MDEV-34716 spider: some trivial cleanups and documentation

- document tmp_share, which are temporary spider shares with only one
link (no ha)
- simplify spider_get_sys_tables_connect_info() where link_idx is
always 0

storage/spider/spd_copy_tables.cc

@@ -246,6 +246,7 @@ int spider_udf_get_copy_tgt_tables(
   char table_key[MAX_KEY_LENGTH];
   SPIDER_COPY_TABLE_CONN *table_conn = NULL, *src_table_conn_prev = NULL,
     *dst_table_conn_prev = NULL;
+  /* This share has only one link. */
   SPIDER_SHARE *tmp_share;
   char **tmp_connect_info;
   uint *tmp_connect_info_length;

storage/spider/spd_include.h

@@ -1465,6 +1465,7 @@ typedef struct st_spider_mon_table_result
 
 typedef struct st_spider_table_mon
 {
+  /* This share has only one link. */
   SPIDER_SHARE               *share;
   uint32                     server_id;
   st_spider_table_mon_list   *parent;
@@ -1491,6 +1492,7 @@ typedef struct st_spider_table_mon_list
   SPIDER_TABLE_MON           *current;
   volatile int               mon_status;
 
+  /* This share has only one link */
   SPIDER_SHARE               *share;
 
   pthread_mutex_t            caller_mutex;
@@ -1504,6 +1506,7 @@ typedef struct st_spider_table_mon_list
 
 typedef struct st_spider_copy_table_conn
 {
+  /* This share has only one link. */
   SPIDER_SHARE               *share;
   int                        link_idx;
   SPIDER_CONN                *conn;

storage/spider/spd_sys_table.cc

@@ -2161,9 +2161,7 @@ int spider_get_sys_tables_connect_info(
 ) {
   char *ptr;
   int error_num = 0;
-  const int link_idx= 0;
   DBUG_ENTER("spider_get_sys_tables_connect_info");
-  DBUG_PRINT("info",("spider link_idx:%d", link_idx));
   if ((ptr = get_field(mem_root, table->field[SPIDER_TABLES_PRIORITY_POS])))
   {
     share->priority = my_strtoll10(ptr, (char**) NULL, &error_num);
@@ -2174,245 +2172,245 @@ int spider_get_sys_tables_connect_info(
     !table->field[SPIDER_TABLES_SERVER_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SERVER_POS]))
   ) {
-    share->server_names_lengths[link_idx] = strlen(ptr);
-    share->server_names[link_idx] =
-      spider_create_string(ptr, share->server_names_lengths[link_idx]);
+    share->server_names_lengths[0] = strlen(ptr);
+    share->server_names[0] =
+      spider_create_string(ptr, share->server_names_lengths[0]);
     DBUG_PRINT("info",("spider server_name:%s",
-      share->server_names[link_idx]));
+      share->server_names[0]));
   } else {
-    share->server_names_lengths[link_idx] = 0;
-    share->server_names[link_idx] = NULL;
+    share->server_names_lengths[0] = 0;
+    share->server_names[0] = NULL;
     DBUG_PRINT("info",("spider server_name is NULL"));
   }
   if (
     !table->field[SPIDER_TABLES_SCHEME_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SCHEME_POS]))
   ) {
-    share->tgt_wrappers_lengths[link_idx] = strlen(ptr);
-    share->tgt_wrappers[link_idx] =
-      spider_create_string(ptr, share->tgt_wrappers_lengths[link_idx]);
+    share->tgt_wrappers_lengths[0] = strlen(ptr);
+    share->tgt_wrappers[0] =
+      spider_create_string(ptr, share->tgt_wrappers_lengths[0]);
     DBUG_PRINT("info",("spider tgt_wrapper:%s",
-      share->tgt_wrappers[link_idx]));
+      share->tgt_wrappers[0]));
   } else {
-    share->tgt_wrappers_lengths[link_idx] = 0;
-    share->tgt_wrappers[link_idx] = NULL;
+    share->tgt_wrappers_lengths[0] = 0;
+    share->tgt_wrappers[0] = NULL;
     DBUG_PRINT("info",("spider tgt_wrapper is NULL"));
   }
   if (
     !table->field[SPIDER_TABLES_HOST_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_HOST_POS]))
   ) {
-    share->tgt_hosts_lengths[link_idx] = strlen(ptr);
-    share->tgt_hosts[link_idx] =
-      spider_create_string(ptr, share->tgt_hosts_lengths[link_idx]);
+    share->tgt_hosts_lengths[0] = strlen(ptr);
+    share->tgt_hosts[0] =
+      spider_create_string(ptr, share->tgt_hosts_lengths[0]);
     DBUG_PRINT("info",("spider tgt_host:%s",
-      share->tgt_hosts[link_idx]));
+      share->tgt_hosts[0]));
   } else {
-    share->tgt_hosts_lengths[link_idx] = 0;
-    share->tgt_hosts[link_idx] = NULL;
+    share->tgt_hosts_lengths[0] = 0;
+    share->tgt_hosts[0] = NULL;
     DBUG_PRINT("info",("spider tgt_host is NULL"));
   }
   if (
     !table->field[SPIDER_TABLES_PORT_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_PORT_POS]))
   ) {
-    share->tgt_ports[link_idx] = atol(ptr);
+    share->tgt_ports[0] = atol(ptr);
   } else {
-    share->tgt_ports[link_idx] = -1;
+    share->tgt_ports[0] = -1;
   }
-  DBUG_PRINT("info",("spider port:%ld", share->tgt_ports[link_idx]));
+  DBUG_PRINT("info",("spider port:%ld", share->tgt_ports[0]));
   if (
     !table->field[SPIDER_TABLES_SOCKET_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SOCKET_POS]))
   ) {
-    share->tgt_sockets_lengths[link_idx] = strlen(ptr);
-    share->tgt_sockets[link_idx] =
-      spider_create_string(ptr, share->tgt_sockets_lengths[link_idx]);
+    share->tgt_sockets_lengths[0] = strlen(ptr);
+    share->tgt_sockets[0] =
+      spider_create_string(ptr, share->tgt_sockets_lengths[0]);
   } else {
-    share->tgt_sockets_lengths[link_idx] = 0;
-    share->tgt_sockets[link_idx] = NULL;
+    share->tgt_sockets_lengths[0] = 0;
+    share->tgt_sockets[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_USERNAME_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_USERNAME_POS]))
   ) {
-    share->tgt_usernames_lengths[link_idx] = strlen(ptr);
-    share->tgt_usernames[link_idx] =
-      spider_create_string(ptr, share->tgt_usernames_lengths[link_idx]);
+    share->tgt_usernames_lengths[0] = strlen(ptr);
+    share->tgt_usernames[0] =
+      spider_create_string(ptr, share->tgt_usernames_lengths[0]);
   } else {
-    share->tgt_usernames_lengths[link_idx] = 0;
-    share->tgt_usernames[link_idx] = NULL;
+    share->tgt_usernames_lengths[0] = 0;
+    share->tgt_usernames[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_PASSWORD_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_PASSWORD_POS]))
   ) {
-    share->tgt_passwords_lengths[link_idx] = strlen(ptr);
-    share->tgt_passwords[link_idx] =
-      spider_create_string(ptr, share->tgt_passwords_lengths[link_idx]);
+    share->tgt_passwords_lengths[0] = strlen(ptr);
+    share->tgt_passwords[0] =
+      spider_create_string(ptr, share->tgt_passwords_lengths[0]);
   } else {
-    share->tgt_passwords_lengths[link_idx] = 0;
-    share->tgt_passwords[link_idx] = NULL;
+    share->tgt_passwords_lengths[0] = 0;
+    share->tgt_passwords[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_SSL_CA_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SSL_CA_POS]))
   ) {
-    share->tgt_ssl_cas_lengths[link_idx] = strlen(ptr);
-    share->tgt_ssl_cas[link_idx] =
-      spider_create_string(ptr, share->tgt_ssl_cas_lengths[link_idx]);
+    share->tgt_ssl_cas_lengths[0] = strlen(ptr);
+    share->tgt_ssl_cas[0] =
+      spider_create_string(ptr, share->tgt_ssl_cas_lengths[0]);
   } else {
-    share->tgt_ssl_cas_lengths[link_idx] = 0;
-    share->tgt_ssl_cas[link_idx] = NULL;
+    share->tgt_ssl_cas_lengths[0] = 0;
+    share->tgt_ssl_cas[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_SSL_CAPATH_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SSL_CAPATH_POS]))
   ) {
-    share->tgt_ssl_capaths_lengths[link_idx] = strlen(ptr);
-    share->tgt_ssl_capaths[link_idx] =
-      spider_create_string(ptr, share->tgt_ssl_capaths_lengths[link_idx]);
+    share->tgt_ssl_capaths_lengths[0] = strlen(ptr);
+    share->tgt_ssl_capaths[0] =
+      spider_create_string(ptr, share->tgt_ssl_capaths_lengths[0]);
   } else {
-    share->tgt_ssl_capaths_lengths[link_idx] = 0;
-    share->tgt_ssl_capaths[link_idx] = NULL;
+    share->tgt_ssl_capaths_lengths[0] = 0;
+    share->tgt_ssl_capaths[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_SSL_CERT_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SSL_CERT_POS]))
   ) {
-    share->tgt_ssl_certs_lengths[link_idx] = strlen(ptr);
-    share->tgt_ssl_certs[link_idx] =
-      spider_create_string(ptr, share->tgt_ssl_certs_lengths[link_idx]);
+    share->tgt_ssl_certs_lengths[0] = strlen(ptr);
+    share->tgt_ssl_certs[0] =
+      spider_create_string(ptr, share->tgt_ssl_certs_lengths[0]);
   } else {
-    share->tgt_ssl_certs_lengths[link_idx] = 0;
-    share->tgt_ssl_certs[link_idx] = NULL;
+    share->tgt_ssl_certs_lengths[0] = 0;
+    share->tgt_ssl_certs[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_SSL_CIPHER_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SSL_CIPHER_POS]))
   ) {
-    share->tgt_ssl_ciphers_lengths[link_idx] = strlen(ptr);
-    share->tgt_ssl_ciphers[link_idx] =
-      spider_create_string(ptr, share->tgt_ssl_ciphers_lengths[link_idx]);
+    share->tgt_ssl_ciphers_lengths[0] = strlen(ptr);
+    share->tgt_ssl_ciphers[0] =
+      spider_create_string(ptr, share->tgt_ssl_ciphers_lengths[0]);
   } else {
-    share->tgt_ssl_ciphers_lengths[link_idx] = 0;
-    share->tgt_ssl_ciphers[link_idx] = NULL;
+    share->tgt_ssl_ciphers_lengths[0] = 0;
+    share->tgt_ssl_ciphers[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_SSL_KEY_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_SSL_KEY_POS]))
   ) {
-    share->tgt_ssl_keys_lengths[link_idx] = strlen(ptr);
-    share->tgt_ssl_keys[link_idx] =
-      spider_create_string(ptr, share->tgt_ssl_keys_lengths[link_idx]);
+    share->tgt_ssl_keys_lengths[0] = strlen(ptr);
+    share->tgt_ssl_keys[0] =
+      spider_create_string(ptr, share->tgt_ssl_keys_lengths[0]);
   } else {
-    share->tgt_ssl_keys_lengths[link_idx] = 0;
-    share->tgt_ssl_keys[link_idx] = NULL;
+    share->tgt_ssl_keys_lengths[0] = 0;
+    share->tgt_ssl_keys[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_SSL_VERIFY_SERVER_CERT_POS]->is_null() &&
     (ptr = get_field(mem_root,
       table->field[SPIDER_TABLES_SSL_VERIFY_SERVER_CERT_POS]))
   ) {
-    share->tgt_ssl_vscs[link_idx] = atol(ptr);
+    share->tgt_ssl_vscs[0] = atol(ptr);
   } else
-    share->tgt_ssl_vscs[link_idx] = -1;
+    share->tgt_ssl_vscs[0] = -1;
   if (
     !table->field[SPIDER_TABLES_MONITORING_BINLOG_POS_AT_FAILING_POS]->
       is_null() &&
     (ptr = get_field(mem_root, table->
       field[SPIDER_TABLES_MONITORING_BINLOG_POS_AT_FAILING_POS]))
   ) {
-    share->monitoring_binlog_pos_at_failing[link_idx] = atol(ptr);
+    share->monitoring_binlog_pos_at_failing[0] = atol(ptr);
   } else
-    share->monitoring_binlog_pos_at_failing[link_idx] = 0;
+    share->monitoring_binlog_pos_at_failing[0] = 0;
   if (
     !table->field[SPIDER_TABLES_DEFAULT_FILE_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_DEFAULT_FILE_POS]))
   ) {
-    share->tgt_default_files_lengths[link_idx] = strlen(ptr);
-    share->tgt_default_files[link_idx] =
-      spider_create_string(ptr, share->tgt_default_files_lengths[link_idx]);
+    share->tgt_default_files_lengths[0] = strlen(ptr);
+    share->tgt_default_files[0] =
+      spider_create_string(ptr, share->tgt_default_files_lengths[0]);
   } else {
-    share->tgt_default_files_lengths[link_idx] = 0;
-    share->tgt_default_files[link_idx] = NULL;
+    share->tgt_default_files_lengths[0] = 0;
+    share->tgt_default_files[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_DEFAULT_GROUP_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_DEFAULT_GROUP_POS]))
   ) {
-    share->tgt_default_groups_lengths[link_idx] = strlen(ptr);
-    share->tgt_default_groups[link_idx] =
-      spider_create_string(ptr, share->tgt_default_groups_lengths[link_idx]);
+    share->tgt_default_groups_lengths[0] = strlen(ptr);
+    share->tgt_default_groups[0] =
+      spider_create_string(ptr, share->tgt_default_groups_lengths[0]);
   } else {
-    share->tgt_default_groups_lengths[link_idx] = 0;
-    share->tgt_default_groups[link_idx] = NULL;
+    share->tgt_default_groups_lengths[0] = 0;
+    share->tgt_default_groups[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_DSN_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_DSN_POS]))
   ) {
-    share->tgt_dsns_lengths[link_idx] = strlen(ptr);
-    share->tgt_dsns[link_idx] =
-      spider_create_string(ptr, share->tgt_dsns_lengths[link_idx]);
+    share->tgt_dsns_lengths[0] = strlen(ptr);
+    share->tgt_dsns[0] =
+      spider_create_string(ptr, share->tgt_dsns_lengths[0]);
   } else {
-    share->tgt_dsns_lengths[link_idx] = 0;
-    share->tgt_dsns[link_idx] = NULL;
+    share->tgt_dsns_lengths[0] = 0;
+    share->tgt_dsns[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_FILEDSN_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_FILEDSN_POS]))
   ) {
-    share->tgt_filedsns_lengths[link_idx] = strlen(ptr);
-    share->tgt_filedsns[link_idx] =
-      spider_create_string(ptr, share->tgt_filedsns_lengths[link_idx]);
+    share->tgt_filedsns_lengths[0] = strlen(ptr);
+    share->tgt_filedsns[0] =
+      spider_create_string(ptr, share->tgt_filedsns_lengths[0]);
   } else {
-    share->tgt_filedsns_lengths[link_idx] = 0;
-    share->tgt_filedsns[link_idx] = NULL;
+    share->tgt_filedsns_lengths[0] = 0;
+    share->tgt_filedsns[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_DRIVER_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_DRIVER_POS]))
   ) {
-    share->tgt_drivers_lengths[link_idx] = strlen(ptr);
-    share->tgt_drivers[link_idx] =
-      spider_create_string(ptr, share->tgt_drivers_lengths[link_idx]);
+    share->tgt_drivers_lengths[0] = strlen(ptr);
+    share->tgt_drivers[0] =
+      spider_create_string(ptr, share->tgt_drivers_lengths[0]);
   } else {
-    share->tgt_drivers_lengths[link_idx] = 0;
-    share->tgt_drivers[link_idx] = NULL;
+    share->tgt_drivers_lengths[0] = 0;
+    share->tgt_drivers[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_TGT_DB_NAME_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_TGT_DB_NAME_POS]))
   ) {
-    share->tgt_dbs_lengths[link_idx] = strlen(ptr);
-    share->tgt_dbs[link_idx] =
-      spider_create_string(ptr, share->tgt_dbs_lengths[link_idx]);
+    share->tgt_dbs_lengths[0] = strlen(ptr);
+    share->tgt_dbs[0] =
+      spider_create_string(ptr, share->tgt_dbs_lengths[0]);
   } else {
-    share->tgt_dbs_lengths[link_idx] = 0;
-    share->tgt_dbs[link_idx] = NULL;
+    share->tgt_dbs_lengths[0] = 0;
+    share->tgt_dbs[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_TGT_TABLE_NAME_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_TGT_TABLE_NAME_POS]))
   ) {
-    share->tgt_table_names_lengths[link_idx] = strlen(ptr);
-    share->tgt_table_names[link_idx] =
-      spider_create_string(ptr, share->tgt_table_names_lengths[link_idx]);
+    share->tgt_table_names_lengths[0] = strlen(ptr);
+    share->tgt_table_names[0] =
+      spider_create_string(ptr, share->tgt_table_names_lengths[0]);
   } else {
-    share->tgt_table_names_lengths[link_idx] = 0;
-    share->tgt_table_names[link_idx] = NULL;
+    share->tgt_table_names_lengths[0] = 0;
+    share->tgt_table_names[0] = NULL;
   }
   if (
     !table->field[SPIDER_TABLES_STATIC_LINK_ID_POS]->is_null() &&
     (ptr = get_field(mem_root, table->field[SPIDER_TABLES_STATIC_LINK_ID_POS]))
   ) {
-    share->static_link_ids_lengths[link_idx] = strlen(ptr);
-    share->static_link_ids[link_idx] =
-      spider_create_string(ptr, share->static_link_ids_lengths[link_idx]);
+    share->static_link_ids_lengths[0] = strlen(ptr);
+    share->static_link_ids[0] =
+      spider_create_string(ptr, share->static_link_ids_lengths[0]);
   } else {
-    share->static_link_ids_lengths[link_idx] = 0;
-    share->static_link_ids[link_idx] = NULL;
+    share->static_link_ids_lengths[0] = 0;
+    share->static_link_ids[0] = NULL;
   }
   DBUG_RETURN(error_num);
 }

storage/spider/spd_table.cc

@@ -946,6 +946,7 @@ int spider_free_share_alloc(
   DBUG_RETURN(0);
 }
 
+/* Free a tmp_share, which has only one link */
 void spider_free_tmp_share_alloc(
   SPIDER_SHARE *share
 ) {
@@ -5892,6 +5893,7 @@ int spider_open_all_tables(
   THD *thd = trx->thd;
   TABLE *table_tables;
   int error_num, *need_mon, mon_val;
+  /* This share has only one link */
   SPIDER_SHARE tmp_share;
   char *db_name, *table_name;
   uint db_name_length, table_name_length;
@@ -5973,9 +5975,6 @@ int spider_open_all_tables(
         table_name_length
       )) ||
       (error_num = spider_create_conn_keys(&tmp_share)) ||
-/*
-      (error_num = spider_db_create_table_names_str(&tmp_share)) ||
-*/
       (error_num = spider_create_tmp_dbton_share(&tmp_share))
     ) {
       spider_sys_index_end(table_tables);
@@ -7367,6 +7366,10 @@ bool spider_check_pk_update(
   DBUG_RETURN(FALSE);
 }
 
+/*
+  Set fields of a tmp share which has only one link. For use in
+  monitoring, spider_copy_tables udf etc.
+*/
 void spider_set_tmp_share_pointer(
   SPIDER_SHARE *tmp_share,
   char **tmp_connect_info,

storage/spider/spd_trx.cc

@@ -2746,6 +2746,7 @@ int spider_internal_xa_rollback_by_xid(
   int error_num;
   char xa_key[MAX_KEY_LENGTH];
   char xa_member_key[MAX_KEY_LENGTH];
+  /* This share has only one link */
   SPIDER_SHARE tmp_share;
   char *tmp_connect_info[SPIDER_TMP_SHARE_CHAR_PTR_COUNT];
   uint tmp_connect_info_length[SPIDER_TMP_SHARE_UINT_COUNT];