1.FE

1.1 Unknown system variable ‘character_set_database’

mysql> status
--------------
mysql  Ver 8.0.25 for Linux on x86_64 (MySQL Community Server - GPL)

Connection id:          0
Current database:
Current user:           'admin'@'192.168.0.xxx'
SSL:                    Not in use
Current pager:          stdout
Using outfile:          ''
Using delimiter:        ;
Server version:         5.7.99 Doris version doris-2.0.8-d083188cdd
Protocol version:       10
Connection:             192.168.0.xxx via TCP/IP
ERROR 1193 (HY000): errCode = 2, detailMessage = Unknown system variable 'character_set_database'
ERROR 2014 (HY000): Commands out of sync; you can't run this command now
Client characterset:    utf8mb4
Server characterset:    utf8mb4
TCP port:               9034
Binary data as:         Hexadecimal
--------------

跟MySQL数据库的版本有关系，可以忽略。

1.2 notify new FE type transfer: UNKNOWN

修改配置文件后，元数据已存在，需要删除元数据：

# 问题
WARN (UNKNOWN fe_6031ab79_c88a_405f_b212_ec8b52178864(-1)|1) 
[Env.notifyNewFETypeTransfer():2421] notify new FE type transfer: UNKNOWN

# 删除元数据
rm -rf doris-meta

1.3 mysql_load_server_secure_path

# 问题
mysql> LOAD DATA INFILE '/path/file.txt' INTO TABLE tableName;
ERROR 1105 (HY000): errCode = 2, 
detailMessage = Load local data from fe local is not enabled. 
If you want to use it, plz set the `mysql_load_server_secure_path` for FE to be a right path.

# fe的配置文件添加路径 /fe/conf/fe.conf
mysql_load_server_secure_path = /path/

指定LOCAL表示读取客户端文件.不指定表示读取FE服务端本地文件. 导入FE本地文件的功能默认是关闭的, 需要在FE节点上设置mysql_load_server_secure_path来指定安全路径, 才能打开该功能。

1.4 Only unique table could be updated

# 问题
java.sql.SQLException: errCode = 2, detailMessage = Only unique table could be updated.

# 主键模型
UNIQUE KEY(`user_id`, `username`)
PROPERTIES (
"enable_unique_key_merge_on_write" = "true"
);

1.5 too many filtered rows

# 问题
Failed to execute sql: java.sql.SQLException: (conn=4) errCode = 2, detailMessage = [INTERNAL_ERROR]too many filtered rows

	0#  std::_Function_handler<void (doris::RuntimeState*, doris::Status*), doris::StreamLoadExecutor::execute_plan_fragment(std::shared_ptr<doris::StreamLoadContext>)::$_0>::_M_invoke(std::_Any_data const&, doris::RuntimeState*&&, doris::Status*&&) at /home/zcp/repo_center/doris_release/doris/be/src/common/status.h:357
	1#  doris::FragmentMgr::_exec_actual(std::shared_ptr<doris::FragmentExecState>, std::function<void (doris::RuntimeState*, doris::Status*)> const&) at /var/local/ldb_toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/unique_ptr.h:360
	2#  std::_Function_handler<void (), doris::FragmentMgr::exec_plan_fragment(doris::TExecPlanFragmentParams const&, std::function<void (doris::RuntimeState*, doris::Status*)> const&)::$_0>::_M_invoke(std::_Any_data const&) at /var/local/ldb_toolchain/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/shared_ptr_base.h:701
	3#  doris::ThreadPool::dispatch_thread() at /home/zcp/repo_center/doris_release/doris/be/src/util/threadpool.cpp:0
	4#  doris::Thread::supervise_thread(void*) at /var/local/ldb_toolchain/bin/../usr/include/pthread.h:562
	5#  ?
	6#  ?
 with load id 92db959a-87e3-4e8a-b34b-5ab0333ce0c0

# 通过使用以下命令查看详细的报错信息
show load warnings where label='92db959a-87e3-4e8a-b34b-5ab0333ce0c0'

Reason: column_name[imei], the length of input is too long than schema. first 32 bytes of input str: [2023-10-10 15:59:14] schema length: 15; actual length: 19; . src line [];

2.BE

2.1 Have not get FE Master heartbeat yet

W0416 09:24:00.378782 3838800 olap_server.cpp:667] Have not get FE Master heartbeat yet

讲BE添加到集群即可：

ALTER SYSTEM ADD BACKEND "be_host_ip:heartbeat_service_port";

2.2 overcommit_memory: 2, expect is 1

这个问题是关于Linux操作系统的内存管理参数overcommit_memory。当overcommit_memory设置为2时，表示允许分配超过物理内存和交换空间总和的内存。而期望的值是1，表示不允许分配超过物理内存和交换空间总和的内存。在这种情况下，内存限制检查将交给Doris Allocator处理，否则即使剩余内存充足，Backend（BE）也可能会崩溃。

# 问题
/proc/sys/vm/overcommit_memory: 2, expect is 1, memory limit check is handed over to Doris Allocator, otherwise BE may crash even with remaining memory

# 解决
echo 1 > /proc/sys/vm/overcommit_memory