mySQL memory engine : is max nrows 2^32? -

it seems maximum number of rows mysql memory engine table can have 2^32 - 1. worryingly, when add 1 more row, table becomes empty.

is known behaviour (it's not documented in manual), or doing wrong when create table ?

i'm using out of box mysql server ver 14.14 distrib 5.5.57, on r4.16xlarge aws instance. don't observe such limit myisam / innodb tables.

mysql> select count(*) big_ram ; +------------+ | count(*)   | +------------+ | 4294967295 | +------------+ 1 row in set (0.00 sec)  mysql> insert big_ram values ('aaaa','bbbb') ; query ok, 1 row affected (0.00 sec)  mysql> select count(*) big_ram ; +----------+ | count(*) | +----------+ |        0 | +----------+ 1 row in set (0.00 sec)  mysql> select * big_ram limit 10 ; empty set (0.00 sec) 

the table created , populated statement. interestingly, 'show table status' reports 'create_options: min_rows=4294967295'

create table big_ram (     s1 char(4)     , s2 char(4) ) min_rows=5000000000 , engine=memory ;  load data local infile '/ramdisk/data.csv'     table big_ram     fields terminated ','      lines terminated '\n'       (s1,s2) ; 

for interested or willing replicate behaviour, big csv file created bash script (in couple of minutes if you're using ramdisk):

df1=/ramdisk/data.csv df2=/ramdisk/data2.csv  # number of lines 2^p : 32 gives 4g rows p=32   cat > ${df1} <<- eof     abcd,defg     abcd,defg eof  n=2 in $(seq 2 ${p})      cat ${df1} ${df1} > ${df2} && mv ${df2} ${df1};      n=$(( n * 2 ))     fs=$( du -h ${df1} | cut -f1 )     echo "$i : $fs : $n lines : in ${seconds} secs" done  # remove couple of lines sed -i -e '1,5d' ${df1}