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executor, planner: clone proj schema for different children in buildProj4Union #7999

Merged
merged 2 commits into from
Oct 23, 2018
Merged

executor, planner: clone proj schema for different children in buildProj4Union #7999

merged 2 commits into from
Oct 23, 2018

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XuHuaiyu
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What problem does this PR solve? 

create table t(a int, b int);
insert into t values(1,2);
select a, b from (select a, 0 as d, b from t union all select a, 0 as d, b from t) test;

we want:

+------+------+
| a    | b    |
+------+------+
|    1 |    2 |
|    1 |    2 |
+------+------+

but got:

+------+------+
| a    | b    |
+------+------+
|    1 |    0 |
|    1 |    2 |
+------+------+

What is changed and how it works?

Clone the schema for different projections which are built in buildProjection4Union.

Before this commit, Schema.Columns of different LogicalProjections which are built upon the children of Union refer to the same Column slice.

The Schema.Columns is [test.a, d, test.b] in the above example.
After calling Union.Children[0].PruneColumn, we use this to prune the columns.
Thus Union.Children[1].schema.Columns will become [test.a, test.b, test.b].
Furthermore, used bool slice will become [true, true, false], and cause test.b be pruned wrongly.

Check List

Tests

  • Integration test

Code changes

  • Has exported function/method change

Side effects

none

Related changes

  • Need to cherry-pick to the release branch

@XuHuaiyu XuHuaiyu added type/bugfix This PR fixes a bug. sig/planner SIG: Planner labels Oct 23, 2018
@XuHuaiyu
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/run-all-tests

zz-jason
zz-jason reviewed Oct 23, 2018
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LGTM

@zz-jason zz-jason added the status/LGT1 Indicates that a PR has LGTM 1. label Oct 23, 2018
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should be cherry-picked to release-2.1 and release-2.0?

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@kennytm @winoros PTAL

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I'll cherry-pick the commit after this PR be merged.

@XuHuaiyu XuHuaiyu added the priority/P1 The issue has P1 priority. label Oct 23, 2018
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winoros commented Oct 23, 2018 •
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Emmm... You mean the columns that share the same unique id may cause bug if they share the same memory address?
Okay i got it. They share the same slice header.

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Not quite but almost. @winoros

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winoros commented Oct 23, 2018

Actually we just need to use a new slice header, don't need to clone the columns.
But whatever this can lgtm.

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A new slice header cannot solve the problem,
since we changed the original data of the slice.

winoros
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lgtm

@XuHuaiyu XuHuaiyu added status/LGT2 Indicates that a PR has LGTM 2. and removed status/LGT1 Indicates that a PR has LGTM 1. labels Oct 23, 2018
@XuHuaiyu XuHuaiyu merged commit 76f84f4 into pingcap:master Oct 23, 2018
@XuHuaiyu XuHuaiyu deleted the union_proj branch October 23, 2018 05:34
XuHuaiyu added a commit to XuHuaiyu/tidb that referenced this pull request Oct 23, 2018
@XuHuaiyu
executor, planner: clone proj schema for different children in buildP…
61c57b7 
…roj4Union (pingcap#7999)
@XuHuaiyu XuHuaiyu mentioned this pull request Oct 23, 2018
Merged
zz-jason pushed a commit that referenced this pull request Oct 23, 2018
@XuHuaiyu @zz-jason
executor, planner: clone proj schema for different children in buildP…
4741e6b 
…roj4Union (#7999) (#8007)
iamzhoug37 pushed a commit to iamzhoug37/tidb that referenced this pull request Oct 25, 2018
@iamzhoug37
fix issue 7518
f15bb5c 
bugfix fixed pingcap#7518

expression: MySQL compatible current_user function (pingcap#7801)

plan: propagate constant over outer join (pingcap#7794)

- extract `outerCol = const` from join conditions and filter conditions,
  substitute `outerCol` in join conditions with `const`;
- extract `outerCol = innerCol` from join conditions, derive new join
  conditions based on this column equal condition and `outerCol` related
  expressions in join conditions and filter conditions;

util/timeutil: fix data race caused by forgetting set stats lease to 0 (pingcap#7901)

stats: handle ddl event for partition table (pingcap#7903)

plan: implement Operand and Pattern of cascades planner. (pingcap#7910)

planner: not convert to TableDual if empty range is derived from deferred constants (pingcap#7808)

plan: move projEliminate behind aggEliminate (pingcap#7909)

admin: fix admin check table bug of byte compare (pingcap#7887)

* admin: remove reflect deepEqual

stats: fix panic caused by empty histogram (pingcap#7912)

plan: fix panic caused by empty schema of LogicalTableDual (pingcap#7906)

* fix drop view if exist error (pingcap#7833)

executor: refine `explain analyze` (pingcap#7888)

executor: add an variable to compatible with MySQL insert for OGG (pingcap#7863)

expression: maintain `DeferredExpr` in aggressive constant folding. (pingcap#7915)

stats: fix histogram boundaries overflow error (pingcap#7883)

ddl:support the definition of `null` change to `not null` using `alter table` (pingcap#7771)

* ddl:support the definition of null change to not null using alter table

ddl: add check when create table with foreign key. (pingcap#7885)

* ddl: add check when create table with foreign key

planner: eliminate if null on non null column (pingcap#7924)

executor: fix a bug in point get (pingcap#7934)

planner, executor: refine ColumnPrune for LogicalUnionAll (pingcap#7930)

executor: fix panic when limit is too large (pingcap#7936)

ddl: add TiDB version to metrics (pingcap#7902)

stats: limit the length of sample values (pingcap#7931)

vendor: update tipb (pingcap#7893)

planner: support the Group and GroupExpr for the cascades planner (pingcap#7917)

store/tikv: log more information when other err occurs (pingcap#7948)

types: fix date time parse (pingcap#7933)

ddl: just print error message when ddl job is normal to calcel, to eliminate noisy log (pingcap#7875)

stats: update delta info for partition table (pingcap#7947)

explaintest: add explain test for partition pruning (pingcap#7505)

util: move disjoint set to util package (pingcap#7950)

util: add PreAlloc4Row and Insert for Chunk and List (pingcap#7916)

executor: add the slow log for commit (pingcap#7951)

expression: add builtin json_keys (pingcap#7776)

privilege: add USAGE in `show grants` for mysql compatibility (pingcap#7955)

ddl: fix invailid ddl job panic (pingcap#7940)

*: move ast.NewValueExpr to standalone parser_driver package (pingcap#7952)

Make the ast package get rid of the dependency of types.Datum

server: allow cors http request (pingcap#7939)

*: move `Statement` and `RecordSet` from ast to sqlexec package (pingcap#7970)

pr suggestion update

executor/aggfuncs: split unit tests to corresponding file (pingcap#7993)

store/tikv: fix typo (pingcap#7990)

executor, planner: clone proj schema for different children in buildProj4Union (pingcap#7999)

executor: let information_schema be the first database in ShowDatabases (pingcap#7938)

stats: use local feedback for partition table (pingcap#7963)

executor: add unit test for aggfuncs (pingcap#7966)

server: add log for binary execute statement (pingcap#7987)

admin: refine admin check decoder (pingcap#7862)

executor: improve wide table insert & update performance (pingcap#7935)

ddl: fix reassigned partition id in `truncate table` does not take effect (pingcap#7919)

fix reassigned partition id in truncate table does not take effect

add changelog for 2.1.0 rc4 (pingcap#8020)

*: make parser package dependency as small as possible (pingcap#7989)

parser: support `:=` in the `set` syntax (pingcap#8018)

According to MySQL document, `set` use the = assignment operator,
but the := assignment operator is also permitted

stats: garbage collect stats for partition table (pingcap#7962)

docs: add the proposal for the column pool (pingcap#7988)

expression: refine built-in func truncate to support uint arg (pingcap#8000)

stats: support show stats for partition table (pingcap#8023)

stats: update error rate for partition table (pingcap#8022)

stats: fix estimation for out of range point queries (pingcap#8015)

*: move parser to a separate repository (pingcap#8036)

executor: fix wrong result when index join on union scan. (pingcap#8031)

Do not modify Plan of dataReaderBuilder directly, because it would
impact next batch of outer rows, as well as other concurrent inner
workers. Instead, build a local child builder to store the child plan.

planner: fix a panic of a cached prepared statement with IndexScan (pingcap#8017)

*: fix the issue of executing DDL after executing SQL failure in txn (pingcap#8044)

* ddl, executor: fix the issue of executing DDL after executing SQL failure in txn

add unit test

remove debug info

add like evaluator case sensitive test

ddl, domain: make schema correct after canceling jobs (pingcap#7997)

unit test fix

code format

proposal: maintaining histograms in plan. (pingcap#7605)

support _tidb_rowid for table scan range (pingcap#8047)

var rename fix
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