From 1034cc51be9a766903ae984b7b707cfafe1e24fa Mon Sep 17 00:00:00 2001
From: Johan Wikman <johan.wikman@mariadb.com>
Date: Mon, 19 Jun 2017 11:21:41 +0300
Subject: [PATCH] MXS-1249: Qc, allow setting the server version

In the case of qc_sqlite, the server version may affect how statements
are parsed.
---
 include/maxscale/query_classifier.h           | 42 +++++++++++++++++++
 .../qc_mysqlembedded/qc_mysqlembedded.cc      | 26 ++++++++++++
 query_classifier/qc_sqlite/qc_sqlite.c        | 28 +++++++++++++
 server/core/query_classifier.cc               | 16 +++++++
 4 files changed, 112 insertions(+)

diff --git a/include/maxscale/query_classifier.h b/include/maxscale/query_classifier.h
index f10ff0213..ff36205d9 100644
--- a/include/maxscale/query_classifier.h
+++ b/include/maxscale/query_classifier.h
@@ -373,6 +373,27 @@ typedef struct query_classifier
      *         exhaustion or equivalent.
      */
     int32_t (*qc_get_preparable_stmt)(GWBUF* stmt, GWBUF** preparable_stmt);
+
+    /**
+     * Set the version of the server. The version may affect how a statement
+     * is classified. Note that the server version is maintained separately
+     * for each thread.
+     *
+     * @param major  The major version.
+     * @param minor  The minor version.
+     * @param patch  The patch version.
+     */
+    void (*qc_set_server_version)(uint32_t major, uint32_t minor, uint32_t patch);
+
+    /**
+     * Get the thread specific version assumed of the server. If the version has
+     * not been set, all values are 0.
+     *
+     * @param major  The major version.
+     * @param minor  The minor version.
+     * @param patch  The patch version.
+     */
+    void (*qc_get_server_version)(uint32_t* major, uint32_t* minor, uint32_t* patch);
 } QUERY_CLASSIFIER;
 
 /**
@@ -758,4 +779,25 @@ const char* qc_type_to_string(qc_query_type_t type);
  */
 char* qc_typemask_to_string(uint32_t typemask);
 
+/**
+ * Set the version of the server. The version may affect how a statement
+ * is classified. Note that the server version is maintained separately
+ * for each thread.
+ *
+ * @param major  The major version.
+ * @param minor  The minor version.
+ * @param patch  The patch version.
+ */
+void qc_set_server_version(uint32_t major, uint32_t minor, uint32_t patch);
+
+/**
+ * Get the thread specific version assumed of the server. If the version has
+ * not been set, all values are 0.
+ *
+ * @param major  The major version.
+ * @param minor  The minor version.
+ * @param patch  The patch version.
+ */
+void qc_get_server_version(uint32_t* major, uint32_t* minor, uint32_t* patch);
+
 MXS_END_DECLS
diff --git a/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc b/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc
index df11b1b01..77597fc4d 100644
--- a/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc
+++ b/query_classifier/qc_mysqlembedded/qc_mysqlembedded.cc
@@ -94,6 +94,16 @@ typedef struct parsing_info_st
 #endif
 } parsing_info_t;
 
+static thread_local struct
+{
+    // The version information is not used; the embedded library parses according
+    // to the version of the embedded library it has been linked with. However, we
+    // need to store the information so that qc_[get|set]_server_version will work.
+    uint32_t version_major;
+    uint32_t version_minor;
+    uint32_t version_patch;
+} this_thread;
+
 #define QTYPE_LESS_RESTRICTIVE_THAN_WRITE(t) (t<QUERY_TYPE_WRITE ? true : false)
 
 static THD* get_or_create_thd_for_parsing(MYSQL* mysql, char* query_str);
@@ -2590,6 +2600,20 @@ int32_t qc_mysql_get_function_info(GWBUF* buf,
     return QC_RESULT_OK;
 }
 
+void qc_mysql_set_server_version(uint32_t major, uint32_t minor, uint32_t patch)
+{
+    this_thread.version_major = major;
+    this_thread.version_minor = minor;
+    this_thread.version_patch = patch;
+}
+
+void qc_mysql_get_server_version(uint32_t* major, uint32_t* minor, uint32_t* patch)
+{
+    *major = this_thread.version_major;
+    *minor = this_thread.version_minor;
+    *patch = this_thread.version_patch;
+}
+
 namespace
 {
 
@@ -2743,6 +2767,8 @@ extern "C"
             qc_mysql_get_field_info,
             qc_mysql_get_function_info,
             qc_mysql_get_preparable_stmt,
+            qc_mysql_set_server_version,
+            qc_mysql_get_server_version,
         };
 
         static MXS_MODULE info =
diff --git a/query_classifier/qc_sqlite/qc_sqlite.c b/query_classifier/qc_sqlite/qc_sqlite.c
index 2f561d1d0..4e6d56ee5 100644
--- a/query_classifier/qc_sqlite/qc_sqlite.c
+++ b/query_classifier/qc_sqlite/qc_sqlite.c
@@ -114,6 +114,9 @@ static thread_local struct
     bool initialized;
     sqlite3* db;      // Thread specific database handle.
     QC_SQLITE_INFO* info;
+    uint32_t version_major;
+    uint32_t version_minor;
+    uint32_t version_patch;
 } this_thread;
 
 /**
@@ -2907,6 +2910,8 @@ static int32_t qc_sqlite_get_canonical(GWBUF* query, char** canonical);
 static int32_t qc_sqlite_query_has_clause(GWBUF* query, int32_t* has_clause);
 static int32_t qc_sqlite_get_database_names(GWBUF* query, char*** names, int* sizep);
 static int32_t qc_sqlite_get_preparable_stmt(GWBUF* stmt, GWBUF** preparable_stmt);
+static void qc_sqlite_set_server_version(uint32_t major, uint32_t minor, uint32_t patch);
+static void qc_sqlite_get_server_version(uint32_t* major, uint32_t* minor, uint32_t* patch);
 
 static bool get_key_and_value(char* arg, const char** pkey, const char** pvalue)
 {
@@ -3080,6 +3085,9 @@ static int32_t qc_sqlite_thread_init(void)
             this_thread.info = NULL;
 
             this_thread.initialized = true;
+            this_thread.version_major = 0;
+            this_thread.version_minor = 0;
+            this_thread.version_patch = 0;
         }
         else
         {
@@ -3522,6 +3530,24 @@ int32_t qc_sqlite_get_preparable_stmt(GWBUF* stmt, GWBUF** preparable_stmt)
     return rv;
 }
 
+static void qc_sqlite_set_server_version(uint32_t major, uint32_t minor, uint32_t patch)
+{
+    QC_TRACE();
+
+    this_thread.version_major = major;
+    this_thread.version_minor = minor;
+    this_thread.version_patch = patch;
+}
+
+static void qc_sqlite_get_server_version(uint32_t* major, uint32_t* minor, uint32_t* patch)
+{
+    QC_TRACE();
+
+    *major = this_thread.version_major;
+    *minor = this_thread.version_minor;
+    *patch = this_thread.version_patch;
+}
+
 /**
  * EXPORTS
  */
@@ -3548,6 +3574,8 @@ MXS_MODULE* MXS_CREATE_MODULE()
         qc_sqlite_get_field_info,
         qc_sqlite_get_function_info,
         qc_sqlite_get_preparable_stmt,
+        qc_sqlite_set_server_version,
+        qc_sqlite_get_server_version,
     };
 
     static MXS_MODULE info =
diff --git a/server/core/query_classifier.cc b/server/core/query_classifier.cc
index aa69e2ddf..6da6f60bd 100644
--- a/server/core/query_classifier.cc
+++ b/server/core/query_classifier.cc
@@ -901,3 +901,19 @@ uint32_t qc_get_trx_type_mask(GWBUF* stmt)
 {
     return qc_get_trx_type_mask_using(stmt, qc_trx_parse_using);
 }
+
+void qc_set_server_version(uint32_t major, uint32_t minor, uint32_t patch)
+{
+    QC_TRACE();
+    ss_dassert(classifier);
+
+    classifier->qc_set_server_version(major, minor, patch);
+}
+
+void qc_get_server_version(uint32_t* major, uint32_t* minor, uint32_t* patch)
+{
+    QC_TRACE();
+    ss_dassert(classifier);
+
+    classifier->qc_get_server_version(major, minor, patch);
+}