Commit e60c8c8b authored by Staale Smedseng's avatar Staale Smedseng
Browse files

A fix for Bug#22891 "session level max_allowed_packet can be 

set but is ignored".
                                  
This patch makes @@session.max_allowed_packed and
@@session.net_buffer_length read-only as suggested in the bug
report. The user will have to use SET GLOBAL (and reconnect)
to alter the session values of these variables.
                            
The error string ER_VARIABLE_IS_READONLY is introduced.
                            
Tests are modified accordingly.
parent b8cd1725

mysql-test/r/func_compress.result

+1 −1
Original line number Diff line number Diff line
@@ -68,7 +68,7 @@ Warnings: 
Error	1259	ZLIB: Input data corrupted

Error	1256	Uncompressed data size too large; the maximum size is 1048576 (probably, length of uncompressed data was corrupted)

drop table t1;

set @@max_allowed_packet=1048576*100;

set @@global.max_allowed_packet=1048576*100;

select compress(repeat('aaaaaaaaaa', IF(XXX, 10, 10000000))) is null;

compress(repeat('aaaaaaaaaa', IF(XXX, 10, 10000000))) is null

0

mysql-test/r/max_allowed_packet_basic.result

+25 −28
Original line number Diff line number Diff line
@@ -2,10 +2,7 @@ SET @start_global_value = @@global.max_allowed_packet; 
SELECT @start_global_value;

@start_global_value

1048576

SET @start_session_value = @@session.max_allowed_packet;

SELECT @start_session_value;

@start_session_value

1048576

SET @@global.max_allowed_packet = DEFAULT;

'#--------------------FN_DYNVARS_070_01-------------------------#'

SET @@global.max_allowed_packet = 1000;

Warnings:
@@ -15,7 +12,9 @@ SELECT @@global.max_allowed_packet; 
@@global.max_allowed_packet

1048576

SET @@session.max_allowed_packet = 20000;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SET @@session.max_allowed_packet = DEFAULT;

ERROR 42000: Variable 'max_allowed_packet' doesn't have a default value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1048576
@@ -24,10 +23,6 @@ SET @@global.max_allowed_packet = DEFAULT; 
SELECT @@global.max_allowed_packet = 1048576;

@@global.max_allowed_packet = 1048576

1

SET @@session.max_allowed_packet = DEFAULT;

SELECT @@session.max_allowed_packet = 1048576;

@@session.max_allowed_packet = 1048576

1

'#--------------------FN_DYNVARS_070_03-------------------------#'

SET @@global.max_allowed_packet = 1024;

SELECT @@global.max_allowed_packet;
@@ -48,25 +43,30 @@ SELECT @@global.max_allowed_packet; 
1073740800

'#--------------------FN_DYNVARS_070_04-------------------------#'

SET @@session.max_allowed_packet = 1024;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1024

1048576

SET @@session.max_allowed_packet = 1025;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1024

1048576

SET @@session.max_allowed_packet = 65535;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

64512

1048576

SET @@session.max_allowed_packet = 1073741824;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1073741824

1048576

SET @@session.max_allowed_packet = 1073741823;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1073740800

1048576

'#------------------FN_DYNVARS_070_05-----------------------#'

SET @@global.max_allowed_packet = 0;

Warnings:
@@ -103,37 +103,33 @@ SELECT @@global.max_allowed_packet; 
@@global.max_allowed_packet

1073741824

SET @@session.max_allowed_packet = 0;

Warnings:

Warning	1292	Truncated incorrect max_allowed_packet value: '0'

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1024

1048576

SET @@session.max_allowed_packet = 1023;

Warnings:

Warning	1292	Truncated incorrect max_allowed_packet value: '1023'

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1024

1048576

SET @@session.max_allowed_packet = -2;

Warnings:

Warning	1292	Truncated incorrect max_allowed_packet value: '0'

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1024

1048576

SET @@session.max_allowed_packet = 65530.34.;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.' at line 1

SET @@session.max_allowed_packet = 10737418241;

Warnings:

Warning	1292	Truncated incorrect max_allowed_packet value: '10737418241'

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1073741824

1048576

'Bug # 34837: Errors are not coming on assigning invalid values to variable';

SET @@session.max_allowed_packet = test;

ERROR 42000: Incorrect argument type to variable 'max_allowed_packet'

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1073741824

1048576

'#------------------FN_DYNVARS_070_06-----------------------#'

SELECT @@global.max_allowed_packet = VARIABLE_VALUE 

FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
@@ -166,6 +162,7 @@ SELECT @@max_allowed_packet = @@global.max_allowed_packet; 
0

'#---------------------FN_DYNVARS_070_10----------------------#'

SET @@max_allowed_packet = 100000;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@max_allowed_packet = @@local.max_allowed_packet;

@@max_allowed_packet = @@local.max_allowed_packet

1
@@ -174,9 +171,10 @@ SELECT @@local.max_allowed_packet = @@session.max_allowed_packet; 
1

'#---------------------FN_DYNVARS_070_11----------------------#'

SET max_allowed_packet = 1024;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@max_allowed_packet;

@@max_allowed_packet

1024

1048576

SELECT local.max_allowed_packet;

ERROR 42S02: Unknown table 'local' in field list

SELECT session.max_allowed_packet;
@@ -187,7 +185,6 @@ SET @@global.max_allowed_packet = @start_global_value; 
SELECT @@global.max_allowed_packet;

@@global.max_allowed_packet

1048576

SET @@session.max_allowed_packet = @start_session_value;

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1048576

mysql-test/r/max_allowed_packet_func.result

+5 −14
Original line number Diff line number Diff line
@@ -10,24 +10,15 @@ name BLOB 
'#--------------------FN_DYNVARS_070_01-------------------------#'

## Setting value of max_allowed packet and net_buffer_length to 1024 ## 

SET @@session.max_allowed_packet = 1024;

SET @@session.net_buffer_length = 1024;

ERROR HY000: SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.max_allowed_packet;

@@session.max_allowed_packet

1024

1048576

SET @@session.net_buffer_length = 1024;

ERROR HY000: SESSION variable 'net_buffer_length' is read-only. Use SET GLOBAL to assign the value

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1024

## Inserting and fetching data of length greater than 1024 ##

INSERT into t1(name) values("aaassssssssddddddddffffffgggggggg, askdlfjalsdkjfalksdjflaksdjfalkjdflaksjdflakjdflajsflajflajdfalsjfdlajfladjslfajdflajdsflajsflakjsdfla;kjflsdjkf;aljfa;lkdsfjla;sjlkajffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllakjsdffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffa;;;;;;;;;;;;;;;;;;;;;;;;;;;dsklfjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjkljffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffdkskkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk");

SELECT length("aaaaaasssssssssssdddddddfffffgggg, askdlfjalsdkjfalksdjflaksdjfalkjdflaksjdflakjdflajsflajflajdfalsjfdlajfladjslfajdflajdsflajsflakjsdfla;kjflsdjkf;aljfa;lkdsfjla;sjlkajffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllakjsdffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffa;;;;;;;;;;;;;;;;;;;;;;;;;;;dsklfjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjkljffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffdkskkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk") as len;

len

1470

## Verifying record in table t1 ##

SELECT * from t1;

id	name

1	aaassssssssddddddddffffffgggggggg, askdlfjalsdkjfalksdjflaksdjfalkjdflaksjdflakjdflajsflajflajdfalsjfdlajfladjslfajdflajdsflajsflakjsdfla;kjflsdjkf;aljfa;lkdsfjla;sjlkajffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllakjsdffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffa;;;;;;;;;;;;;;;;;;;;;;;;;;;dsklfjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjkljffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffdkskkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk

'Bug#35381: Error is not coming on inserting and fetching data of length'

'greater than max_allowed_packet size at session level';

16384

'#--------------------FN_DYNVARS_070_02-------------------------#'

## Setting value of max_allowed packet and net_buffer_length to 1024 ## 

SET @@global.max_allowed_packet = 1024;

mysql-test/r/net_buffer_length_basic.result

+5 −67
Original line number Diff line number Diff line 
SET @start_global_value = @@global.net_buffer_length;

SET @start_session_value = @@session.net_buffer_length;

SET @@global.net_buffer_length = DEFAULT;

'#--------------------FN_DYNVARS_109_01-------------------------#'

SET @@global.net_buffer_length = 10000;

SET @@global.net_buffer_length = DEFAULT;
@@ -7,7 +7,9 @@ SELECT @@global.net_buffer_length; 
@@global.net_buffer_length

16384

SET @@session.net_buffer_length = 20000;

ERROR HY000: SESSION variable 'net_buffer_length' is read-only. Use SET GLOBAL to assign the value

SET @@session.net_buffer_length = DEFAULT;

ERROR 42000: Variable 'net_buffer_length' doesn't have a default value

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

16384
@@ -16,10 +18,6 @@ SET @@global.net_buffer_length = DEFAULT; 
SELECT @@global.net_buffer_length = 16384;

@@global.net_buffer_length = 16384

1

SET @@session.net_buffer_length = DEFAULT;

SELECT @@session.net_buffer_length = 16384;

@@session.net_buffer_length = 16384

1

'#--------------------FN_DYNVARS_109_03-------------------------#'

SET @@global.net_buffer_length = 1024;

SELECT @@global.net_buffer_length;
@@ -43,27 +41,6 @@ SELECT @@global.net_buffer_length; 
64512

'Bug# 34877: Invalid Values are coming in variable on assigning valid values';

'#--------------------FN_DYNVARS_109_04-------------------------#'

SET @@session.net_buffer_length = 1024;

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1024

SET @@session.net_buffer_length = 1025;

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1024

SET @@session.net_buffer_length = 1048576;

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1048576

SET @@session.net_buffer_length = 1048575;

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1047552

SET @@session.net_buffer_length = 65535;

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

64512

'Bug# 34877: Invalid Values are coming in variable on assigning valid values';

'#------------------FN_DYNVARS_109_05-----------------------#'

SET @@global.net_buffer_length = 0;

Warnings:
@@ -105,42 +82,12 @@ ERROR 42000: Incorrect argument type to variable 'net_buffer_length' 
SELECT @@global.net_buffer_length;

@@global.net_buffer_length

1048576

SET @@session.net_buffer_length = 0;

Warnings:

Warning	1292	Truncated incorrect net_buffer_length value: '0'

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1024

SET @@session.net_buffer_length = -2;

Warnings:

Warning	1292	Truncated incorrect net_buffer_length value: '0'

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1024

SET @@session.net_buffer_length = 1048577;

Warnings:

Warning	1292	Truncated incorrect net_buffer_length value: '1048577'

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1048576

SET @@session.net_buffer_length = 1048576002;

Warnings:

Warning	1292	Truncated incorrect net_buffer_length value: '1048576002'

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

1048576

SET @@session.net_buffer_length = 65530.34.;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.' at line 1

SET @@session.net_buffer_length = 65550;

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

65536

'Bug # 34837: Errors are not coming on assigning invalid values to variable';

SET @@session.net_buffer_length = test;

ERROR 42000: Incorrect argument type to variable 'net_buffer_length'

SELECT @@session.net_buffer_length;

@@session.net_buffer_length

65536

16384

'#------------------FN_DYNVARS_109_06-----------------------#'

SELECT @@global.net_buffer_length = VARIABLE_VALUE 

FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
@@ -172,18 +119,10 @@ SELECT @@net_buffer_length = @@global.net_buffer_length; 
@@net_buffer_length = @@global.net_buffer_length

0

'#---------------------FN_DYNVARS_109_10----------------------#'

SET @@net_buffer_length = 100000;

SELECT @@net_buffer_length = @@local.net_buffer_length;

@@net_buffer_length = @@local.net_buffer_length

1

SELECT @@local.net_buffer_length = @@session.net_buffer_length;

@@local.net_buffer_length = @@session.net_buffer_length

1

'#---------------------FN_DYNVARS_109_11----------------------#'

SET net_buffer_length = 1024;

SELECT @@net_buffer_length;

@@net_buffer_length

1024

16384

SELECT local.net_buffer_length;

ERROR 42S02: Unknown table 'local' in field list

SELECT session.net_buffer_length;
@@ -191,4 +130,3 @@ ERROR 42S02: Unknown table 'session' in field list 
SELECT net_buffer_length = @@session.net_buffer_length;

ERROR 42S22: Unknown column 'net_buffer_length' in 'field list'

SET @@global.net_buffer_length = @start_global_value;
 
SET @@session.net_buffer_length = @start_session_value;

mysql-test/r/packet.result

+1 −11
Original line number Diff line number Diff line 
set global max_allowed_packet=100;

Warnings:

Warning	1292	Truncated incorrect max_allowed_packet value: '100'

set max_allowed_packet=100;

Warnings:

Warning	1292	Truncated incorrect max_allowed_packet value: '100'

set global net_buffer_length=100;

Warnings:

Warning	1292	Truncated incorrect net_buffer_length value: '100'

set net_buffer_length=100;

Warnings:

Warning	1292	Truncated incorrect net_buffer_length value: '100'

SELECT length("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") as len;

len

1024

select repeat('a',2000);

repeat('a',2000)

NULL

Warnings:

Warning	1301	Result of repeat() was larger than max_allowed_packet (1024) - truncated

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

select @@net_buffer_length, @@max_allowed_packet;

@@net_buffer_length	@@max_allowed_packet

1024	1024

SELECT length("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") as len;

ERROR 08S01: Got a packet bigger than 'max_allowed_packet' bytes

set global max_allowed_packet=default;

set max_allowed_packet=default;

set global net_buffer_length=default;

set net_buffer_length=default;

SELECT length("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") as len;

len

100