_builtin_readonly_function(const char* zToken, bool check_oracle);
 
 #ifdef __cplusplus
 }
diff --git a/query_classifier/qc_sqlite/qc_sqlite.c b/query_classifier/qc_sqlite/qc_sqlite.c
index fb3da873d..ea48b0a39 100644
--- a/query_classifier/qc_sqlite/qc_sqlite.c
+++ b/query_classifier/qc_sqlite/qc_sqlite.c
@@ -1187,7 +1187,7 @@ static void update_field_infos(QC_SQLITE_INFO* info,
                 {
                     info->type_mask |= (QUERY_TYPE_READ | QUERY_TYPE_MASTER_READ);
                 }
-                else if (!is_builtin_readonly_function(zToken))
+                else if (!is_builtin_readonly_function(zToken, this_unit.sql_mode == QC_SQL_MODE_ORACLE))
                 {
                     info->type_mask |= QUERY_TYPE_WRITE;
                 }