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e987b9350c
(Review input addressed)
(Added handling of UPDATE/DELETE and partitioning w/o index)
If the properties of the used collation allow, do the following
equivalent rewrites:
1. UPPER(key_col)=expr -> key_col=expr
expr=UPPER(key_col) -> expr=key_col
(also rewrite both sides of the equality at the same time)
2. UPPER(key_col) IN (constant-list) -> key_col IN (constant-list)
- Mark utf8mb{3,4}_general_ci as collations that allow this.
- Add optimizer_switch='sargable_casefold=ON' to control this.
(ON by default in this patch)
- Cover the rewrite in Optimizer Trace, rewrite name is
"sargable_casefold_removal".
58 lines
1.2 KiB
Text
58 lines
1.2 KiB
Text
set
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@tmp_switch_sarg_casefold=@@optimizer_switch,
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optimizer_switch='sargable_casefold=on';
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create table t1 (
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s1 varchar(15) collate utf8mb3_bin,
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s2 varchar(15) collate utf8mb3_general_ci
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) partition by key (s2) partitions 4;
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insert into t1 values ('aa','aa'),('bb','bb');
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explain format=json select * from t1 where upper(s2)='AA';
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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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"nested_loop": [
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{
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"table": {
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"table_name": "t1",
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"partitions": ["p2"],
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"access_type": "system",
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"rows": 1,
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"filtered": 100
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}
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}
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]
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}
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}
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explain format=json delete from t1 where upper(s2)='AA';
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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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"delete": 1,
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"table_name": "t1",
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"partitions": ["p2"],
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"access_type": "ALL",
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"rows": 1,
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"attached_condition": "t1.s2 = 'AA'"
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}
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}
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}
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explain format=json update t1 set s1='aaa' where upper(s2)='AA';
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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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"update": 1,
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"table_name": "t1",
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"partitions": ["p2"],
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"access_type": "ALL",
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"rows": 1,
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"attached_condition": "t1.s2 = 'AA'"
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}
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}
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}
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drop table t1;
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set optimizer_switch=@tmp_switch_sarg_casefold;
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