[Maria-developers] More Secure Kill Command
Hi guys i was mailing at maria-discuss, but i think it a new feature, and want some view point from developers... check this problem: connection 1) big select... connection 2) show processlist connection 1) other query connection 2) kill connection 1 id (i take +- 1 second between show processlist and this command) connection 1) killed the problem? the kill connection 1 (KILL thread_id) killed the wrong query could we implement something like: KILL [CONNECTION | QUERY] thread_id [QUERY "some relative unique query id in this database"] the relative unique query id, could be: substr(sha1 or md5 of (thread_id + query start time),0,6) (6 hex numbers is good?) it's like a git small hash commit id, maybe we could make it more unique... but since i will not use it very often, i think a less intensive work is nice here... a global query id could add more one lock for every query... example: KILL 1 QUERY "abcdef" the "abcdef" = substr(MD5( thread id + query start time ),0,6) we could add client ip or others unique information about this query, but something that don't increase (ok just a little) the load of a show processlist / select * from information_schema thanks -- Roberto Spadim
As part of adding per query table/index statistics I added a per
thread query_id. This would serve your purpose too. You could do kill
connection_id query_id and be guaranteed of killing the query you want
on a specific connection.
On Fri, Aug 16, 2013 at 2:31 PM, Roberto Spadim
Hi guys i was mailing at maria-discuss, but i think it a new feature, and want some view point from developers... check this problem:
connection 1) big select... connection 2) show processlist connection 1) other query connection 2) kill connection 1 id (i take +- 1 second between show processlist and this command) connection 1) killed
the problem? the kill connection 1 (KILL thread_id) killed the wrong query could we implement something like:
KILL [CONNECTION | QUERY] thread_id [QUERY "some relative unique query id in this database"]
the relative unique query id, could be: substr(sha1 or md5 of (thread_id + query start time),0,6) (6 hex numbers is good?) it's like a git small hash commit id, maybe we could make it more unique... but since i will not use it very often, i think a less intensive work is nice here... a global query id could add more one lock for every query...
example: KILL 1 QUERY "abcdef"
the "abcdef" = substr(MD5( thread id + query start time ),0,6)
we could add client ip or others unique information about this query, but something that don't increase (ok just a little) the load of a show processlist / select * from information_schema
thanks
-- Roberto Spadim
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-- Eric Bergen eric.bergen@gmail.com http://www.ebergen.net
Hi, Eric! On Aug 16, Eric Bergen wrote:
As part of adding per query table/index statistics I added a per thread query_id. This would serve your purpose too. You could do kill connection_id query_id and be guaranteed of killing the query you want on a specific connection.
Yes, my thought exactly. It'd be pretty easy to extend KILL to support killing by query_id, not by thread_id. Regards, Sergei
yeah i liked this idea about query_id too...
thread_id + query_id is a nice solution (at least i think it will work)
i was considering query start time too, but since kill isn't a command with
very high frequency (kills/second), the query_id could solve the problem
nicely
the only problem i can see is: if thread id is low (example connection id =
50), and we have a server restart and at the same thread id (50), runs the
same number of queries...
well the probability is very very small... at least i think it is, and if
we execute the KILL, we will get a connection lost from server... and we
should execute the show processlist again...
if we don't want the show processlist again, just add the query start time
(YYYY-MM-DD HH:MM:SS), but for the first implementation query id is
nice...
the query_id is currently implemented? or should be implemented? sorry i'm
asking without reading the source code ...
about syntax, should it be
KILL
Sorry Sergei i didn't read your email before sending more one...
"Yes, my thought exactly. It'd be pretty easy to extend KILL to support
killing by query_id, not by thread_id."
some points that i think important...
the "KILL [QUERY | CONNECTION]
Hi, Roberto! On Aug 17, Roberto Spadim wrote:
yeah i liked this idea about query_id too...
the query_id is currently implemented? or should be implemented? sorry i'm asking without reading the source code ...
It is implemented. Currently, KILL works like (kill_one_thread function) while ((tmp=it++)) if (tmp->thread_id == id) break; to kill by query id, it should be simply while ((tmp=it++)) if (tmp->query_id == id) break; And some safety checks, of course. Not really a one-line change, but close.
about syntax, should it be KILL
or KILL QUERY <query id> ?
I don't have a good one. May be KILL QUERY ID nnn ? So that the full syntax would be KILL [ CONNECTION | QUERY [ ID ] ] nnn; Regards, Sergei
PEBKAC... If you want more safety then make a script like molly-guard that will ask you to confirm the kill command you want to execute to avoid mistakes. Le 16/08/2013 23:31, Roberto Spadim a écrit :
Hi guys i was mailing at maria-discuss, but i think it a new feature, and want some view point from developers... check this problem:
connection 1) big select... connection 2) show processlist connection 1) other query connection 2) kill connection 1 id (i take +- 1 second between show processlist and this command) connection 1) killed
the problem? the kill connection 1 (KILL thread_id) killed the wrong query could we implement something like:
KILL [CONNECTION | QUERY] thread_id [QUERY "some relative unique query id in this database"]
the relative unique query id, could be: substr(sha1 or md5 of (thread_id + query start time),0,6) (6 hex numbers is good?) it's like a git small hash commit id, maybe we could make it more unique... but since i will not use it very often, i think a less intensive work is nice here... a global query id could add more one lock for every query...
example: KILL 1 QUERY "abcdef"
the "abcdef" = substr(MD5( thread id + query start time ),0,6)
we could add client ip or others unique information about this query, but something that don't increase (ok just a little) the load of a show processlist / select * from information_schema
thanks
hi!
i think it too complex.. i should send two SQL command!?
i already know what thread and what query i want to kill... why should i
send it twice?
2013/8/17 Jean Weisbuch
PEBKAC...
If you want more safety then make a script like molly-guard that will ask you to confirm the kill command you want to execute to avoid mistakes.
Le 16/08/2013 23:31, Roberto Spadim a écrit :
Hi guys i was mailing at maria-discuss, but i think it a new feature, and want some view point from developers... check this problem:
connection 1) big select... connection 2) show processlist connection 1) other query connection 2) kill connection 1 id (i take +- 1 second between show processlist and this command) connection 1) killed
the problem? the kill connection 1 (KILL thread_id) killed the wrong query could we implement something like:
KILL [CONNECTION | QUERY] thread_id [QUERY "some relative unique query id in this database"]
the relative unique query id, could be: substr(sha1 or md5 of (thread_id + query start time),0,6) (6 hex numbers is good?) it's like a git small hash commit id, maybe we could make it more unique... but since i will not use it very often, i think a less intensive work is nice here... a global query id could add more one lock for every query...
example: KILL 1 QUERY "abcdef"
the "abcdef" = substr(MD5( thread id + query start time ),0,6)
we could add client ip or others unique information about this query, but something that don't increase (ok just a little) the load of a show processlist / select * from information_schema
thanks
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-- Roberto Spadim SPAEmpresarial
participants (4)
-
Eric Bergen -
Jean Weisbuch -
Roberto Spadim -
Sergei Golubchik