Re: Reconnecting automatically after DB downtime

On 29/02/2016 9:53pm, Hugi Thordarson wrote: > Hi all. > We had some DB problems last night (MariaDB with the ConnectorJ driver). As > soon as I had started the DB back up, our EOF applications were up and > running, but the Cayenne apps were still down and required a restart to start > running

Reconnecting automatically after DB downtime

Hi all. We had some DB problems last night (MariaDB with the ConnectorJ driver). As soon as I had started the DB back up, our EOF applications were up and running, but the Cayenne apps were still down and required a restart to start running again. Is there any way to tell Cayenne to reconnect

Re: Reconnecting automatically after DB downtime

Hi Michael, I’m not quite sure, I’m just giving Cayenne my connection information. Should I be using a different mechanism? Cheers, - hugi > On 29. feb. 2016, at 13:10, Michael Gentry wrote: > > Hi Hugi, > > Just out of curiosity, which connection pooling mechanism

Re: Reconnecting automatically after DB downtime

Thanks Andrus. I do have “autoReconnect=true” in the string but added the connectionTimeout, perhaps that helps. What does validationQuery do? Cheers, - hugi // Hugi Thordarson // http://www.loftfar.is/ // s. 895-6688 > On 29. feb. 2016, at 10:57, Andrus Adamchik

Re: Reconnecting automatically after DB downtime

Ah, awesome. Added to my config :). Cheers, - hugi > On 29. feb. 2016, at 11:25, Andrus Adamchik wrote: > > >> On Feb 29, 2016, at 2:20 PM, Hugi Thordarson wrote: >> >> What does validationQuery do? > > Periodically executes for each pooled

Re: Reconnecting automatically after DB downtime

> On Feb 29, 2016, at 2:20 PM, Hugi Thordarson wrote: > > What does validationQuery do? Periodically executes for each pooled connection, and kills connections that throw during validation. So it ensures that all pooled connections are in a good state. Andrus

Counting the number of destination objects for a to-many relationship (or checking if empty)

Hi all, Is there any simple way or me to count the number of destination objects of a to-many relationship? (without fetching) If not, is there some way to generate an expression from a relationship, so I can use that expression in my own counting functions? Cheers, - hugi

Re: Reconnecting automatically after DB downtime

Probably a DataSource configuration. I am using DB urls like this: jdbc:mysql://127.0.0.1/db?connectTimeout=0=true=true=UTF-8 and also add "validationQuery" parameter to my pool config. Both ensure reconnects are transparent. Andrus > On Feb 29, 2016, at 1:53 PM, Hugi Thordarson

Re: Reconnecting automatically after DB downtime

I’m using Cayenne’s internal mechanism for everything related to the DB and currently using 4.0.M4-SNAPSHOT. The stack trace we were getting (after restarting the DB, and the EOF programs had started working) was: Caused by:

Re: Reconnecting automatically after DB downtime

Hi Hugi, I don't know the nature of your application. I've used Cayenne's native connection pooling (stand-alone applications) and JNDI (typically based on Apache Commons DBCP) in the past. If my memory is correct, Cayenne's native connection pooling does attempt to do a re-connect on failure.

Re: Counting the number of destination objects for a to-many relationship (or checking if empty)

PS. I think the code works correctly, but let me know if it doesn't. On Mon, Feb 29, 2016 at 1:09 PM, Michael Gentry wrote: > Hi Hugi, > > I'm not sure if this will work for 4.0 (since earlier you said you are > using it), but this is what I'd use for 3.1: > > >

Re: Counting the number of destination objects for a to-many relationship (or checking if empty)

Hi Hugi, I'm not sure if this will work for 4.0 (since earlier you said you are using it), but this is what I'd use for 3.1: https://github.com/mrg/cbe/blob/master/FetchingObjects/Aggregates/src/main/java/cbe/fetching/utilities/AggregateUtils.java If you have A->>B, you'd construct a