MDEV-14637: Fix hang due to persistent statistics

Similar to the tables SYS_FOREIGN and SYS_FOREIGN_COLS,
the tables mysql.innodb_table_stats and mysql.innodb_index_stats
are updated by the InnoDB internal SQL parser, which fails to
enforce the size limits of the data. Due to this, it is possible
for InnoDB to hang when there are persistent statistics defined on
partitioned tables where the total length of table name,
partition name and subpartition name exceeds the incorrectly
defined limit VARCHAR(64). That column should have been defined
as VARCHAR(199).

btr_node_ptr_max_size(): Interpret the VARCHAR(64) as VARCHAR(199),
to prevent a hang in the case that the upgrade script has not been
run.

dict_table_schema_check(): Ignore difference in the length of the
table_name column.

ha_innobase::max_supported_key_length(): For innodb_page_size=4k,
return a larger value so that the table mysql.innodb_index_stats
can be created. This could allow "impossible" tables to be created,
such that it is not possible to insert anything into a secondary
index when both the secondary key and the primary key are long,
but this is the easiest and most consistent way. The Oracle fix
would only ignore the maximum length violation for the two
statistics tables.

os_file_get_status_posix(), os_file_get_status_win32(): Handle
ENAMETOOLONG as well.

This patch is based on the following change in MySQL 5.7.23.
Not all changes were applied, and our variant allows persistent
statistics to work without hangs even if the table definitions
were not upgraded.

From fdbdce701ab8145ae234c9d401109dff4e4106cb Mon Sep 17 00:00:00 2001
From: Aditya A <aditya.a@oracle.com>
Date: Thu, 17 May 2018 16:11:43 +0530
Subject: [PATCH] Bug #26390736 THE FIELD TABLE_NAME (VARCHAR(64)) FROM
           MYSQL.INNODB_TABLE_STATS CAN OVERFLOW.

    In mysql.innodb_index_stats and mysql.innodb_table_stats
    tables the table name column didn't take into consideration
    partition names which can be more than varchar(64).

2 files changed, 6 insertions, 6 deletions

diff --git a/scripts/mysql_system_tables.sql b/scripts/mysql_system_tables.sql
index 7b614163f46..c5792168213 100644
--- a/scripts/mysql_system_tables.sql
+++ b/scripts/mysql_system_tables.sql
@@ -1,4 +1,4 @@
--- Copyright (c) 2007, 2013, Oracle and/or its affiliates.
+-- Copyright (c) 2007, 2018, Oracle and/or its affiliates.
 -- Copyright (c) 2008, 2014, Monty Program Ab & SkySQL Ab
 -- 
 -- This program is free software; you can redistribute it and/or modify
@@ -105,7 +105,7 @@ CREATE TABLE IF NOT EXISTS event ( db char(64) CHARACTER SET utf8 COLLATE utf8_b
 
 SET @create_innodb_table_stats="CREATE TABLE IF NOT EXISTS innodb_table_stats (
 	database_name			VARCHAR(64) NOT NULL,
-	table_name			VARCHAR(64) NOT NULL,
+	table_name			VARCHAR(199) NOT NULL,
 	last_update			TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
 	n_rows				BIGINT UNSIGNED NOT NULL,
 	clustered_index_size		BIGINT UNSIGNED NOT NULL,
@@ -115,7 +115,7 @@ SET @create_innodb_table_stats="CREATE TABLE IF NOT EXISTS innodb_table_stats (
 
 SET @create_innodb_index_stats="CREATE TABLE IF NOT EXISTS innodb_index_stats (
 	database_name			VARCHAR(64) NOT NULL,
-	table_name			VARCHAR(64) NOT NULL,
+	table_name			VARCHAR(199) NOT NULL,
 	index_name			VARCHAR(64) NOT NULL,
 	last_update			TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
 	/* there are at least:
diff --git a/scripts/mysql_system_tables_fix.sql b/scripts/mysql_system_tables_fix.sql
index e724c3e2d23..db32834c4d6 100644
--- a/scripts/mysql_system_tables_fix.sql
+++ b/scripts/mysql_system_tables_fix.sql
@@ -697,13 +697,13 @@ set @str=replace(@str, "innodb_index_stats", "innodb_table_stats");
 prepare stmt from @str;
 execute stmt;
 
-# update timestamp fields in the innodb stat tables
-set @str="alter table mysql.innodb_index_stats modify last_update timestamp not null default current_timestamp on update current_timestamp";
+# update table_name and timestamp fields in the innodb stat tables
+set @str="alter table mysql.innodb_index_stats modify last_update timestamp not null default current_timestamp on update current_timestamp, modify table_name varchar(199)";
 set @str=if(@have_innodb <> 0, @str, "set @dummy = 0");
 prepare stmt from @str;
 execute stmt;
 
-set @str="alter table mysql.innodb_table_stats modify last_update timestamp not null default current_timestamp on update current_timestamp";
+set @str="alter table mysql.innodb_table_stats modify last_update timestamp not null default current_timestamp on update current_timestamp, modify table_name varchar(199)";
 set @str=if(@have_innodb <> 0, @str, "set @dummy = 0");
 prepare stmt from @str;
 execute stmt;