问题相似：order by asc 和desc 响应时差不一
集群版本：5.0.4
PS：表统计信息每天收集
gc-life-time =8h
- ASC 慢 sql：
# Time: 2022-07-06T09:23:30.70220307+08:00
# Txn_start_ts: 434390759282835474
# Conn_ID: 23472111
# Query_time: 1369.013604921
# Parse_time: 0.000064954
# Compile_time: 0.00041523
# Rewrite_time: 0.000100666
# Optimize_time: 0.000189457
# Wait_TS: 0.000027597
# Cop_time: 1368.741306837 Process_time: 1335.475 Wait_time: 5.12 Backoff_time: 15.19 Request_count: 13762 Process_keys: 100 Total_keys: 5186334980 Rocksdb_delete_skipped_count: 3847527 Rocksdb_key_skipped_count: 5193472877 Rocksdb_block_cache_hit_count: 128933 Rocksdb_block_read_count: 3433538 Rocksdb_block_read_byte: 15552386931
# Is_internal: false
# Digest: 00dce6df80ad19fbbc855e012f29395af002befab0ad17055ddbcd2212dbdd32
# Stats: t1:434382294313336944
# Num_cop_tasks: 13762
# Cop_proc_avg: 0.097040764 Cop_proc_p90: 0.158 Cop_proc_max: 0.458 Cop_proc_addr: ip1:20160
# Cop_wait_avg: 0.000372038 Cop_wait_p90: 0.001 Cop_wait_max: 0.011 Cop_wait_addr: ip2:20160
# Cop_backoff_regionMiss_total_times: 7595 Cop_backoff_regionMiss_total_time: 15.19 Cop_backoff_regionMiss_max_time: 0.002 Cop_backoff_regionMiss_max_addr: 172.16.25.8:20160 Cop_backoff_regionMiss_avg_time: 0.002 Cop_backoff_regionMiss_p90_time: 0.002
# Mem_max: 11874
# Prepared: false
# Plan_from_cache: false
# Plan_from_binding: false
# Has_more_results: false
# KV_total: 1348.78450469
# PD_total: 2.6595965010000002
# Backoff_total: 15.194
# Write_sql_response_total: 0.000011118
# Succ: true
# Plan_digest: d615ddde2dbc83573fa182d7fbe85507a864959c9472780b366cb033d06141b8
SELECT xxxxx_ID FROM t1 ORDER BY I_ID ASC LIMIT 100;
- DESC 慢SQL
# Time: 2022-07-06T20:05:24.196223074+08:00
# Txn_start_ts: 434401213205446729
# Conn_ID: 24416521
# Query_time: 3.969983584
# Parse_time: 0.000049059
# Compile_time: 0.000247488
# Rewrite_time: 0.00004905
# Optimize_time: 0.00012623
# Wait_TS: 0.000012632
# Cop_time: 0.001093352 Request_count: 2 Process_keys: 100 Total_keys: 108 Rocksdb_delete_skipped_count: 20 Rocksdb_key_skipped_count: 147 Rocksdb_block_cache_hit_count: 27 Rocksdb_block_read_count: 4 Rocksdb_block_read_byte: 69750
# Is_internal: false
# Digest: 1b6ec0b90d04550a4a5fa1952e8a57c6460ad7a19aa51fc5718d1b161496fc5c
# Stats: t1:434398306067808282
# Num_cop_tasks: 2
# Cop_proc_avg: 0 Cop_proc_p90: 0 Cop_proc_max: 0 Cop_proc_addr: ip1:20160
# Cop_wait_avg: 0 Cop_wait_p90: 0 Cop_wait_max: 0 Cop_wait_addr: ip2:20160
# Mem_max: 11688
# Prepared: false
# Plan_from_cache: false
# Plan_from_binding: false
# Has_more_results: false
# KV_total: 0.002458376
# PD_total: 3.717066355
# Backoff_total: 0
# Write_sql_response_total: 0.000010702
# Succ: true
SELECT xxx_ID FROM t1 ORDER BY I_ID desc LIMIT 100;
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