MySQL Bugs: #7928: out of connection objects

Bug #7928	out of connection objects
Submitted:	15 Jan 2005 16:25	Modified:	20 Jan 2005 12:45
Reporter:	frank homann
Status:	Closed
Category:	Server: Cluster	Severity:	S3 (Non-critical)
Version:	4.1.9	OS:	Linux (linux-2.6.10)
Assigned to:	Jonas Oreland	Target Version:

Description:
we are testing a 3 nodes mysql cluster:

Cluster Configuration
---------------------
[ndbd(NDB)]     2 node(s)
id=2 (not connected, accepting connect from 10.0.91.119)
id=3    @10.0.91.120  (Version: 4.1.9, Nodegroup: 0, Master)

[ndb_mgmd(MGM)] 1 node(s)
id=1    @10.0.91.118  (Version: 4.1.9)

[mysqld(API)]   3 node(s)
id=4    @10.0.91.120  (Version: 4.1.9)
id=5    @10.0.91.119  (Version: 4.1.9)
id=6    @10.0.91.118  (Version: 4.1.9)

with a phpadsnew installation and after ~300k banner impressions the cluster stops
working with this error:

ERROR 1297 (HY000): Got temporary error 4006 'Connect failure - out of connection objects
(increase MaxNoOfConcurrentTransactions)' from ndbcluster

and it's recoverable only by restarting the ndbd nodes...

during the tests there are ~400 queries/second on every node and the servers load keeps
below 5.

we've tried increasing both MaxNoOfConcurrentOperations and MaxNoOfConcurrentTransactions
until 1258291 and 157286 respectively (above these values ndbd doesn't come up)

as suggested from Mikael Ronström (mikael@mysql.com) we have even tried to run ndbd with
the --skip-ndb-optimized-node-selection command line option but with the same result...

even setting TransactionInactiveTimeout = 5000 doesn't solve the issue...

thank you!

How to repeat:
install phpadsnew with a mysql cluster as backend and stress it with ApacheBench

configuration:

[NDBD DEFAULT]
NoOfReplicas = 2
[MYSQLD DEFAULT]
[NDB_MGMD DEFAULT]
[TCP DEFAULT]
# Managment Server
[NDB_MGMD]
HostName = 10.0.91.118            # the IP of THIS SERVER
# Storage Engines
[NDBD]
HostName = 10.0.91.119            # the IP of the FIRST SERVER
DataDir = /var/lib/mysql
MaxNoOfConcurrentOperations = 1258291
MaxNoOfConcurrentTransactions = 157286
TransactionInactiveTimeout = 5000
[NDBD]
HostName = 10.0.91.120            # the IP of the SECOND SERVER
DataDir = /var/lib/mysql
MaxNoOfConcurrentOperations = 1258291
MaxNoOfConcurrentTransactions = 157286
TransactionInactiveTimeout = 5000
# 3 MySQL Clients
[MYSQLD]
[MYSQLD]
[MYSQLD]

sorry, the above submitted ndb_mgm output shows a not connected ndbd node but i always
verify to get a output like this:

Connected to Management Server at: 10.0.91.118:1186
Cluster Configuration
---------------------
[ndbd(NDB)]     2 node(s)
id=2    @10.0.91.119  (Version: 4.1.9, Nodegroup: 0, Master)
id=3    @10.0.91.120  (Version: 4.1.9, Nodegroup: 0)

[ndb_mgmd(MGM)] 1 node(s)
id=1    @10.0.91.118  (Version: 4.1.9)

[mysqld(API)]   3 node(s)
id=4    @10.0.91.118  (Version: 4.1.9)
id=5    @10.0.91.119  (Version: 4.1.9)
id=6    @10.0.91.120  (Version: 4.1.9)

before starting any test...

Hi,

Could you please provide the queries together with the data the brings this bug forward?

Or is it possible to login to your site an look for the error there?

Very little info to go on, not really a
reproducable test case. Until we have
that we will try and do a code analysis
to see if their is any possible scenario
where a correctly behaving application
can encounter a resource leak.

Note that a misbehaving application
that does not explicitly commit or abort
transactions will leave them allocated
and might use up all connection resources.

I got a testcase from a different bug report.

hi!

sorry for letting you waiting...

i can't give you an account on our cluster servers because they've gone production (yes,
our clients are very hurry)
if you want i can recreate the testing ambient on a couple of spare servers and give you
an account on them...
i noticed that the bug has changed the status from "need feedback" to "patch pending", so
should i assume that you already found the problem about this issue?

best regards

Yes I found and fixed the problem (at least one with similar symptoms)
ChangeSet@1.2148.1.1

It would be nice if you also could retest.
And if it doesn't work, please add a testcase.

/Jonas

sorry for the probably dumb question, but where can i find the patch?

i got the similar bug in mysql cluster5.0.15,i think this is basic action,but can't used.