问题
ArangoDB Version: 3.3.14
Heap Statistics for application:
{ total_heap_size: 39108608,
total_heap_size_executable: 3670016,
total_physical_size: 37433512,
total_available_size: 8735662896,
used_heap_size: 28891504,
heap_size_limit: 8769069275,
malloced_memory: 16384,
peak_malloced_memory: 168484640,
does_zap_garbage: 0 }
I have a traversal api which traverses through 3 vertices and returns around 300 document vertices. For 200 I get the proper response but when I increase the number of vertices to 300, the traversal api throws an error invalid string length. I have increased the heap space for application to 8GB but as can be seen below the heap_used is way far too less. I am quite not sure if this issue is during serialization to JSON as there is sufficient heap memory available or are there any other options available to get the complete data.
AQL query (if applicable):
{"request":{"vertex":"start_vertex","start_vertex":"service_teams/9a2e582997494bee9066bbcf2aa52218","start_vertices":null,"opts":{"expander":"var connections = [];\n config.datasource.getOutEdges(vertex).forEach(function (e) {\n if( (e._id.indexOf(\"loc_has_parent_loc\") > -1) || (e._id.indexOf(\"loc_is_associated_with_org\") > -1) || (e._id.indexOf(\"st_is_allocated_loc\") > -1) ) {\n connections.push({ vertex: require(\"internal\").db._document(e._to), edge: e});\n }\n });\n return connections;"},"collection_name":"","edge_name":"","data":true,"path":false}},"err":{"code":500,"message":"Invalid string length"}}
回答1:
The error message you're seeing here is a V8 error message, thus this is a javscript implementation limitation. V8 allows strings up to 256 MB.
The old graph traversal API is implemented in Javascript, and for processing may stringify documents inbetween and thus reach this limit.
Please prefer AQL-Traversals instead for better performance.
来源：https://stackoverflow.com/questions/53334437/arangodb-graph-traversal-fails-inspite-of-increased-heap-size