All Questions(server)

Every time I try to make a mysqldump I get the following error:

$> mysqldump --single-transaction --host host -u user -p db > db.sql
mysqldump: Couldn't execute 'SELECT COLUMN_NAME, JSON_EXTRACT(HISTOGRAM,
'$."number-of-buckets-specified"') FROM
information_schema.COLUMN_STATISTICS WHERE SCHEMA_NAME = 'db' AND
TABLE_NAME = 'Absence';':
Unknown table 'COLUMN_STATISTICS' in information_schema (1109)

The result is a dump which is not complete. The strange thing is that the same command, executed from another host, works without throwing any errors. Did someone experienced the same problem?

I'm using mysql-client 8.0 and try to access a mysql 5-7 server - maybe that is the reason?

The other day, we notice a terrible burning smell coming out of the server room. Long story short, it ended up being one of the battery modules that was burning up in the UPS unit, but it took a good couple of hours before we were able to figure it out. The main reason we were able to figure it out is that the UPS display finally showed that the module needed to be replaced.

Here was the problem: the whole room was filled with the smell. Doing a sniff test was very difficult because the smell had infiltrated everything (not to mention it made us light headed). We almost mistakenly took our production database server down because it's where the smell was the strongest. The vitals appeared to be ok (CPU temps showed 60 degrees C, and fan speeds ok), but we weren't sure. It just so happened that the battery module that burnt up was about the same height as the server on the rack and only 3 ft away. Had this been a real emergency, we would have failed miserably.

Realistically, the chances that actual server hardware is burning up is a fairly rare occurrence and most of the time we'll be looking at the UPS the culprit. But with several racks with several pieces of equipment, it can quickly become a guessing game. How does one quickly and accurately determine what piece of equipment is actually burning up? I realize this question is highly dependent on the environment variables such as room size, ventilation, location, etc, but any input would be appreciated.

I have Googled about a solution for quite some time, but couldn't find an answer.

I am on Ubuntu Linux and want to run a server on port 80, but due to security mechanism of Ubuntu, I get the following error:

java.net.BindException: Permission denied:80

I think it should be simple enough to either disable this security mechanism so that port 80 is available to all users or to assign required privileges to the current user to access port 80.

I have just installed postgres 8.4 on Ubuntu 9.10 and it has never asked me to create a superuser. Is there a default superuser and its password? If not, how do I create a new one?

I have an existing public/private key pair. The private key is password protected, and the encryption may be either RSA or DSA. These keys are the kind you generate with ssh-keygen and generally store under ~/.ssh.

I'd like to change the private key's password. How do I go about it, on a standard Unix shell?

Also, how do I simply remove the password? Just change it to empty?