dm: tracker panic when pk of downstream table orders behind

[D3Hunter]

What did you do?

to reproduce

• downstream create table before sync or the table has no pk on create then add multiple pk later.
• tracker will panic when downstream table ddl has, but even if the ddl doesn't satisfy all condition, dm may use the wrong key:
  • multiple normal index before pk
  • multiple uk/pk
  • number of normal index >= number of uk/pk

such as downstream create table below before sync:

create table t(
    a int not null,
    b int not null,
    c int not null,
    d int not null,
    e int not null,
    index (a),
    index(b),
    index(c),
    unique(d),
    unique(e)
);

or add pk after create table in upstream:

create database test;
use test;
create table t(
    a int not null,
    b int not null,
    c int not null,
    d int not null,
    e int not null,
    index (a),
    index(b),
    index(c)
);

alter table t add unique(d);
alter table t add unique(e);
show create table t;
insert into t values(1,1,1,1,1);

code panics since absoluteUKPosition comes from all indices but index into uk/pk arr:

tiflow/dm/pkg/schema/tracker.go

Line 569 in 2605a84

availableUKIndexList[0], availableUKIndexList[absoluteUKPosition] = availableUKIndexList[absoluteUKPosition], availableUKIndexList[0]

"Message": "panic error: runtime error: index out of range [3] with length 2",

What did you expect to see?

works

What did you see instead?

panic

Versions of the cluster

occurs in 5.3, reproduced on 5.4/6.0

current status of DM cluster (execute query-status <task-name> in dmctl)

(paste current status of DM cluster here)

[lance6716]

closed by #5167