支持mysqli扩展的监控；./configure --enable-mysqli=yes来启用对mysqli的监控支持

config.m4

 PHP_ARG_ENABLE(skywalking, whether to enable skywalking support,
 [  --enable-skywalking           Enable skywalking support])
 
+PHP_ARG_ENABLE(mysqli, whether to enable mysqli support,
+[  --enable-mysqli           Enable mysqli support], no, no)
+
 if test "$PHP_SKYWALKING" != "no"; then
   PHP_NEW_EXTENSION(skywalking, \
       skywalking.c \
@@ -8,3 +11,7 @@ if test "$PHP_SKYWALKING" != "no"; then
       encode.c \
   , $ext_shared,, -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1)
 fi
+
+if test "$PHP_MYSQLI" != "no"; then
+    AC_DEFINE(SKYWALKING_ENABLED_MYSQLI, 1, [Enable skywalking support])
+fi

skywalking.c

@@ -249,6 +249,10 @@ ZEND_API void sky_execute_internal(zend_execute_data *execute_data, zval *return
             zf->common.scope->name) : NULL;
     const char *function_name = zf->common.function_name == NULL ? NULL : ZSTR_VAL(zf->common.function_name);
 
+#ifdef SKYWALKING_ENABLED_MYSQLI
+    int is_mysqli_function = 0;
+#endif
+
     char *operationName = NULL;
     char *component = NULL;
     if (class_name != NULL) {
@@ -274,7 +278,33 @@ ZEND_API void sky_execute_internal(zend_execute_data *execute_data, zval *return
                 strcat(operationName, function_name);
             }
         }
+#ifdef SKYWALKING_ENABLED_MYSQLI
+        if (strcmp(class_name, "mysqli") == 0) {
+            if (strcmp(function_name, "query") == 0) {
+                component = (char *) emalloc(strlen("mysqli") + 1);
+                strcpy(component, "mysqli");
+                operationName = (char *) emalloc(strlen(class_name) + strlen(function_name) + 3);
+                strcpy(operationName, class_name);
+                strcat(operationName, "->");
+                strcat(operationName, function_name);
+            }
+        }
+#endif
     } else if (function_name != NULL) {
+#ifdef SKYWALKING_ENABLED_MYSQLI
+        if (strcmp(function_name, "mysqli_query") == 0) {
+            class_name = "mysqli";
+            function_name = "query";
+            component = (char *) emalloc(strlen(class_name) + 1);
+            strcpy(component, class_name);
+            operationName = (char *) emalloc(strlen(class_name) + strlen(function_name) + 3);
+            strcpy(operationName, class_name);
+            strcat(operationName, "->");
+            strcat(operationName, function_name);
+
+            is_mysqli_function = 1;
+        }
+#endif
     }
 
     if (operationName != NULL) {
@@ -324,8 +354,27 @@ ZEND_API void sky_execute_internal(zend_execute_data *execute_data, zval *return
                     add_assoc_string(&tags, "db.data_source", (char *) stmt->dbh->data_source);
                 }
             }
+        } else if (function_name != NULL) {
+            #ifdef SKYWALKING_ENABLED_MYSQLI
+                if (strcmp(class_name, "mysqli") == 0 && strcmp(function_name, "query") == 0) {
+                    add_assoc_string(&tags, "db.type", "mysqli");
+                    // params
+                    uint32_t arg_count = ZEND_CALL_NUM_ARGS(execute_data);
+                    if (arg_count) {
+                        zval *p = is_mysqli_function ? ZEND_CALL_ARG(execute_data, 2) : ZEND_CALL_ARG(execute_data, 1);
+                        //db.statement
+                        switch (Z_TYPE_P(p)) {
+                            case IS_STRING:
+                                add_assoc_string(&tags, "db.statement", Z_STRVAL_P(p));
+                                break;
+
+                        }
+                    }
+                }
+            #endif
         }
 
+
         zval temp;
         zval *spans = NULL;
         zval *span_id = NULL;
@@ -1304,9 +1353,11 @@ PHP_MINIT_FUNCTION (skywalking) {
             return SUCCESS;
         }
 
+        // 用户自定义函数执行器(php脚本定义的类、函数)
         ori_execute_ex = zend_execute_ex;
         zend_execute_ex = sky_execute_ex;
 
+        // 内部函数执行器(c语言定义的类、函数)
         ori_execute_internal = zend_execute_internal;
         zend_execute_internal = sky_execute_internal;