set session transaction_prealloc_size=1024*1024*1024*1;
show processlist;
Id	User	Host	db	Command	Time	State	Info
6	root	localhost	test	Query	0	NULL	show processlist
set session transaction_prealloc_size=1024*1024*1024*2;
show processlist;
Id	User	Host	db	Command	Time	State	Info
6	root	localhost	test	Query	1	NULL	show processlist
set session transaction_prealloc_size=1024*1024*1024*3;
show processlist;
Id	User	Host	db	Command	Time	State	Info
6	root	localhost	test	Query	0	NULL	show processlist
set session transaction_prealloc_size=1024*1024*1024*4;
Warnings:
Warning	1292	Truncated incorrect transaction_prealloc_size value: '4294967296'
show processlist;
Id	User	Host	db	Command	Time	State	Info
6	root	localhost	test	Query	0	NULL	show processlist
set session transaction_prealloc_size=1024*1024*1024*5;
Warnings:
Warning	1292	Truncated incorrect transaction_prealloc_size value: '5368709120'
show processlist;
Id	User	Host	db	Command	Time	State	Info
6	root	localhost	test	Query	0	NULL	show processlist