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Segfault-Inc / Multicorn

Data Access Library
https://multicorn.org/
PostgreSQL License
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Issue with PostgreSQL 9.6 and a Multicorn FDW #185

Closed elemoine closed 7 years ago

elemoine commented 7 years ago

I am facing a nasty bug that occurs when trying to read a ros bag file from within a Multicorn-based foreign table.

The bug results in a SIGSEGV in the libroslz4.so.1d library.

The same code works fine outside PostgreSQL/Multicorn. And the bug only triggers with PostgreSQL 9.6 (the FDW works fine in both PostgreSQL 9.4 and 9.5). This is why I am reaching out to the Multicorn community.

A full test-case with detailed instructions on how to reproduce the bug is available here: https://github.com/elemoine/FdwRosTest.

I am not sure this is an issue in Multicorn. But I am suspicious, given that the same code runs fine outside PostgreSQL or in PostgreSQL 9.4 or 9.5.

Note: this is with Python 2.7.

Thanks for any insight about the problem.

elemoine commented 7 years ago

Ok, the issue is related to symbol conflicts between liblz4 (which Postgres 9.6 uses) and libroslz4. And I now think the bug is on the roslz4 package (https://github.com/ros/ros_comm/pull/1065).

Sorry for the noise, Multicorn has nothing to do with that bug.