feat: add hello() function

[nautaa]

Task Description

add hello() function.

obclient> select hello();
+---------------+
| hello()       |
+---------------+
| Hello, World! |
+---------------+
1 row in set (0.01 sec)

Solution Description

Passed Regressions

Upgrade Compatibility

Other Information

Release Note

[CLAassistant]

All committers have signed the CLA.

[xzhseh]

A kindly notice for the environment setup.

1. Please ensure your disk space is enough (i.e., > 35 GB), otherwise it may not be successfully compiled.
2. Github dev container does NOT work for me. (e.g., strange authentication errors.) You will want to either use a good linux server / vm or a local linux machine for the compilation and future deploying.
3. Based on the number and performance of your CPU, it may take a long time to compile for the first time. (i.e., approximately 2 hours for github dev container's configuration) If you're using a virtual machine, be sure to scale up the number of CPU cores.

[caifeizhi]

Thank you for the suggestion.@xzhseh

Please ensure your disk space is enough (i.e., > 35 GB), otherwise it may not be successfully compiled.

I suggest either adding it to the compilation manual or finding a way to display the size of the intermediate artifacts in the compilation job.

Github dev container does NOT work for me. (e.g., strange authentication errors.) You will want to either use a good linux server / vm or a local linux machine for the compilation and future deploying.

Is there any more information available so that we can help you with a workaround or add it to the FAQ?

Based on the number and performance of your CPU, it may take a long time to compile for the first time. (i.e., approximately 2 hours for github dev container's configuration) If you're using a virtual machine, be sure to scale up the number of CPU cores.

Are there any statistics available for the compilation node's time consumption, such as dependency downloads and compilation? We expect that it should be completed within an hour in the devcontainer, based on the current compilation time statistics from GitHub Actions.

[xzhseh]

Is there any more information available so that we can help you with a workaround or add it to the FAQ?

The basic compilation before deploying works fine, though it will take a long time compared to local machine. The problem arises when trying to executing the initial sql script. Specifically the authentication of the client side.

Execute initialize sql x
[ERROR] Failed to Excute ./init_for_ce.sql: ERROR 1045 (42000): Access denied for user 'root'@'xxx.xxx.xxx.xxx' (using password: NO)

Note that the two ports (10000 & 10001) have been successfully set up though the sql could not execute, and when trying to connect to the server via obclient, the same authentication error appears.

I later changed to my local linux vm, and it works just fine.

Are there any statistics available for the compilation node's time consumption, such as dependency downloads and compilation?

For the dependency downloads, the llvm@11 takes most of the time (approximately around 20 ~ 40 minutes).
The compilation takes around 2 hours for me.

Also note that the dev container may unintentionally restart during the process, thus I'd suggest using your own server / local machine for compilation.