Add udp2, an experimental IPC layer implementation

[zhangyue1818]

Fixes #ISSUE_Number

What does this PR do?

Type of Change

• Bug fix (non-breaking change)
• New feature (non-breaking change)
• Breaking change (fix or feature with breaking changes)
• Documentation update

Breaking Changes

Test Plan

• Unit tests added/updated
• Integration tests added/updated
• Passed make installcheck
• Passed make -C src/test installcheck-cbdb-parallel

Impact

Performance:

User-facing changes:

Dependencies:

Checklist

• Followed contribution guide
• Added/updated documentation
• Reviewed code for security implications
• Requested review from cloudberry committers

Additional Context

CI Skip Instructions

---

[yjhjstz]

use github link

[zhangyue1818]

fix in 251adf4

[tuhaihe]

Need to use the standard ASF license header, e.g:

cloudberry/contrib/pgcrypto/sm3.h

Lines 1 to 26 in f61fbd9

	/*-------------------------------------------------------------------------
	*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*
	* sm3.h
	*
	* IDENTIFICATION
	* contrib/pgcrypto/sm3.h
	*
	*-------------------------------------------------------------------------
	*/

[tuhaihe]

It will be added for the original created files. For the third-party files, we need to keep the original license headers.

[zhangyue1818]

fix in 251adf4

[leborchuk]

Awesome! Could you please share some information about the architecture of the new solution? I think there might be an original (acmsigmod?) article on how to build an effective interconnect layer. (I see some familiar elements in the code, but I cannot fully comprehend what it is)

[zhangyue1818]

Awesome! Could you please share some information about the architecture of the new solution? I think there might be an original (acmsigmod?) article on how to build an effective interconnect layer. (I see some familiar elements in the code, but I cannot fully comprehend what it is)

During performance testing, we identified the Motion node as a significant performance bottleneck. Further analysis revealed that the root cause stems from inefficiencies in the underlying IPC layer protocol implementation. To address this, we plan to enhance the IPC layer to improve overall system performance.

Currently, the IPC layer is tightly coupled with the database kernel, which makes implementing performance optimizations challenging and limits flexibility. As an initial step, we are decoupling the IPC layer from the database kernel. This separation will not only simplify future improvements but also enable independent testing and development of the IPC layer.

This commit represents foundational work—specifically, the decoupling of the existing UDP-based IPC layer from the database kernel—and lays the groundwork for subsequent performance optimization efforts.

[tuhaihe]

The following two files also need the license header:

[WARNING] Files with unapproved licenses:
  contrib/udp2/CMakeLists.txt
  contrib/udp2/ic_common/CMakeLists.txt

[zhangyue1818]

7e7c028

The following two files also need the license header:

[WARNING] Files with unapproved licenses:
  contrib/udp2/CMakeLists.txt
  contrib/udp2/ic_common/CMakeLists.txt

fix in 251adf4