Lock wait timeout on DELETE from table using lookup index

[aquarapid]

Scenario:

• Up-to-date master vitess branch (ed51f56)
• examples/local setup done via:

$ cd examples/local/
$ for i in `ls -1 [1-3]*.sh` ; do echo $i ; ./$i ; sleep 5 ; done
.
.

• Apply schema and vschema as indicated to the sharded (customer) keyspace:

$ cat schema.sql 
CREATE TABLE t1 (
    c1 BIGINT NOT NULL,
    c2 INT NOT NULL,
    PRIMARY KEY (c1),
    CONSTRAINT UNIQUE (c2)
);


CREATE TABLE `lookup_t1` (
    c2 INT NOT NULL,
    keyspace_id BINARY(8),
    PRIMARY KEY (c2)
);

$ cat vschema.json 
{
  "sharded": true,
  "vindexes": {
    "hash": { "type": "hash" },
    "xxhash": { "type": "xxhash" },
    "lookup_t1_c2": {
      "type": "consistent_lookup_unique",
      "params": {
        "table": "lookup_t1",
        "from": "c2",
        "to": "keyspace_id",
        "ignore_nulls": "true"
      },
      "owner": "t1"
    }
  },
  "tables": {
    "t1": {
      "columnVindexes": [
        {
          "column": "c1",
          "name": "hash"
        },
        {
          "column": "c2",
          "name": "lookup_t1_c2"
        }
      ],
      "columns": [
        {
          "name": "c1",
          "type": "INT64"
        },
        {
          "name": "c2",
          "type": "INT32"
        }
      ],
      "columnListAuthoritative": true
    },
    "lookup_t1": {
      "columnVindexes": [
        {
          "column": "c2",
          "name": "hash"
        }
      ]
    }
  }
}

$ vtctlclient -server localhost:15999  ApplyVSchema -vschema="$(cat ./vschema.json)" customer
New VSchema object:
.
.
.
$ vtctlclient -server localhost:15999 ApplySchema -sql "$(cat schema.sql)" customer

• Connect to vtgate, verify environment, insert a row and DELETE the row, observing the issue:

$ mysql -u root -P 15306 -h 127.0.0.1 -u root customer -A
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.9-Vitess MySQL Community Server - GPL

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show tables;
+-----------------------+
| Tables_in_vt_customer |
+-----------------------+
| corder                |
| customer              |
| lookup_t1             |
| t1                    |
+-----------------------+
4 rows in set (0.01 sec)

mysql> insert into t1 values (1, 2);
Query OK, 1 row affected (0.01 sec)

mysql> select * from t1;
+----+----+
| c1 | c2 |
+----+----+
|  1 |  2 |
+----+----+
1 row in set (0.01 sec)

mysql> select * from lookup_t1;
+----+--------------------------+
| c2 | keyspace_id              |
+----+--------------------------+
|  2 | 0x166B40B44ABA4BD6       |
+----+--------------------------+
1 row in set (0.00 sec)

mysql> DELETE FROM t1 WHERE c2=2;
<hang for 30 secs>
ERROR 1205 (HY000): vtgate: http://localhost:15001/: execDeleteEqual: lookup.Delete: Code: DEADLINE_EXCEEDED
vttablet: Lock wait timeout exceeded; try restarting transaction (errno 1205) (sqlstate HY000) (CallerID: userData1): Sql: "delete from lookup_t1 where c2 = :c2 and keyspace_id = :keyspace_id", BindVars: {#maxLimit: "type:INT64 value:\"10001\" "c2: "type:INT32 value:\"2\" "keyspace_id: "type:VARBINARY value:\"\\026k@\\264J\\272K\\326\" "}

target: customer.-80.master, used tablet: zone1-300 (localhost)