[YSQL] Dont COMMIT after an ERROR in COPY

Description

WARNING:  Batched COPY is not supported in transaction blocks. Defaulting to using one transaction for the entire copy.
HINT:  Either run this COPY outside of a transaction block or set rows_per_transaction option to `0` to disable batching and remove this warning.
CONTEXT:  SQL statement "COPY shell_output FROM PROGRAM
ERROR:  Commit of transaction that requires restart is not allowed
STATEMENT:  COMMIT;

Contributor guide

Tech stack

sqlpostgresql

Domain

databasebackend

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

4

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

3-5 days

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

fresh

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

SQLPostgreSQL internalsTransaction handling

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

20

Research direction

Investigate the COPY implementation in YSQL, focusing on how transactions are handled during a batched COPY. Look at files like `src/postgres/src/backend/commands/copy.c` and YB specific wrapper code. The issue shows a warning about batched COPY not supported in transaction blocks, and then an error on COMMIT. Need to understand why COMMIT is issued after an error and how to prevent it. Check linked Jira issue for additional context.