OceanBase 数据库集群内简单 SQL 语句因 -6004(lock_for_read need retry) 变慢的原因和解决方法

[2024-08-21 18:55:38.847056] WDIAG [STORAGE.TRANS] ob_memtable_context.cpp:409 [33428][0][xxxx-xxxx-xxxx-xxxx] [lt=8] [dc=0][errcode=-6004] lock_for_read need retry(ret=-6004, *this=alloc_type=0 ctx_descriptor=0 min_table_version=0 max_table_version=1723222694410248 is_safe_read=false read_snapshot=1724237737939741 start_version=-1 trans_version=9223372036854775807 commit_version=0 stmt_start_time=1724237737950097 abs_expired_time=1724241337880131 stmt_timeout=3599930034 abs_lock_wait_timeout=0 row_purge_version=0 lock_wait_start_ts=0 trx_lock_timeout=-1 end_code=0 is_readonly=true ref=0 pkey= trans_id= trans_mem_total_size=0 checksum_log_ts=0, *mem_ctx=alloc_type=0 ctx_descriptor=112552661 min_table_version=1708704838476680 max_table_version=1708704838476680 is_safe_read=false read_snapshot=1724237721811583 start_version=-1 trans_version=1724237737148950 commit_version=0 stmt_start_time=1724237721811009 abs_expired_time=1724241321711500 stmt_timeout=3599900491 abs_lock_wait_timeout=1724241321711500 row_purge_version=0 lock_wait_start_ts=0 trx_lock_timeout=-1 end_code=0 is_readonly=false ref=0 pkey={tid:1100611139455225, partition_id:0, part_cnt:0} trans_id={hash:12218919584240162027, inc:5894164303, addr:"10.20.140.22:2882", t:1724237700192074} trans_mem_total_size=47631815 checksum_log_ts=0, version=1724237737939741)