AllegroGraph memoryLimit query option

Question

Where can I set AllegroGraph's memoryLimit query option that is mentioned here?

I am using AllegroGraph 4.9 and keep getting QUERY_MEMORY_LIMIT_REACHED errors when I execute one of my SPARQL queries via WebView.

The log says:

Query has reached memory limit of 4,294,967,296 when requesting 1,089,870,432 additional bytes.
<LISP query plan(?) goes here>
Consider restructuring your query or increasing the value of the :memoryLimit query option.

I will try to improve my query, but I would like to know where that memoryLimitoption lives, too.

Answer 1

AllegroGraph lets you specify several configuration options either in the configuration file or in each specific query. To specify an option in the query, AllegroGraph extends the PREFIX syntax. For example, to alter the memory limit, you would pre-pend:

PREFIX franzOption_memoryLimit: <franz:8g>

It's not common to need to do this so if you can include more details on the query, we can help diagnose and improve things. Another useful option is to log the query:

PREFIX franzOption_logQuery: <franz:yes>

Please contact AllegroGraph support at support@franz.com for more help.