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0940a96940
Part#2, variant 2: Make the printed r_ values in JSON output consistent. After this patch, ANALYZE output has: - r_index_rows (NEW) - Observed number of rows before ICP or Rowid Filtering checks. This is a per-scan average. like r_rows and "rows" are. - r_rows (AS BEFORE) - Observed number of rows after ICP and Rowid Filtering. - r_icp_filtered (NEW) - Observed selectivity of ICP condition. - (AS BEFORE) observed selectivity of Rowid Filter is in $.rowid_filter.r_selectivity_pct - r_total_filtered - Observed combined selectivity: fraction of rows left after applying ICP condition, Rowid Filter, and attached_condition. This is now comparable with "filtered" and is printed right after it. - r_filtered (AS BEFORE) - Observed selectivity of "attached_condition". Tabular ANALYZE output is not changed. Note that JSON's r_filtered and r_rows have the same meanings as before and have the same meaning as in tabular output.
131 lines
3.8 KiB
Text
131 lines
3.8 KiB
Text
#
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# MDEV-32351: Significant slowdown for query with many outer joins
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#
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CREATE TABLE t1 (b int NOT NULL, PRIMARY KEY (b)) ENGINE=MYISAM;
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INSERT INTO t1 select seq from seq_1_to_10000;
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CREATE TABLE t2 (b int NOT NULL, d varchar(255), KEY (b)) ENGINE=MYISAM ;
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INSERT INTO t2 VALUES (1,1),(2,2),(3,3);
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CREATE TABLE t3 (c int NOT NULL, PRIMARY KEY (c)) ENGINE=MYISAM ;
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INSERT INTO t3 select seq from seq_1_to_3000;
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CREATE TABLE t4 (c int NOT NULL, PRIMARY KEY (c)) ENGINE=MYISAM;
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INSERT INTO t4 select seq from seq_1_to_3000;
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ANALYZE TABLE t1,t2,t3,t4;
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Table Op Msg_type Msg_text
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test.t1 analyze status Engine-independent statistics collected
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test.t1 analyze status OK
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test.t2 analyze status Engine-independent statistics collected
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test.t2 analyze status OK
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test.t3 analyze status Engine-independent statistics collected
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test.t3 analyze status OK
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test.t4 analyze status Engine-independent statistics collected
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test.t4 analyze status OK
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create table t1_t2 as
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select
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t1.b as t1_b, t2.b as t2_b, t2.d as t2_d
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FROM t1
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LEFT JOIN t2 ON t1.b = t2.b;
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SET statement debug_dbug='+d,analyze_print_r_unpack_ops' for
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analyze
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format=json
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SELECT COUNT(*)
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FROM t1_t2
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LEFT JOIN t3 ON t2_d = t3.c
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LEFT JOIN t4 ON t3.c=1
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select '$js' as JSON;
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JSON
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{
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"query_optimization": {
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"r_total_time_ms": "REPLACED"
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},
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"query_block": {
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"select_id": 1,
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"cost": "REPLACED",
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"const_condition": "1",
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"nested_loop": [
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{
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"table": {
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"table_name": "t1_t2",
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"access_type": "ALL",
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"loops": 1,
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"r_loops": 1,
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"rows": 10000,
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"r_rows": 10000,
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"cost": "REPLACED",
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"r_table_time_ms": "REPLACED",
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"r_other_time_ms": "REPLACED",
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"r_engine_stats": REPLACED,
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"filtered": 100,
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"r_total_filtered": 100,
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"r_filtered": 100
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}
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},
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{
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"table": {
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"table_name": "t3",
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"access_type": "eq_ref",
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"possible_keys": ["PRIMARY"],
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"key": "PRIMARY",
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"key_length": "4",
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"used_key_parts": ["c"],
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"ref": ["test.t1_t2.t2_d"],
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"loops": 10000,
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"r_loops": 10000,
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"r_table_loops": 3,
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"rows": 1,
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"r_rows": 0.0003,
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"cost": "REPLACED",
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"r_table_time_ms": "REPLACED",
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"r_other_time_ms": "REPLACED",
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"r_engine_stats": REPLACED,
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"filtered": 100,
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"r_total_filtered": 100,
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"attached_condition": "trigcond(t1_t2.t2_d = t3.c and trigcond(t1_t2.t2_d is not null))",
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"r_filtered": 100,
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"using_index": true
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}
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},
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{
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"block-nl-join": {
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"table": {
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"table_name": "t4",
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"access_type": "index",
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"key": "PRIMARY",
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"key_length": "4",
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"used_key_parts": ["c"],
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"loops": 10000,
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"r_loops": 1,
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"rows": 3000,
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"r_rows": 3000,
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"cost": "REPLACED",
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"r_table_time_ms": "REPLACED",
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"r_other_time_ms": "REPLACED",
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"r_engine_stats": REPLACED,
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"filtered": 100,
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"r_total_filtered": 100,
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"r_filtered": 100,
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"using_index": true
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},
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"buffer_type": "flat",
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"buffer_size": "256Kb",
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"join_type": "BNL",
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"attached_condition": "trigcond(trigcond(t3.c = 1))",
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"r_loops": 10000,
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"r_filtered": 0.04333,
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"r_unpack_time_ms": "REPLACED",
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"r_unpack_ops": 3000,
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"r_other_time_ms": "REPLACED",
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"r_effective_rows": 3000
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}
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}
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]
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}
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}
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# This must show 3000, not 30000000:
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select json_extract('$js', '\$**.r_unpack_ops') as R_UNPACK_OPS;
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R_UNPACK_OPS
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[3000]
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SET debug_dbug=@old_debug;
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drop table t1,t2,t3,t4;
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drop table t1_t2;
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