inIdexRangeScan for large table hit ERROR 9001 (HY000): PD server timeout due to "PD returned regions have gaps" #60627
Description
Bug Report
Please answer these questions before submitting your issue. Thanks!
1. Minimal reproduce step (Required)
One 1 billion rows table with one index.
Run the following sql
mysql> show create table t;
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| t | CREATE TABLE `t` (
`id` varchar(32) NOT NULL,
`k` bigint NOT NULL,
`c` varchar(32) DEFAULT NULL,
`b` decimal(19,3) DEFAULT NULL,
`r` datetime DEFAULT NULL,
`comments` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`) /*T![clustered_index] NONCLUSTERED */,
KEY `idx_k` (`k`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin /*T! SHARD_ROW_ID_BITS=4 PRE_SPLIT_REGIONS=4 */ |
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.05 sec)
run the following sql
mysql> select count(customer_number) from t_account where customer_number <> 'name10000001650000001';
ERROR 9001 (HY000): PD server timeout:
2. What did you expect to see? (Required)
mysql> select count(k) from t where k <> 'name10000001650000001';
+------------------------+
| count(k) |
+------------------------+
| 999999999 |
+------------------------+
1 row in set (2 min 40.31 sec)
3. What did you see instead (Required)
mysql> select count(k) from t where k <> 'name10000001650000001';
ERROR 9001 (HY000): PD server timeout:
error logs
2025-04-17 12:01:49 (UTC+08:00)TiDB tc-tidb-1.tc-tidb-peer.e2e-oltp-sysbench-wr-stab-tps-7754415-1-906.svc:4000[backoff.go:179] ["pdRPC backoffer.maxSleep 10000ms is exceeded, errors:\nPD returned regions have gaps, range num: 2, limit: 128 at 2025-04-17T12:01:44.521850053+08:00\nPD returned regions have gaps, range num: 2, limit: 128 at 2025-04-17T12:01:46.075557903+08:00\nPD returned regions have gaps, range num: 2, limit: 128 at 2025-04-17T12:01:47.738450713+08:00\ntotal-backoff-times: 8, backoff-detail: pdRPC:8, maxBackoffTimeExceeded: true, maxExcludedTimeExceeded: false\nlongest sleep type: pdRPC, time: 11932ms"] [conn=1646264616] [session_alias=]
4. What is your TiDB version? (Required)
v8.5.1