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2022 oceanbase competition

* support build with address sanitizer

using cmake options `-DENALBE_ASAN=ON` to enable address sanitizer

* fix some memory leaks detected by asan

* fix -Wunused-function

* 调整文档格式

优化load data效率

format lex file

Docker 中安装gdb；
删除handler.h 文件；
BplusTree中的比较函数使用deps下公用接口；

修复进程退出时，libevent 无法正常结束循环的BUG

remove unused variable

set response to failure while resolve failed

1. select return all columns;
2. no tuple header now;
3. predicate works now.