MDEV-19867: fix mysqldump to by default not copy S3 tables

There are two options when coping S3 tables with mysqldump
(there is startup option --copy_s3_tables, boolean, default no)
1) Ignore all tables with engine S3, as the data is already safe in S3 and any
computer where you restore the backup will automatically discover the S3 table.
2) Copy the table as a normal table with the following 2 changes:
- Change ENGINE=S3 to ENGINE=ARIA;
- After copy add to log 'ALTER TABLE table_name ENGINE=S3'

1 files changed, 55 insertions, 3 deletions

diff --git a/client/mysqldump.c b/client/mysqldump.c
index 38db869c7ac..c64df9e78a9 100644
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -83,6 +83,7 @@
 #define IGNORE_NONE 0x00 /* no ignore */
 #define IGNORE_DATA 0x01 /* don't dump data for this table */
 #define IGNORE_INSERT_DELAYED 0x02 /* table doesn't support INSERT DELAYED */
+#define IGNORE_S3_TABLE 0x04
 
 /* Chars needed to store LONGLONG, excluding trailing '\0'. */
 #define LONGLONG_LEN 20
@@ -100,6 +101,7 @@ static my_bool  verbose= 0, opt_no_create_info= 0, opt_no_data= 0, opt_no_data_m
                 quick= 1, extended_insert= 1,
                 lock_tables=1,ignore_errors=0,flush_logs=0,flush_privileges=0,
                 opt_drop=1,opt_keywords=0,opt_lock=1,opt_compress=0,
+                opt_copy_s3_tables=0,
                 opt_delayed=0,create_options=1,opt_quoted=0,opt_databases=0,
                 opt_alldbs=0,opt_create_db=0,opt_lock_all_tables=0,
                 opt_set_charset=0, opt_dump_date=1,
@@ -273,6 +275,11 @@ static struct my_option my_long_options[] =
   {"compress", 'C', "Use compression in server/client protocol.",
    &opt_compress, &opt_compress, 0, GET_BOOL, NO_ARG, 0, 0, 0,
    0, 0, 0},
+  {"copy_s3_tables", OPT_COPY_S3_TABLES,
+   "If 'no' S3 tables will be ignored, otherwise S3 tables will be copied as "
+   " Aria tables and then altered to S3",
+   &opt_copy_s3_tables, &opt_copy_s3_tables, 0, GET_BOOL, NO_ARG, 0, 0, 0,
+   0, 0, 0},
   {"create-options", 'a',
    "Include all MariaDB specific create options.",
    &create_options, &create_options, 0, GET_BOOL, NO_ARG, 1,
@@ -2143,7 +2150,12 @@ static void print_xml_row(FILE *xml_file, const char *row_name,
         fputc(' ', xml_file);
         print_quoted_xml(xml_file, field->name, field->name_length, 1);
         fputs("=\"", xml_file);
-        print_quoted_xml(xml_file, (*row)[i], lengths[i], 0);
+        if (opt_copy_s3_tables &&
+            !strcmp(field->name, "Engine") &&
+            !strcmp((*row)[i], "S3"))
+          print_quoted_xml(xml_file, "Aria", sizeof("Aria") - 1, 0);
+        else
+          print_quoted_xml(xml_file, (*row)[i], lengths[i], 0);
         fputc('"', xml_file);
         check_io(xml_file);
       }
@@ -2737,11 +2749,18 @@ static uint get_table_structure(char *table, char *db, char *table_type,
   my_bool    is_log_table;
   MYSQL_RES  *result;
   MYSQL_ROW  row;
+  const char *s3_engine_ptr;
+  DYNAMIC_STRING create_table_str;
+  static const char s3_engine_token[]= " ENGINE=S3 ";
+  static const char aria_engine_token[]= " ENGINE=Aria ";
   DBUG_ENTER("get_table_structure");
   DBUG_PRINT("enter", ("db: %s  table: %s", db, table));
 
   *ignore_flag= check_if_ignore_table(table, table_type);
 
+  if (!opt_copy_s3_tables && *ignore_flag == IGNORE_S3_TABLE)
+    DBUG_RETURN(0);
+
   delayed= opt_delayed;
   if (delayed && (*ignore_flag & IGNORE_INSERT_DELAYED))
   {
@@ -2975,11 +2994,22 @@ static uint get_table_structure(char *table, char *db, char *table_type,
       is_log_table= general_log_or_slow_log_tables(db, table);
       if (is_log_table)
         row[1]+= 13; /* strlen("CREATE TABLE ")= 13 */
+      create_table_str.str= row[1];
+      if (opt_copy_s3_tables && (*ignore_flag & IGNORE_S3_TABLE) &&
+          (s3_engine_ptr= strstr(row[1], s3_engine_token)))
+      {
+        init_dynamic_string_checked(&create_table_str, "", 1024, 1024);
+        dynstr_append_mem_checked(&create_table_str, row[1],
+          (uint)(s3_engine_ptr - row[1]));
+        dynstr_append_checked(&create_table_str, aria_engine_token);
+        dynstr_append_checked(&create_table_str,
+          s3_engine_ptr + sizeof(s3_engine_token) - 1);
+      }
       if (opt_compatible_mode & 3)
       {
         fprintf(sql_file,
                 is_log_table ? "CREATE TABLE IF NOT EXISTS %s;\n" : "%s;\n",
-                row[1]);
+                create_table_str.str);
       }
       else
       {
@@ -2989,10 +3019,12 @@ static uint get_table_structure(char *table, char *db, char *table_type,
                 "%s%s;\n"
                 "/*!40101 SET character_set_client = @saved_cs_client */;\n",
                 is_log_table ? "CREATE TABLE IF NOT EXISTS " : "",
-                row[1]);
+                create_table_str.str);
       }
 
       check_io(sql_file);
+      if (create_table_str.str != row[1])
+        dynstr_free(&create_table_str);
       mysql_free_result(result);
     }
     my_snprintf(query_buff, sizeof(query_buff), "show fields from %s",
@@ -3691,6 +3723,14 @@ static void dump_table(char *table, char *db)
   if (strcmp(table_type, "VIEW") == 0)
     DBUG_VOID_RETURN;
 
+  if (!opt_copy_s3_tables && (ignore_flag & IGNORE_S3_TABLE))
+  {
+    verbose_msg("-- Skipping dump data for table '%s', "
+                " this is S3 table and --copy-s3-tables=0\n",
+                table);
+    DBUG_VOID_RETURN;
+  }
+
   /* Check --no-data flag */
   if (opt_no_data)
   {
@@ -4118,6 +4158,15 @@ static void dump_table(char *table, char *db)
         fputs("\t</table_data>\n", md_result_file);
     else if (extended_insert && row_break)
       fputs(";\n", md_result_file);             /* If not empty table */
+    if (!opt_xml && opt_copy_s3_tables && (ignore_flag & IGNORE_S3_TABLE))
+    {
+      DYNAMIC_STRING alter_string;
+      init_dynamic_string_checked(&alter_string, "ATER TABLE ", 1024, 1024);
+      dynstr_append_checked(&alter_string, opt_quoted_table);
+      dynstr_append_checked(&alter_string, " ENGINE=S3;\n");
+      fputs(alter_string.str, md_result_file);
+      dynstr_free(&alter_string);
+    }
     fflush(md_result_file);
     check_io(md_result_file);
     if (mysql_errno(mysql))
@@ -5684,6 +5733,9 @@ char check_if_ignore_table(const char *table_name, char *table_type)
         result= IGNORE_INSERT_DELAYED;
     }
 
+    if (!strcmp(table_type, "S3"))
+       result|= IGNORE_S3_TABLE;
+
     /*
       If these two types, we do want to skip dumping the table
     */