maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Anel!

On Nov 01, Anel Husakovic wrote:
> revision-id: bb1737b0482 (mariadb-10.6.1-73-gbb1737b0482)
> parent(s): 1bc82aaf0a7
> author: Anel Husakovic
> committer: Anel Husakovic
> timestamp: 2021-09-06 08:58:46 +0200
> message:
> 
> MDEV-12459: The information_schema tables for getting temporary tables info is missing, at least for innodb there is no INNODB_TEMP_TABLE_INFO
> 
> diff --git a/sql/sql_show.cc b/sql/sql_show.cc
> index 6b351726320..5444de8c1ca 100644
> --- a/sql/sql_show.cc
> +++ b/sql/sql_show.cc
> @@ -69,6 +69,8 @@
>  
>  #include "lex_symbol.h"
>  #define KEYWORD_SIZE 64
> +#define IS_USER_TEMP_TABLE(A) ((A->tmp_table == TRANSACTIONAL_TMP_TABLE) || \
> +                          (A->tmp_table == NON_TRANSACTIONAL_TMP_TABLE))
>  
>  extern SYMBOL symbols[];
>  extern size_t symbols_length;
> @@ -151,6 +153,8 @@ static int show_create_sequence(THD *thd, TABLE_LIST *table_list,
>  static const LEX_CSTRING *view_algorithm(TABLE_LIST *table);
>  
>  bool get_lookup_field_values(THD *, COND *, TABLE_LIST *, LOOKUP_FIELD_VALUES *);
> +void process_i_s_table_temporary_tables(THD *thd, TABLE * table, LEX_CSTRING *db_name,
> +                                        LEX_CSTRING *table_name, TABLE *tmp_tbl);
>  
>  /**
>    Try to lock a mutex, but give up after a short while to not cause deadlocks
> @@ -5161,6 +5166,10 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
>    uint table_open_method= tables->table_open_method;
>    bool can_deadlock;
>    MEM_ROOT tmp_mem_root;
> +  Dynamic_array<LEX_CSTRING> system_tables(PSI_INSTRUMENT_MEM);
> +  All_tmp_tables_list *temp_tables= NULL;
> +  // Scan for temporary tables
> +  TMP_TABLE_SHARE *share_temp;
>    DBUG_ENTER("get_all_tables");
>  
>    bzero(&tmp_mem_root, sizeof(tmp_mem_root));
> @@ -5223,6 +5232,12 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
>    init_alloc_root(PSI_INSTRUMENT_ME, &tmp_mem_root, SHOW_ALLOC_BLOCK_SIZE,
>                    SHOW_ALLOC_BLOCK_SIZE, MY_THREAD_SPECIFIC);
>  
> +  system_tables.push(INFORMATION_SCHEMA_NAME);
> +  system_tables.push(PERFORMANCE_SCHEMA_DB_NAME);
> +  system_tables.push(MYSQL_SCHEMA_NAME);
> +  system_tables.push(SYS_SCHEMA_NAME);
> +  system_tables.push(MTR_SCHEMA_NAME);
> +
>    for (size_t i=0; i < db_names.elements(); i++)
>    {
>      LEX_CSTRING *db_name= db_names.at(i);
> @@ -5234,6 +5249,36 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
>          sctx->master_access & (DB_ACLS | SHOW_DB_ACL) ||
>          acl_get(sctx->host, sctx->ip, sctx->priv_user, db_name->str, 0))
>  #endif
> +
> +    // Only if there is IS.tables allow temporary tables to be shown
> +    if (schema_table_idx == SCH_TABLES && !temp_tables)
> +    {
> +      for (size_t k=0; k < system_tables.elements(); k++)
> +      {
> +        if (db_name != &system_tables.at(k))
> +        {
> +          temp_tables= open_tables_state_backup.temporary_tables;
> +          if (temp_tables)
> +          {
> +            All_tmp_tables_list::Iterator it(*open_tables_state_backup.temporary_tables);
> +            while ((share_temp= it++))
> +            {
> +              All_share_tables_list::Iterator it2(share_temp->all_tmp_tables);
> +              while (TABLE *tbl= it2++)
> +              {
> +                if (IS_USER_TEMP_TABLE(share_temp))
> +                {
> +                  // Now we have the data and we should process_table() manually
> +                  process_i_s_table_temporary_tables(thd, table, db_name,
> +                                                    &share_temp->table_name, tbl);
> +                }
> +              }
> +            }
> +          }
> +          break;
> +        }
> +      }
> +    }

hmmmm. What do you do here? I understand, basically, nothing here.
Could you explain, line by line?

>      {
>        Dynamic_array<LEX_CSTRING*> table_names(PSI_INSTRUMENT_MEM);
>        int res= make_table_name_list(thd, &table_names, lex,
> @@ -5495,6 +5540,8 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
>        table->field[3]->store(STRING_WITH_LEN("SYSTEM VIEW"), cs);
>      else if (share->table_type == TABLE_TYPE_SEQUENCE)
>        table->field[3]->store(STRING_WITH_LEN("SEQUENCE"), cs);
> +    else if (IS_USER_TEMP_TABLE(share))
> +      table->field[3]->store(STRING_WITH_LEN("TEMPORARY"), cs);

what about   INTERNAL_TMP_TABLE and SYSTEM_TMP_TABLE?

>      else
>      {
>        DBUG_ASSERT(share->tmp_table == NO_TMP_TABLE);
> @@ -9032,7 +9096,6 @@ ST_FIELD_INFO tables_fields_info[]=
>                                           NOT_NULL, "Comment",    OPEN_FRM_ONLY),
>    Column("MAX_INDEX_LENGTH",ULonglong(), NULLABLE, "Max_index_length",
>                                                                   OPEN_FULL_TABLE),
> -  Column("TEMPORARY",       Varchar(1),  NULLABLE, "Temporary",  OPEN_FRM_ONLY),
>    CEnd()
>  };

Let's remove it in a separate commit. After you implement "TEMPORARY"
for table type.

Regards,
Sergei
VP of MariaDB Server Engineering
and security@xxxxxxxxxxx