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MDEV-8829: Assertion `0' failed in Explain_table_access::tag_to_json
- Add EXPLAIN/ANALYZE FORMAT=JSON handling for a few special cases.
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‎mysql-test/r/explain_json.result‎

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@@ -1194,3 +1194,352 @@ EXPLAIN
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}
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}
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drop table t0, t1, t2;
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#
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# MDEV-8829: Assertion `0' failed in Explain_table_access::tag_to_json
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#
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# Check ET_CONST_ROW_NOT_FOUND
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create table t1 (i int) engine=myisam;
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explain
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select * from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 0 const row not found
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explain format=json
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select * from t1;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"table": {
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"table_name": "t1",
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"access_type": "system",
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"rows": 0,
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"filtered": 0,
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"const_row_not_found": true
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}
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}
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}
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analyze format=json
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select * from t1;
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ANALYZE
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{
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"query_block": {
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"select_id": 1,
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"table": {
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"message": "no matching row in const table"
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}
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}
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}
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drop table t1;
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# Check ET_IMPOSSIBLE_ON_CONDITION
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create table t1 (a int);
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create table t2 (pk int primary key);
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insert into t1 values (1),(2);
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insert into t2 values (1),(2);
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explain
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select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 const PRIMARY NULL NULL NULL 1 Impossible ON condition
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2
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explain format=json
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select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"const_condition": "1",
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"table": {
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"table_name": "t2",
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"access_type": "const",
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"possible_keys": ["PRIMARY"],
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"rows": 1,
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"filtered": 100,
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"impossible_on_condition": true
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},
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"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"rows": 2,
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"filtered": 100
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}
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}
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}
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analyze format=json
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select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
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ANALYZE
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{
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"query_block": {
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"select_id": 1,
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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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"table": {
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"table_name": "t2",
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"access_type": "const",
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"possible_keys": ["PRIMARY"],
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"r_loops": 0,
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"rows": 1,
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"r_rows": null,
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"filtered": 100,
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"r_filtered": null,
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"impossible_on_condition": true
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},
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"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 2,
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"r_rows": 2,
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"r_total_time_ms": "REPLACED",
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"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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# Check ET_NOT_EXISTS:
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explain
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select * from t1 left join t2 on t2.pk=t1.a where t2.pk is null;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2
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1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using where; Using index; Not exists
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explain format=json
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select * from t1 left join t2 on t2.pk=t1.a where t2.pk is null;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"rows": 2,
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"filtered": 100
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},
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"table": {
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"table_name": "t2",
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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": ["pk"],
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"ref": ["test.t1.a"],
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"rows": 1,
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"filtered": 100,
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"attached_condition": "(trigcond(isnull(t2.pk)) and trigcond(trigcond((t1.a is not null))))",
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"using_index": true,
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"not_exists": true
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}
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}
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}
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analyze format=json
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select * from t1 left join t2 on t2.pk=t1.a where t2.pk is null;
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ANALYZE
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{
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"query_block": {
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"select_id": 1,
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 2,
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"r_rows": 2,
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"r_total_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": 100
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},
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"table": {
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"table_name": "t2",
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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": ["pk"],
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"ref": ["test.t1.a"],
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"r_loops": 2,
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"rows": 1,
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"r_rows": 1,
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"r_total_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": 100,
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"attached_condition": "(trigcond(isnull(t2.pk)) and trigcond(trigcond((t1.a is not null))))",
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"using_index": true,
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"not_exists": true
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}
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}
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}
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# Check ET_DISTINCT
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explain
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select distinct t1.a from t1 join t2 on t2.pk=t1.a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2 Using where; Using temporary
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1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using index; Distinct
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explain format=json
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select distinct t1.a from t1 join t2 on t2.pk=t1.a;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"temporary_table": {
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"function": "buffer",
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"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"rows": 2,
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"filtered": 100,
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"attached_condition": "(t1.a is not null)"
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},
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"table": {
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"table_name": "t2",
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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": ["pk"],
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"ref": ["test.t1.a"],
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"rows": 1,
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"filtered": 100,
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"using_index": true,
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"distinct": true
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}
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}
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}
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}
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analyze format=json
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select distinct t1.a from t1 join t2 on t2.pk=t1.a;
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ANALYZE
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{
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"query_block": {
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"select_id": 1,
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"temporary_table": {
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"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 2,
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"r_rows": 2,
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"r_total_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": 100,
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"attached_condition": "(t1.a is not null)"
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},
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"table": {
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"table_name": "t2",
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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": ["pk"],
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"ref": ["test.t1.a"],
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"r_loops": 2,
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"rows": 1,
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"r_rows": 1,
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"r_total_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": 100,
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"using_index": true,
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"distinct": true
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}
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}
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}
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}
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drop table t1,t2;
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# Check ET_USING_INDEX_CONDITION_BKA
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create table t1(a int);
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insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
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create table t2(a int);
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insert into t2 select A.a + B.a* 10 + C.a * 100 from t1 A, t1 B, t1 C;
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create table t3(a int, b int);
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insert into t3 select a,a from t1;
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create table t4(a int, b int, c int, filler char(100), key (a,b));
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insert into t4 select a,a,a, 'filler-data' from t2;
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set @tmp_optimizer_switch=@@optimizer_switch;
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set @tmp_join_cache_level=@@join_cache_level;
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set optimizer_switch='mrr=on';
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set join_cache_level=6;
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explain
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select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t3 ALL NULL NULL NULL NULL 10 Using where
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1 SIMPLE t4 ref a a 5 test.t3.a 1 Using index condition(BKA); Using join buffer (flat, BKA join); Rowid-ordered scan
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explain format=json
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select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"table": {
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"table_name": "t3",
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"access_type": "ALL",
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"rows": 10,
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"filtered": 100,
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"attached_condition": "(t3.a is not null)"
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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": "ref",
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"possible_keys": ["a"],
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"key": "a",
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"key_length": "5",
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"used_key_parts": ["a"],
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"ref": ["test.t3.a"],
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"rows": 1,
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"filtered": 100,
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"index_condition_bka": "((t4.b + 1) <= (t3.b + 1))"
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},
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"buffer_type": "flat",
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"buffer_size": "256Kb",
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"join_type": "BKA",
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"mrr_type": "; Rowid-ordered scan"
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}
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}
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}
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analyze format=json
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select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
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ANALYZE
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{
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"query_block": {
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"select_id": 1,
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"r_loops": 1,
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"r_total_time_ms": "REPLACED",
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"table": {
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"table_name": "t3",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 10,
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"r_rows": 10,
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"r_total_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": 100,
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"attached_condition": "(t3.a is not null)"
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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": "ref",
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"possible_keys": ["a"],
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"key": "a",
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"key_length": "5",
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"used_key_parts": ["a"],
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"ref": ["test.t3.a"],
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"r_loops": 0,
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"rows": 1,
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"r_rows": null,
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"r_total_time_ms": "REPLACED",
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"filtered": 100,
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"r_filtered": null,
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"index_condition_bka": "((t4.b + 1) <= (t3.b + 1))"
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},
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"buffer_type": "flat",
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"buffer_size": "256Kb",
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"join_type": "BKA",
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"mrr_type": "; Rowid-ordered scan",
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"r_filtered": 100
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}
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}
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}
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set optimizer_switch=@tmp_optimizer_switch;
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set join_cache_level=@tmp_join_cache_level;
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drop table t1,t2,t3,t4;

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