From 73a7d99331d8fd0819fb9f7a10081e393590a94d Mon Sep 17 00:00:00 2001
From: Alexey Kopytov <Alexey.Kopytov@sun.com>
Date: Wed, 18 Mar 2009 11:18:24 +0300
Subject: Fix for bug#41486: extra character appears in BLOB for every         
           ~40Mb after mysqldump/import

When the input string exceeds the maximum allowed size for the
internal buffer, batch_readline() returns a truncated string.
Since there was no way for a caller to determine whether the
string was truncated or not, the command line client assumed
batch_readline() to always return the whole input string and
appended a newline character. This resulted in garbled data
when importing dumps containing strings longer than the
maximum input buffer size.

Fixed by adding a flag to the batch_readline() interface to
signal a truncated string to the caller.

Other minor problems fixed during patch implementation:

- The maximum allowed buffer size for batch_readline() was set
up depending on the client's max_allowed_packet value. It does
not actully make any sense, as those variables are not
related. The input buffer size limit is now always set to 1
MB.

- fill_buffer() did not always set the EOF flag.

- The input buffer could actually grow twice as the specified
limit due to insufficient checks in intern_read_line().

client/my_readline.h:
  Changed the interface of batch_readline().
client/mysql.cc:
  Honor the truncated flag returned by batch_readline() and do
  not append the newline character if it was set. Since we can't
  change the interfaces for readline()/fgets() used in the
  interactive mode, always assume the returned string was not
  truncated. In addition, always set the batch_readline()
  internal buffer to 1 MB, independently from the client's
  max_allowed_packet.
client/readline.cc:
  Added the 'truncated' argument do batch_readline() to signal
  truncated string to a caller.
  Fixed fill_buffer() to set the EOF flag correctly.
  Fixed checks in intern_read_line() to not allow the internal
  buffer grow past the specified limit.
mysql-test/r/mysql.result:
  Added a test case for bug #41486.
mysql-test/t/mysql.test:
  Added a test case for bug #41486.
---
 mysql-test/t/mysql.test | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

(limited to 'mysql-test/t/mysql.test')

diff --git a/mysql-test/t/mysql.test b/mysql-test/t/mysql.test
index 594d10e46a5..0030f624be6 100644
--- a/mysql-test/t/mysql.test
+++ b/mysql-test/t/mysql.test
@@ -331,4 +331,31 @@ EOF
 
 remove_file $MYSQLTEST_VARDIR/tmp/bug31060.sql;
 
+#  
+# Bug #41486: extra character appears in BLOB for every ~40Mb after   
+#             mysqldump/import   
+#  
+  
+# Have to change the global variable as the mysql client will use 
+# a separate session 
+set @old_max_allowed_packet = @@global.max_allowed_packet; 
+# 2 MB blob length + some space for the rest of INSERT query
+set @@global.max_allowed_packet = 2 * 1024 * 1024 + 1024; 
+set @@max_allowed_packet = @@global.max_allowed_packet;
+
+CREATE TABLE t1(data LONGBLOB);  
+INSERT INTO t1 SELECT REPEAT('1', 2*1024*1024);  
+  
+--exec $MYSQL_DUMP test t1 >$MYSQLTEST_VARDIR/tmp/bug41486.sql  
+# Check that the mysql client does not insert extra newlines when loading  
+# strings longer than client's max_allowed_packet  
+--exec $MYSQL --max_allowed_packet=1M test < $MYSQLTEST_VARDIR/tmp/bug41486.sql 2>&1  
+SELECT LENGTH(data) FROM t1;  
+  
+remove_file $MYSQLTEST_VARDIR/tmp/bug41486.sql; 
+DROP TABLE t1;  
+
+set @@global.max_allowed_packet = @old_max_allowed_packet; 
+set @@max_allowed_packet = @@global.max_allowed_packet;
+ 
 --echo End of 5.0 tests
-- 
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