MongoDB translator and allowDiskUse:true

[asdfasdfhgentry]

Hello,

I'm trying to do a join between two MongoDB tables, but I keep hitting Mongo's 100MiB memory limit on sorting. I need to set allowDiskUse to true, but I can't seem to find how to add this to the Mongo query. Can someone give me a hand with this?

[rareddy]

Can you point me to representative query option in MongoDB?  and an example?

I do not think we added any option like that, but if I see there query, may be can implement such feature to MongoDB translator.

Ramesh..

[asdfasdfhgentry]

The SQL query I'm trying to do is:

SELECT * FROM sales JOIN inventory ON sales.sku=inventory.sku LIMIT 100

Both of these tables are Mongo tables.

In Mongo queries, sorts are limited to 100MiB of memory usage, so my query into these gigantic databases fails. However, setting allowDiskUse:true allows the db to use the disk to store information during the sort. An example of this would be:

db.runCommand(

   { aggregate: "stocks",

   pipeline: [

   { $project : { cusip: 1, date: 1, price: 1, _id: 0 } },

   { $sort : { cusip : 1, date: 1 } }

   ],

   allowDiskUse: true

   }

)

Example from http://docs.mongodb.org/manual/reference/command/aggregate/

What I'm looking for is a way to set this property on every query into the Mongo db.

[rareddy]

I can see if I can add a hint based support to send those options to MongoDB. Can log an enhancement JIRA?

[asdfasdfhgentry]

[TEIID-3166] Allow allowDiskUse setting in MongoDB translator - JBoss Issue Tracker

[rareddy]

Thanks Harrison.

I am interested in knowing how has been your experience in using the MongoDB in Teiid so far? I always looking for ways to improve this further.

Thanks

Ramesh..

[asdfasdfhgentry]

I've been using it for a few weeks now and it has been pretty simple so far. The only trouble I have is when I fail to notice that a Teiid Designer tutorial or documentation is for a different version than the one I'm using. The occasional reference to a button or menu that doesn't exist slows me down a bit. But now that everything is set up, it's very smooth.

[asdfasdfhgentry]

Also, I do have one question; is there a way to see the Mongo query that the translator generates? I can't seem to find it in any logs.

[rareddy]

"org.teiid.CONNECTOR" at debug level at DEBUG level, if not TRACE level. See standlone-teiid.xml file for log configuration or use web-console.

[rareddy]

The fix is available in Teiid 8.9 CR1 for TEIID-3166