Thread

1. Failing assertion in predicate.c

   Yurii Rashkovskii <yrashk@omnigres.com> — 2024-10-16T17:28:59Z

   Hi pg-hackers,
   
   I am encountering an assertion failure in predicate.c when running a high
   volume of short serializable transactions. The error occurs during stress
   testing with many concurrent connections.
   
   I have replicated this issue on two separate macOS M1 systems, but I have
   not been able to reproduce it on Linux. The issue arises in both PostgreSQL
   16 and 17. Interestingly, introducing a delay of just 1 ms between
   statements seems to prevent the assertion from failing.
   
   The specific failure I encounter is:
   
   ```
   TRAP: failed Assert("TransactionIdIsValid(tailXid)"), File: "predicate.c",
   Line: 885, PID: 1350
   ```
   
   For anyone interested, I have created a reproduction program available
   here: https://github.com/yrashk/pg-predicate-tailxid-assertion-issue. The
   program establishes a connection pool and issues simple INSERT statements,
   each wrapped in its own serializable transaction.
   
   I would appreciate any insights into this issue or potential steps for
   further debugging.
   
   
   -- 
   Founder at Omnigres
   https://omnigres.com
   

2. Re: Failing assertion in predicate.c

   Andrew Bille <andrewbille@gmail.com> — 2024-10-17T05:50:12Z

   Hi, Yurii!
   
   Please look at the bug report, I filed yesterday almost simultaneously with
   you:
   https://www.postgresql.org/message-id/18658-7dab125ec688c70b%40postgresql.org
   
   Thanks!
   
   On Thu, Oct 17, 2024 at 12:49 PM Yurii Rashkovskii <yrashk@omnigres.com>
   wrote:
   
   > Hi pg-hackers,
   >
   > I am encountering an assertion failure in predicate.c when running a high
   > volume of short serializable transactions. The error occurs during stress
   > testing with many concurrent connections.
   >
   > I have replicated this issue on two separate macOS M1 systems, but I have
   > not been able to reproduce it on Linux. The issue arises in both PostgreSQL
   > 16 and 17. Interestingly, introducing a delay of just 1 ms between
   > statements seems to prevent the assertion from failing.
   >
   > The specific failure I encounter is:
   >
   > ```
   > TRAP: failed Assert("TransactionIdIsValid(tailXid)"), File: "predicate.c",
   > Line: 885, PID: 1350
   > ```
   >
   > For anyone interested, I have created a reproduction program available
   > here: https://github.com/yrashk/pg-predicate-tailxid-assertion-issue. The
   > program establishes a connection pool and issues simple INSERT statements,
   > each wrapped in its own serializable transaction.
   >
   > I would appreciate any insights into this issue or potential steps for
   > further debugging.
   >
   >
   > --
   > Founder at Omnigres
   > https://omnigres.com
   >
   >