String De-Duplication Support

[thalapura-alapurom]

Hi

During ExecutableGraphQL generation, it would be better to deduplicate string, since it occupied a considerable amount of memory due to duplication of string objects.

You could see that String alone took 4 MB.

Within that due to duplication, the size of single string is around 674KB. Took only took 2 object for reference.

So we would recommend to optimise this object with string deduplication concept. Also it will be great if the GraphQL object is serialisable (For compression purpose).

[bbakerman]

Do you have any more insight on how we are duplicating strings. I don't undertand what you are showing in that second screen shot.

In general I would assume we mostly just point to string objects created initially from the SDL parse.

eg

        builder.name(typeDefinition.getName());

==

    public B name(String name) {
        this.name = name;
        return (B) this;
    }

The above is mostly what we do - that is set a pointer to the original string.

So I would love to get insight in where we might be doing String sCopy = new String(sOriginal.getChars()) say

Also it will be great if the GraphQL object is serialisable (For compression purpose).

A GraphQL object contains data and code. So how would the custom code like a registry of DataFetchers be serialized? Also how does serialisaton related to compression in a memory runtime sense ?

[thalapura-alapurom]

Lets say I have 2 types which have some common fields say field1. When parsing sdl, 2 field1 string objects will be created. Hence duplication occurs.

Hence instead of directly assigning values, if we use string interning, then only one instance will be created for each strings.

public B name(String name) { this.name = name; return (B) this; }
will be replaced as
public B name(String name) { this.name = name.intern(); return (B) this; }

[thalapura-alapurom]

Regarding serialisation, if an object is serialisable, I can convert the object into a sequence of characters and store it in a file system. Later we can retrieve the same and deserialise into original object

[stefanstrat27]

Regarding serialisation, if an object is serialisable, I can convert the object into a sequence of characters and store it in a file system. Later we can retrieve the same and deserialise into original object

I'm not 100% sure, but you might be able to store it as a binary file (the Java object itself) rather than a text file (serialized into JSON or something)

[bbakerman]

for the record this PR from our friends at Netflix (originally) will help in this regard

#3504

[bbakerman]

Closing this issue as addressed (somewhat) in the linked PR via v22