MDEV-19597 Refactor TABLE::vers_update_fields() via stored virtual columns

[midenok]

Instead of vers_update_fields() use vcol expression to update system field values on DML.

Outdated

Instead of vers_update_fields() use Item_default_value and update system values in update_default_fields() (see both fill_record()).

Check all_fields_have_values and set_explicit_default().

[midenok]

Related to MDEV-16937 Strict SQL with system versioned tables causes issues.

Related to #591

[midenok]

Info

create or replace table d1 (x int default (1));
insert into d values (default);

1. TABLE::default_field set

#0  open_table_from_share (thd=0x7fff78000d50, share=0x7fff7801bcf8, alias=0x7fffe4ed1020, db_stat=33, prgflag=8, ha_open_flags=16, outparam=0x7fff7801e030, is_create_table=false, partitions_to_open=0x0) at /home/midenok/src/mariadb/trunk/src/sql/table.cc:3260
#1  0x0000000000705b9f in open_table (thd=0x7fff78000d50, table_list=0x7fffe4ed0fd8, ot_ctx=0x7fffe4ed06f8) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:1937
#2  0x0000000000709f18 in open_and_process_table (thd=0x7fff78000d50, lex=0x7fff78004af0, tables=0x7fffe4ed0fd8, counter=0x7fffe4ed0844, flags=1024, prelocking_strategy=0x7fffe4ed0848, has_prelocking_list=false, ot_ctx=0x7fffe4ed06f8) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:3545
#3  0x0000000000708c6d in open_tables (thd=0x7fff78000d50, options=..., start=0x7fffe4ed0858, counter=0x7fffe4ed0844, flags=1024, prelocking_strategy=0x7fffe4ed0848) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:4063
#4  0x000000000070d835 in open_tables (thd=0x7fff78000d50, tables=0x7fffe4ed0858, counter=0x7fffe4ed0844, flags=1024, prelocking_strategy=0x7fffe4ed0848) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.h:245
#5  0x000000000070d5e8 in open_normal_and_derived_tables (thd=0x7fff78000d50, tables=0x7fffe4ed0fd8, flags=1024, dt_phases=35) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:5003
#6  0x000000000086bd37 in mysqld_list_fields (thd=0x7fff78000d50, table_list=0x7fffe4ed0fd8, wild=0x7fff78013ad8 "") at /home/midenok/src/mariadb/trunk/src/sql/sql_show.cc:1527
#7  0x00000000007ae8bb in dispatch_command (command=COM_FIELD_LIST, thd=0x7fff78000d50, packet=0x7fff7800b2d3 "", packet_length=2, is_com_multi=false, is_next_command=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:2040

2. Item_default_value constructed

#0  Item_default_value::Item_default_value (this=0x7fff78014208, thd=0x7fff78000d50, context_arg=0x7fff78005370) at /home/midenok/src/mariadb/trunk/src/sql/item.h:5792
#1  0x0000000000a52900 in MYSQLparse (thd=0x7fff78000d50) at /home/midenok/src/mariadb/trunk/src/sql/sql_yacc.yy:13329
#2  0x00000000007c717a in parse_sql (thd=0x7fff78000d50, parser_state=0x7fffe4ed1650, creation_ctx=0x0, do_pfs_digest=true) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:10088
#3  0x00000000007b21f0 in mysql_parse (thd=0x7fff78000d50, rawbuf=0x7fff78013ab8 "insert into d values (default)", length=30, parser_state=0x7fffe4ed1650, is_com_multi=false, is_next_command=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:8030

3. set_explicit_default() called

#0  Field::set_explicit_default (this=0x7fff7801f498, value=0x7fff78014208) at /home/midenok/src/mariadb/trunk/src/sql/field.cc:11260
#1  0x0000000000715df7 in fill_record (thd=0x7fff78000d50, table=0x7fff7801e030, ptr=0x7fff7801f490, values=..., ignore_errors=false, use_value=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:8501
#2  0x000000000071605f in fill_record_n_invoke_before_triggers (thd=0x7fff78000d50, table=0x7fff7801e030, ptr=0x7fff7801f488, values=..., ignore_errors=false, event=TRG_EVENT_INSERT) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:8552
#3  0x000000000076aa70 in mysql_insert (thd=0x7fff78000d50, table_list=0x7fff78013ba0, fields=..., values_list=..., update_fields=..., update_values=..., duplic=DUP_ERROR, ignore=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_insert.cc:1006
#4  0x00000000007baab3 in mysql_execute_command (thd=0x7fff78000d50) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:4720
#5  0x00000000007b241f in mysql_parse (thd=0x7fff78000d50, rawbuf=0x7fff78013ab8 "insert into d values (default)", length=30, parser_state=0x7fffe4ed1650, is_com_multi=false, is_next_command=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:8077

4. update_default_fields() called

#0  TABLE::update_default_fields (this=0x7fff7801e030, update_command=false, ignore_errors=false) at /home/midenok/src/mariadb/trunk/src/sql/table.cc:7669
#1  0x0000000000715e57 in fill_record (thd=0x7fff78000d50, table=0x7fff7801e030, ptr=0x7fff7801f498, values=..., ignore_errors=false, use_value=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:8504
#2  0x000000000071605f in fill_record_n_invoke_before_triggers (thd=0x7fff78000d50, table=0x7fff7801e030, ptr=0x7fff7801f488, values=..., ignore_errors=false, event=TRG_EVENT_INSERT) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:8552
#3  0x000000000076aa70 in mysql_insert (thd=0x7fff78000d50, table_list=0x7fff78013ba0, fields=..., values_list=..., update_fields=..., update_values=..., duplic=DUP_ERROR, ignore=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_insert.cc:1006
#4  0x00000000007baab3 in mysql_execute_command (thd=0x7fff78000d50) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:4720
#5  0x00000000007b241f in mysql_parse (thd=0x7fff78000d50, rawbuf=0x7fff78013ab8 "insert into d values (default)", length=30, parser_state=0x7fffe4ed1650, is_com_multi=false, is_next_command=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:8077

[midenok]

Virtual_column_info constructed

1. in TABLE_SHARE

#0  Virtual_column_info::Virtual_column_info (this=0x7fff780bee80) at /home/midenok/src/mariadb/trunk/src/sql/field.h:573
#1  0x00000000008f6bf6 in TABLE_SHARE::init_from_binary_frm_image (this=0x7fffe4ecac70, thd=0x7fff78000d50, write=true, frm_image=0x7fff78022a30 "\376\001\n\f\022", frm_length=432) at /home/midenok/src/mariadb/trunk/src/sql/table.cc:1998

1995        if (unireg_check == Field::TIMESTAMP_DNUN_FIELD ||
1996            unireg_check == Field::TIMESTAMP_DN_FIELD)
1997        {
1998          reg_field->default_value= new (&share->mem_root) Virtual_column_info();
1999          reg_field->default_value->set_vcol_type(VCOL_DEFAULT);
2000          reg_field->default_value->stored_in_db= 1;
2001          share->default_expressions++;
2002        }

2. in TABLE

#0  Virtual_column_info::Virtual_column_info (this=0x7fff780b9f08) at /home/midenok/src/mariadb/trunk/src/sql/field.h:573
#1  0x0000000000a2508a in add_virtual_expression (thd=0x7fff78000d50, expr=0x7fff780b9e18) at /home/midenok/src/mariadb/trunk/src/sql/sql_yacc.yy:762
#2  0x0000000000a32b2d in MYSQLparse (thd=0x7fff78000d50) at /home/midenok/src/mariadb/trunk/src/sql/sql_yacc.yy:6736
#3  0x00000000007c717a in parse_sql (thd=0x7fff78000d50, parser_state=0x7fffe4eca180, creation_ctx=0x0, do_pfs_digest=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:10088
#4  0x00000000008fabd0 in unpack_vcol_info_from_frm (thd=0x7fff78000d50, mem_root=0x7fffe4ecbe78, table=0x7fffe4ecb3b0, expr_str=0x7fffe4eca4f8, vcol_ptr=0x7fff780b9d50, error_reported=0x7fffe4ecab53) at /home/midenok/src/mariadb/trunk/src/sql/table.cc:2994
#5  0x00000000008fa5e5 in parse_vcol_defs (thd=0x7fff78000d50, mem_root=0x7fffe4ecbe78, table=0x7fffe4ecb3b0, error_reported=0x7fffe4ecab53) at /home/midenok/src/mariadb/trunk/src/sql/table.cc:1108
#6  0x00000000008fdb68 in open_table_from_share (thd=0x7fff78000d50, share=0x7fffe4ecac70, alias=0x1cf5278 <empty_clex_str>, db_stat=0, prgflag=1, ha_open_flags=0, outparam=0x7fffe4ecb3b0, is_create_table=true, partitions_to_open=0x0) at /home/midenok/src/mariadb/trunk/src/sql/table.cc:3264

760     Virtual_column_info *add_virtual_expression(THD *thd, Item *expr)
761     {
762       Virtual_column_info *v= new (thd->mem_root) Virtual_column_info();
763       if (unlikely(!v))
764          return 0;
765        v->expr= expr;
766        v->utf8= 0;  /* connection charset */
767        return v;
768     }

6724    parse_vcol_expr:
6725              PARSE_VCOL_EXPR_SYM
6726              {
6727                /*
6728                  "PARSE_VCOL_EXPR" can only be used by the SQL server
6729                  when reading a '*.frm' file.
6730                  Prevent the end user from invoking this command.
6731                */
6732                MYSQL_YYABORT_UNLESS(Lex->parse_vcol_expr);
6733              }
6734              expr
6735              {
6736                Virtual_column_info *v= add_virtual_expression(thd, $3);
6737                if (unlikely(!v))
6738                  MYSQL_YYABORT;
6739                Lex->last_field->vcol_info= v;
6740              }
6741            ;

0. in parser

field_def:
          opt_attribute
        | opt_generated_always AS virtual_column_func
         {
           Lex->last_field->vcol_info= $3;
           Lex->last_field->flags&= ~NOT_NULL_FLAG; // undo automatic NOT NULL for timestamps
         }
...
virtual_column_func:
          '(' parenthesized_expr ')'
          {
            Virtual_column_info *v=
              add_virtual_expression(thd, $2);
            if (unlikely(!v))
              MYSQL_YYABORT;
            $$= v;
          }
        ;

[midenok]

DEFAULT value assigned to field

#0  Field::set_default (this=0x7fff78055690) at /home/midenok/src/mariadb/trunk/src/sql/field.cc:2385
#1  0x0000000000af21d8 in Field::save_in_field_default_value (this=0x7fff78055690, view_error_processing=false) at /home/midenok/src/mariadb/trunk/src/sql/field.cc:11319
#2  0x0000000000b46f01 in Item_default_value::save_in_field (this=0x7fff78014530, field_arg=0x7fff78055690, no_conversions=false) at /home/midenok/src/mariadb/trunk/src/sql/item.cc:9414
#3  0x0000000000714ff6 in fill_record (thd=0x7fff78000d50, table_arg=0x7fff78054100, fields=..., values=..., ignore_errors=false, update=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:8209
#4  0x00000000007156c8 in fill_record_n_invoke_before_triggers (thd=0x7fff78000d50, table=0x7fff78054100, fields=..., values=..., ignore_errors=false, event=TRG_EVENT_INSERT) at /home/midenok/src/mariadb/trunk/src/sql/sql_base.cc:8382
#5  0x000000000076a876 in mysql_insert (thd=0x7fff78000d50, table_list=0x7fff78013bc8, fields=..., values_list=..., update_fields=..., update_values=..., duplic=DUP_ERROR, ignore=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_insert.cc:960
#6  0x00000000007baab3 in mysql_execute_command (thd=0x7fff78000d50) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:4720
#7  0x00000000007b241f in mysql_parse (thd=0x7fff78000d50, rawbuf=0x7fff78013ab8 "insert into t1 (x, row_start) values (1, DEFAULT)", length=49, parser_state=0x7fffe4ed1650, is_com_multi=false, is_next_command=false) at /home/midenok/src/mariadb/trunk/src/sql/sql_parse.cc:8077

2374    int Field::set_default()
2375    {
2376      if (default_value)
2377      {
2378        Query_arena backup_arena;
2379        table->in_use->set_n_backup_active_arena(table->expr_arena, &backup_arena);
2380        int rc= default_value->expr->save_in_field(this, 0);
2381        table->in_use->restore_active_arena(table->expr_arena, &backup_arena);
2382        return rc;
2383      }
2384      /* Copy constant value stored in s->default_values */
2385      my_ptrdiff_t l_offset= (my_ptrdiff_t) (table->s->default_values -
2386                                            table->record[0]);
2387      memcpy(ptr, ptr + l_offset, pack_length());
2388      if (maybe_null_in_table())
2389        *null_ptr= ((*null_ptr & (uchar) ~null_bit) |
2390                    (null_ptr[l_offset] & null_bit));
2391      return 0;
2392    }