请求指导Windows Server 2016 64位下MySQL正确安装使用lib_mysqludf_sys

Hey there, I totally get how frustrating this is—64-bit lib_mysqludf_sys resources are super scarce, and even when you find one, getting it to play nice with MySQL can feel like hitting a wall. Let’s break down how to fix this crash issue step by step.

First: Verify Your DLL’s Compatibility #

The most common cause of crashes here is a mismatched or corrupted DLL. Let’s confirm it’s valid:

• Check architecture: Use the Windows dumpbin tool (part of Visual Studio Build Tools) to confirm the DLL is 64-bit. Run this command in a command prompt:

  dumpbin /headers lib_mysqludf_sys.dll | findstr "machine"
  

  You should see machine (x64) in the output. If it says x86, that’s definitely the problem—you need a true 64-bit build.
• Check dependencies: Use Dependency Walker (or the newer Dependencies tool) to scan the DLL for missing system libraries (like msvcr120.dll or vcruntime140.dll). Missing runtime files will cause MySQL to crash when trying to load the UDF.
• Match MySQL version: UDF interfaces change between MySQL versions (e.g., 5.7 vs 8.0). Make sure the DLL was built for your exact MySQL version. If you’re unsure, compiling your own is the safest bet (more on that later).

Second: Re-Check Your Installation Steps #

Even small missteps here can lead to crashes. Let’s walk through the correct setup:

1. Place the DLL in the right directory: First, find your MySQL plugin folder with this SQL query:

   SHOW VARIABLES LIKE 'plugin_dir';
   

   Copy the DLL into this folder, then make sure the MySQL service account (usually Network Service) has read/execute permissions on the DLL file.
2. Register the functions correctly: Run these SQL commands to create the UDFs (don’t skip any—missing functions can cause unexpected crashes):

   CREATE FUNCTION sys_exec RETURNS INT SONAME 'lib_mysqludf_sys.dll';
   CREATE FUNCTION sys_eval RETURNS STRING SONAME 'lib_mysqludf_sys.dll';
   CREATE FUNCTION sys_get RETURNS STRING SONAME 'lib_mysqludf_sys.dll';
   CREATE FUNCTION sys_set RETURNS INT SONAME 'lib_mysqludf_sys.dll';
   

3. Verify registration: Confirm the functions exist with:

   SELECT * FROM mysql.func WHERE name LIKE 'sys_%';
   

   You should see all four functions listed.

Third: Test Safely to Isolate the Crash #

Before calling your target file, test with a simple command to rule out permission or parameter issues:

• Run a basic file-writing command:

  SELECT sys_exec('echo test > C:\\temp\\udf_test.txt');
  

  If this crashes MySQL, the issue is almost certainly with the DLL itself (corrupted or incompatible). If it works, then the problem is with your target file (permissions, path issues, or the file itself causing a crash when executed by the MySQL service account).
• Check MySQL error logs: Get the log path with:

  SHOW VARIABLES LIKE 'log_error';
  

  Open the log file—crash events will include detailed info (like memory addresses or error codes) that can pinpoint whether it’s a DLL issue, permission problem, or something else.

Fourth: Compile Your Own 64-bit DLL (If All Else Fails) #

If the DLL you got is corrupted or incompatible, compiling from source guarantees compatibility:

1. Grab the official lib_mysqludf_sys source code.
2. Use Visual Studio (match the version your MySQL was compiled with—e.g., MySQL 8.0 uses VS2019) to create a 64-bit DLL project:
   • Add MySQL’s include folder (usually C:\Program Files\MySQL\MySQL Server X.X\include) to your project’s include directories.
   • Add MySQL’s lib folder (usually C:\Program Files\MySQL\MySQL Server X.X\lib) to your project’s library directories.
   • Link against libmysql.lib in the linker settings.
3. Build the 64-bit DLL, then repeat the installation steps above. This should eliminate compatibility issues.

内容的提问来源于stack exchange，提问作者Next World Soft