BUG #19103: Canceled INSERT statement can still influence the performance of subsequent SELECT statement

The following bug has been logged on the website:

Bug reference: 19103
Logged by: Jinhui Lai
Email address: jinhui(dot)lai(at)qq(dot)com
PostgreSQL version: 18.0
Operating system: ubuntu 22.04
Description:

Dear PG developers:

Thanks for reading my report. Here, I find a performance issue. I have
found a performance issue where a canceled INSERT statement appears to
negatively impact the performance of subsequent SELECT queries.

Steps to Reproduce:

\timing on
CREATE TABLE t0(c0 INT8);
INSERT INTO t1 VALUES(1);
CREATE TABLE t1(c1 INT8);
INSERT INTO t1 SELECT * FROM generate_series(1, 100000000);
^CCancel request sent
ERROR: canceling statement due to user request
Time: 50685.063 ms (00:50.685)

SELECT COUNT(*) FROM t0;
count
-------
0
(1 row)
Time: 1.264 ms

SELECT COUNT(*) FROM t1;
count
-------
0
(1 row)
Time: 3466.933 ms (00:03.467)

This performance degradation could affect systems where large batch
operations are frequently started and canceled, potentially impacting
overall database responsiveness.

Thank you for investigating this issue.

Best regards,
Jinhui Lai