Fix segmentation fault in pylibseekdb when executing dbms_vector.refresh_index/rebuild_index SQL

Environment

• pylibseekdb Version: 2026.5.12.dev1
• pyseekdb Version: 1.2.0.post2
• Python Version: 3.11
• Is this an RD-provided temporary version? No

Description

When executing SQL related to dbms_vector.refresh_index or dbms_vector.rebuild_index in the test case test_cases/vector_function_mysql_sqlqa/test_refresh_index_mysql.py::TestVectorRefresh::test_vector_refresh_functionality, the process encounters a Segmentation fault.

Steps to Reproduce

1. Activate the virtual environment: /data/1/liteembeddedtest/LiteEmbeddedTest/myenv_work
2. Run the minimal reproduction command:

   python3.11 -X faulthandler -m pytest test_cases/vector_function_mysql_sqlqa/test_refresh_index_mysql.py::TestVectorRefresh::test_vector_refresh_functionality -v -s
   

Note: The issue can also be reproduced by running the Jenkins job at http://:9090/jenkins/job/wentian_test/208/.

Additional Context

• Reproducibility: Consistently reproducible (必现).
• Machine: work 398tF0wqByZeQki5
• Core File: /data/1/core-python3.11-1884164-1778601004
• GDB Backtrace: /data/1/gdb-bt-core-python3.11-1884164-1778601004.txt
• Related Issue: This may be related to the issue "【Lite】嵌入式,pyseekdb [embedded]，fork collection和更新索引都报超时，之前可行" (Embedded pyseekdb reports timeouts on fork collection and index updates, previously worked).

Logs & Diagnostics

• The process previously terminated with a Segmentation fault.
• Core dump and GDB backtrace files are available at the paths listed above.

Run test_cases/vector_function_mysql_sqlqa/test_refresh_index_mysql.py::TestVectorRefresh::test_vector_refresh_functionality with the provided Python command to reproduce the fault. Start by examining the listed core file and GDB backtrace, then trace the dbms_vector.refresh_index and rebuild_index execution paths. Done means the test completes without a segmentation fault.