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executor: fix hash join between datetime and timestamp #25915

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merged 7 commits into from
Jul 6, 2021
Merged

executor: fix hash join between datetime and timestamp #25915

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30b99e9
fix 25902
sylzd Jul 4, 2021
0fd8cfd
fix annotation
sylzd Jul 4, 2021
1c48aef
add test case of datetime type
sylzd Jul 4, 2021
154565f
add test case of other timezone
sylzd Jul 5, 2021
ecfbd3f
fix UT
sylzd Jul 5, 2021
66fa1bd
fix UT session variable
sylzd Jul 5, 2021
dc4fc62
Merge branch 'master' into fix_25902
ti-chi-bot Jul 6, 2021
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17 changes: 17 additions & 0 deletions executor/join_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2592,3 +2592,20 @@ func (s *testSuiteJoinSerial) TestIssue20219(c *C) {
tk.MustQuery("select /*+ inl_join(s)*/ t.a from t left join s on t.a = s.a;").Check(testkit.Rows("i", "j"))
tk.MustQuery("show warnings").Check(testkit.Rows())
}

func (s *testSuiteJoinSerial) TestIssue25902(c *C) {
tk := testkit.NewTestKitWithInit(c, s.store)
tk.MustExec("drop table if exists tt1,tt2,tt3; ")
tk.MustExec("create table tt1 (ts timestamp);")
tk.MustExec("create table tt2 (ts varchar(32));")
tk.MustExec("create table tt3 (ts datetime);")
tk.MustExec("insert into tt1 values (\"2001-01-01 00:00:00\");")
tk.MustExec("insert into tt2 values (\"2001-01-01 00:00:00\");")
tk.MustExec("insert into tt3 values (\"2001-01-01 00:00:00\");")
tk.MustQuery("select * from tt1 where ts in (select ts from tt2);").Check(testkit.Rows("2001-01-01 00:00:00"))
tk.MustQuery("select * from tt1 where ts in (select ts from tt3);").Check(testkit.Rows("2001-01-01 00:00:00"))
tk.MustExec("set @tmp=(select @@session.time_zone);")
tk.MustExec("set @@session.time_zone = '+10:00';")
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Should we reset to time_zone to +08?

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thx, it fixed~

tk.MustQuery("select * from tt1 where ts in (select ts from tt2);").Check(testkit.Rows())
tk.MustExec("set @@session.time_zone = @tmp;")
}
18 changes: 2 additions & 16 deletions util/codec/codec.go
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Expand Up @@ -330,14 +330,7 @@ func encodeHashChunkRowIdx(sc *stmtctx.StatementContext, row chunk.Row, tp *type
case mysql.TypeDate, mysql.TypeDatetime, mysql.TypeTimestamp:
flag = uintFlag
t := row.GetTime(idx)
// Encoding timestamp need to consider timezone.
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I think here is right, the decoding process should take the timezone into consideration.

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Since we do not store the timezone information in the TiKV, all timestamp data is stored as UTC.
They are converted to UTC first, and then into a uint64

The read back process should convert the uint64 to the correct timestamp considering the timezone

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Timestamp hash table cannot be encoded by utc zone, because it's not a persistent table, and used by hash join. Is that used by any other places?

As I see, the hash table is not a persistent table, It's used to do join operator after being getted from kv and converted to the right timezone, other than store in kv.

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@sylzd sylzd Jul 5, 2021 •
edited
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For instance, this sql can produce the right result, because we do not convert timezone when do join. Timezone convertion should be considered when it was getted from kv.

select  /*+ MERGE_JOIN(tt1, tt2) */ * from tt1 inner join tt2 on tt1.ts=tt2.ts;

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Exactly

// If it's not in UTC, transform to UTC first.
if t.Type() == mysql.TypeTimestamp && sc.TimeZone != time.UTC {
err = t.ConvertTimeZone(sc.TimeZone, time.UTC)
if err != nil {
return
}
}

var v uint64
v, err = t.ToPackedUint()
if err != nil {
Expand Down Expand Up @@ -507,14 +500,7 @@ func HashChunkSelected(sc *stmtctx.StatementContext, h []hash.Hash64, chk *chunk
isNull[i] = !ignoreNull
} else {
buf[0] = uintFlag
// Encoding timestamp need to consider timezone.
// If it's not in UTC, transform to UTC first.
if t.Type() == mysql.TypeTimestamp && sc.TimeZone != time.UTC {
err = t.ConvertTimeZone(sc.TimeZone, time.UTC)
if err != nil {
return
}
}

var v uint64
v, err = t.ToPackedUint()
if err != nil {
Expand Down