bug: truncate table failed

[hustjieke]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Please confirm if bug report does NOT exists already ?

• I confirm there is no existing issue for this

Describe the problem

Execute truncate table t with no effect, the data didn't be truncated.

Expected behavior

No response

How To Reproduce

talbe schema :
create table t2(a int key, b int) engine = tianmu;
insert into t2 values ....

mysql> truncate table t2;
Query OK, 0 rows affected (39.39 sec)

mysql> select * from t2;
+---+------+
| a | b    |
+---+------+
| 1 |    1 |
| 2 |    3 |
| 3 |    4 |
| 5 |    5 |
| 6 |    6 |
| 8 |    8 |
| 7 |    7 |
| 9 |    9 |
+---+------+
8 rows in set (0.72 sec)

Environment

1. ubuntu
2. stonedb-8.0-dev

Are you interested in submitting a PR to solve the problem?

• Yes, I will!

[hustjieke]

When mysql has done locked table in function external_lock(), it continuely doing unlock_external(), this make m_modified_tables been clear in advance on tianmu transaction.

1. doing external_lock in handler_truncate_base in line 569:
2. then do unlock_external in line 592

   563           /*                                                                                                                                                                               │
│   564             The engine does not support truncate-by-recreate.                                                                                                                              │
│   565             Attempt to use the handler truncate method.                                                                                                                                    │
│   566             MYSQL_AUDIT_TABLE_ACCESS_READ audit event is generated when opening                                                                                                            │
│   567             tables using open_tables function.                                                                                                                                             │
│   568           */                                                                                                                                                                               │
│b+ 569           const Truncate_result tr = handler_truncate_base(thd, table_ref, table_def);                                                                                                     │
│   570           switch (tr) {                                                                                                                                                                    │
│   571               /*                                                                                                                                                                           │
│   572                 All effects of a TRUNCATE TABLE operation are committed even if                                                                                                            │
│   573                 truncation fails in the case of non transactional tables. Thus, the                                                                                                        │
│   574                 query must be written to the binary log for such tables.                                                                                                                   │
│   575                 The exceptions are failure to open table or unimplemented truncate                                                                                                         │
│   576                 method.                                                                                                                                                                    │
│   577               */                                                                                                                                                                           │
│   578             case Truncate_result::OK:                                                                                                                                                      │
│   579               m_error = false;                                                                                                                                                             │
│   580               [[fallthrough]];                                                                                                                                                             │
│   581             case Truncate_result::FAILED_BUT_BINLOG:                                                                                                                                       │
│   582               binlog_stmt = true;                                                                                                                                                          │
│   583               binlog_is_trans = table_ref->table->file->has_transactions();                                                                                                                │
│   584               [[fallthrough]];                                                                                                                                                             │
│   585             case Truncate_result::FAILED_SKIP_BINLOG:                                                                                                                                      │
│   586               /*                                                                                                                                                                           │
│   587                 Call to handler_truncate() might have updated table definition                                                                                                             │
│   588                 in the data-dictionary, let us remove TABLE_SHARE from the TDC.                                                                                                            │
│   589                 This needs to be done even in case of failure so InnoDB SE                                                                                                                 │
│   590                 properly invalidates its internal cache.                                                                                                                                   │
│   591               */                                                                                                                                                                           │
│   592               close_all_tables_for_name(thd, table_ref->table->s, false, nullptr);                                                                                                         │
│  >593               break;  

btrace in gdb when doingunlock_external :

#0  Tianmu::core::Transaction::RemoveTable (this=0x7efd300b22a0, share=std::shared_ptr<Tianmu::core::TableShare> (use count 2, weak count 0) = {...})
    at /github/stonedb/storage/tianmu/core/transaction.cpp:56
#1  0x0000557458f00501 in Tianmu::handler::ha_tianmu::external_lock (this=0x7efd3000c770, thd=0x7efd30001060, lock_type=2) at /github/stonedb/storage/tianmu/handler/ha_tianmu.cpp:274
#2  0x00005574570c3bc7 in handler::ha_external_lock (this=0x7efd3000c770, thd=0x7efd30001060, lock_type=2) at /github/stonedb/sql/handler.cc:7793
#3  0x000055745731281e in unlock_external (thd=0x7efd30001060, table=0x7efd3009f3d8, count=1) at /github/stonedb/sql/lock.cc:618
#4  0x0000557457311e5c in mysql_unlock_tables (thd=0x7efd30001060, sql_lock=0x7efd3009f3b0) at /github/stonedb/sql/lock.cc:414
#5  0x0000557457311f02 in mysql_unlock_some_tables (thd=0x7efd30001060, table=0x7f026c21df08, count=1) at /github/stonedb/sql/lock.cc:427
#6  0x0000557457312225 in mysql_lock_remove (thd=0x7efd30001060, locked=0x7efd300a07f0, table=0x7efd309911a0) at /github/stonedb/sql/lock.cc:503
#7  0x0000557456b9841e in close_all_tables_for_name (thd=0x7efd30001060, key=0x7f026c21dfe0 "test", key_length=8, db=0x7f026c21dfe0 "test", table_name=0x7f026c21dfe5 "t2",
    remove_from_locked_tables=false, skip_table=0x0) at /github/stonedb/sql/sql_base.cc:1463
#8  0x0000557456b98563 in close_all_tables_for_name (thd=0x7efd30001060, share=0x7efd300b4350, remove_from_locked_tables=false, skip_table=0x0) at /github/stonedb/sql/sql_base.cc:1489
#9  0x000055745744c571 in Sql_cmd_truncate_table::truncate_base (this=0x7efd300a6530, thd=0x7efd30001060, table_ref=0x7efd300a6568) at /github/stonedb/sql/sql_truncate.cc:592
#10 0x000055745744cf8f in Sql_cmd_truncate_table::execute (this=0x7efd300a6530, thd=0x7efd30001060) at /github/stonedb/sql/sql_truncate.cc:740
#11 0x0000557456cb4185 in mysql_execute_command (thd=0x7efd30001060, first_level=true) at /github/stonedb/sql/sql_parse.cc:4604
#12 0x0000557456cb6470 in dispatch_sql_command (thd=0x7efd30001060, parser_state=0x7f026c21fb90) at /github/stonedb/sql/sql_parse.cc:5239
#13 0x0000557456cabeef in dispatch_command (thd=0x7efd30001060, com_data=0x7f026c2204e0, command=COM_QUERY) at /github/stonedb/sql/sql_parse.cc:1959
#14 0x0000557456ca9f66 in do_command (thd=0x7efd30001060) at /github/stonedb/sql/sql_parse.cc:1362

[hustjieke]

This problom only exists in 8.0, 5.7 is ok.