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MDEV-26447: mysqldump to use temporary view instead of tables.

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This is particularly important for Azure where there is no
MyISAM support in their MariaDB cloud product.

Like mysqldumper does, a view can satisfy the requirement
like a table, without constraints. The views in frm files are
text form and don't have column limits.

Thanks Thomas Casteleyn for the suggestion.
This commit is contained in:
Daniel Black
2022-07-30 13:29:17 +10:00
parent 53c4e4d054
commit 92b0a367aa
5 changed files with 103 additions and 172 deletions
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51
client/mysqldump.c
View File

@ -3072,9 +3072,8 @@ static uint get_table_structure(const char *table, const char *db, char *table_t
if (strcmp(field->name, "View") == 0)
{
char *scv_buff= NULL;
my_ulonglong n_cols;
verbose_msg("-- It's a view, create dummy table for view\n");
verbose_msg("-- It's a view, create dummy view for view\n");
/* save "show create" statement for later */
if ((row= mysql_fetch_row(result)) && (scv_buff=row[1]))
@ -3083,9 +3082,9 @@ static uint get_table_structure(const char *table, const char *db, char *table_t
mysql_free_result(result);
/*
Create a table with the same name as the view and with columns of
Create a view with the same name as the view and with columns of
the same name in order to satisfy views that depend on this view.
The table will be removed when the actual view is created.
The view will be removed when the actual view is created.
The properties of each column, are not preserved in this temporary
table, because they are not necessary.
@ -3117,23 +3116,9 @@ static uint get_table_structure(const char *table, const char *db, char *table_t
else
my_free(scv_buff);
n_cols= mysql_num_rows(result);
if (0 != n_cols)
if (mysql_num_rows(result) != 0)
{
/*
The actual formula is based on the column names and how the .FRM
files are stored and is too volatile to be repeated here.
Thus we simply warn the user if the columns exceed a limit we
know works most of the time.
*/
if (n_cols >= 1000)
fprintf(stderr,
"-- Warning: Creating a stand-in table for view %s may"
" fail when replaying the dump file produced because "
"of the number of columns exceeding 1000. Exercise "
"caution when replaying the produced dump file.\n",
table);
if (opt_drop)
{
/*
@ -3149,7 +3134,7 @@ static uint get_table_structure(const char *table, const char *db, char *table_t
fprintf(sql_file,
"SET @saved_cs_client = @@character_set_client;\n"
"SET character_set_client = utf8;\n"
"/*!50001 CREATE TABLE %s (\n",
"/*!50001 CREATE VIEW %s AS SELECT\n",
result_table);
/*
@ -3161,28 +3146,21 @@ static uint get_table_structure(const char *table, const char *db, char *table_t
row= mysql_fetch_row(result);
/*
The actual column type doesn't matter anyway, since the table will
The actual column value doesn't matter anyway, since the view will
be dropped at run time.
We do tinyint to avoid hitting the row size limit.
*/
fprintf(sql_file, " %s tinyint NOT NULL",
fprintf(sql_file, " 1 AS %s",
quote_name(row[0], name_buff, 0));
while((row= mysql_fetch_row(result)))
{
/* col name, col type */
fprintf(sql_file, ",\n %s tinyint NOT NULL",
fprintf(sql_file, ",\n 1 AS %s",
quote_name(row[0], name_buff, 0));
}
/*
Stand-in tables are always MyISAM tables as the default
engine might have a column-limit that's lower than the
number of columns in the view, and MyISAM support is
guaranteed to be in the server anyway.
*/
fprintf(sql_file,
"\n) ENGINE=MyISAM */;\n"
" */;\n"
"SET character_set_client = @saved_cs_client;\n");
check_io(sql_file);
@ -6642,15 +6620,8 @@ static my_bool get_view_structure(char *table, char* db)
"\n--\n-- Final view structure for view %s\n--\n\n",
fix_for_comment(result_table));
/* Table might not exist if this view was dumped with --tab. */
fprintf(sql_file, "/*!50001 DROP TABLE IF EXISTS %s*/;\n", opt_quoted_table);
if (opt_drop)
{
fprintf(sql_file, "/*!50001 DROP VIEW IF EXISTS %s*/;\n",
opt_quoted_table);
check_io(sql_file);
}
/* View might not exist if this view was dumped with --tab. */
fprintf(sql_file, "/*!50001 DROP VIEW IF EXISTS %s*/;\n", opt_quoted_table);
my_snprintf(query, sizeof(query),
"SELECT CHECK_OPTION, DEFINER, SECURITY_TYPE, "