Bonjour,
MW> MySQL does use the gzip algorithm for the compression. The difference
MW> is that MYSQL does a separate gzip for each package to keep things
MW> safe.
MW> You can get better compression simply by increasing the
MW> 'max_allowed_packet' variable in your client.
In fact, most of the file which are uploaded to the Mysql table are
about 45ko. The biggest are about 400ko. And I found on the
documentation :
"The client's default maximum is 24M, but the default maximum in the
server is 1M."
So I suppose that all the file is sent in one time and that the
compression should already by maximum isn't it ?
MW> Have you checked that client/server protocol is really compressed?
MW> (In other words: Are you sure your server and client both are
MW> compiled with compression ?)
Server compiled with compression ? I didn't see that option in
./configure --help .
Both the server and the client are 3.22.21. I thought compression
was by default allowed by server and on the demand using
CLIENT_COMPRESS with mysql_real_connect() in the client. Isn't it ?
MW> MySQL inserts the rows at the same time it gets them; In other words,
MW> your other clients are locked during the whole transfer.
Waou. That sounds really horrible for my solution. In fact I have
about 4 little programs which are continuously updating a remote
table with some quotation updates (about once per minute for each
program taking the quotations from little text files which are well
designed for LOAD DATA command). And on the server side, we have
many web sites which are querying the Mysql quotation database (a
lot of select with joins ...). This solution can't suffer of a to
long lock delay while inserting the updates.
Isn't there a simple way to add an option which would tell the
server to do the insert into the table only once it has received all
the data (for LOAD DATA _LOCAL_) ?
If for example someone uses LOAD DATA LOCAL in order to update a
remote table with large files on a slow network, the delay while all
SELECT on this table will be locked may be a REAL problem. Don't you
agree ?
On my own, yesterday I reached for the first time the
max_connections of 256 which I configured on the server and I
was really surprised. But now I know why ! with the table being
SELECT locked for 3-4 seconds due to the network transfer delay, the
number of clients locked is rapidly increasing.
Yours,
Alex
