Data transfering: faster, stronger, better and not harder. UA Mobile 2016.

Data transferringfaster, stronger, better and not harder

DisclaimerData transferring optimizations requires both, client side and server side development, could be hard to implement and it could break your system (and may be life)

...But it worth to be done

Is it really a problem?

General advice● GZIP● Cache (!!!)● Partial requests/responses● Minimize data structure● Use streams where possible● Use Binary formats

GZIP● Network cost vs CPU● Measure it

Cache● Client DB● Network client level cache● Server side support (ETag, Cache-Control, etc.)● Use push notifications for cache invalidating

Partial requests/responses

Partial requests/responses● Transfer only what you really need● Control field count (Data Diet)● Pagination is our friend


https://www.googleapis.com/demo/v1?key=YOUR-API-KEY


https://www.googleapis.com/demo/v1?key=YOUR-API-KEY

{ "kind": "demo",

...

"items": [

{

"title": "First title",

"comment": "First comment.",

"characteristics": {

"length": "short",

"accuracy": "high",

"followers": ["Jo", "Will"],

}, ... ]

}


https://www.googleapis.com/demo/v1?key=YOUR-API-KEY&fields=kind,items(title,characteristics/length)


https://www.googleapis.com/demo/v1?key=YOUR-API-KEY&fields=kind,items(title,characteristics/length)

{ "kind": "demo",

"items": [

{



"length": "short"

}

}, ... ]

}


{ "kind": "demo",

...

"items": [

{


"comment": "First comment.",


"length": "short",

"accuracy": "high",

"followers": ["Jo", "Will"],

}, ... ]

}

{ "kind": "demo",

"items": [

{



"length": "short"

}

}, ... ]

}


{ "kind": "demo",

...

"items": [

{

"title": "First title", "comment": "First comment.", "characteristics": { "length": "short", "accuracy": "high", "followers": ["Jo", "Will"], }, ... ]

}

{ "kind": "demo",

"items": [

{

"title": "First title", "characteristics": { "length": "short" }

}, ... ]

}

Fields parameter syntax summary● Use a comma-separated list to select multiple fields.● Use a/b to select a field b that is nested within field a; use a/b/c to select a

field c nested within b. ● Exception: For API responses that use "data" wrappers, where the response

is nested within a data object that looks like data: { ... }, do not include "data" in the fields specification. Including the data object with a fields specification like data/a/b causes an error. Instead, just use a fields specification like a/b.

Fields parameter syntax summary● Use a sub-selector to request a set of specific sub-fields of arrays or objects

by placing expressions in parentheses "( )".

For example: fields=items(id,author/email) returns only the item ID and author's email for each element in the items array. You can also specify a single sub-field, where fields=items(id) is equivalent to fields=items/id.

Fields parameter syntax summary● Use wildcards in field selections, if needed.

For example: fields=items/pagemap/* selects all objects in a pagemap.

Use PATCH (yes, there is a HTTP Verb “PATCH”)● https://tools.ietf.org/html/rfc5789● If you’ve changed one field - send one field● Retrofit support included ;)● Could be used with Partial Responses

General advice● GZIP● Cache (!!!)● Minimize data● Minimize data structure● Use streams where possible● Use Binary formats

Minimize data structure

● Remove spaces● Remove long field’ names● Remove braces● Remove data (see previous slides)

Make you data homogeneousWhat is an Homogenous Collection?

Before...

[

{"a":"A","b":"B"},

{"a":"C","b":"D"},

{"a":"E","b":"F"}

]

After…

[2,"a","b","A","B","C","D","E","F"]

Tools● CJSON Algorithm● JSON.hpack Algorithm● Brain (use it carefully)

Why streams?● Start parsing from the first byte● Reduce memory usage● Most of the tools support it by default

Binary formats● Fast● Small● Optimized for every platform● Static typed

Binary formats● Protobuf● Thrift (Never used it :( )● Cap’n proto

Protobufmessage Person {

required string name = 1;

required int32 id = 2;

optional string email = 3;

}

ProtobufPerson john = Person.newBuilder()

.setId(1234)

.setName("John Doe")

.setEmail("[email protected]")

.build();

output = new FileOutputStream(args[0]);

john.writeTo(output);

Protobuf● Advanced android support (Retrofit, Wire, etc.)● Obj-c/Swift/JS are also supported● Easy to implement on server side

Cap’n proto● Faster than Protobuf● Same author● No Obj-C/Swift support (use C++ and suffer)● No Android specific realization (Java only)● BETA

Why it worth to check● Incremental reads● Random access● Mmap support● Tiny generated code● Tiny runtime library

Why you shouldn’t use it in production● Still BETA● Has not yet had a security review● The Cap’n Proto programming interface may still change in ways that break

existing code● Performance (“Currently it only beats Protobufs in realistic-ish end-to-end

benchmarks by around 2x-5x. We can do better”)

Cap’n proto: Schemastruct Person { name @0 :Text = “Bob”; birthdate @3 :Date;

email @1 :Text = “[email protected]”; phones @2 :List(PhoneNumber);

struct PhoneNumber { number @0 :Text; type @1 :Type;

enum Type { mobile @0; home @1; work @2; } }}

Cap’n proto: Schema● Types come after names● @N annotations● # Comments also are supported (should appear after the declaration)

Cap’n proto: Built-in Types● Void: Void● Boolean: Bool● Integers: Int8, Int16, Int32, Int64● Unsigned integers: UInt8, UInt16, UInt32, UInt64

● Floating-point: Float32, Float64

● Blobs: Text, Data

● Lists: List(T)

Cap’n proto: Unionsstruct Shape { area @0 :Float64;

union { circle @1 :Float64; # radius square @2 :Float64; # width }}

Cap’n proto: Unions● Unions members are numbered in the same number space as fields● “Void” is useful if no value is needed● By default, when a struct is initialized, the lowest-numbered field in the union

is “set”

Cap’n proto: Groupsstruct Person { # ...

# Note: This is a terrible way to use groups, and meant # only to demonstrate the syntax. address :group { houseNumber @8 :UInt32; street @9 :Text; city @10 :Text; country @11 :Text; }}

Cap’n proto: Groups● Behaves as one field of other structure (address :Address)● Group is not separated object!● Essentially, a group is just a namespace● Useful with Unions

Cap’n proto: Groupsstruct Shape { area @0 :Float64;

union { circle :group { radius @1 :Float64; } rectangle :group { width @2 :Float64; height @3 :Float64; } }}

Cap’n proto: Other features● Dynamically-typed Fields● Enums● Interfaces (RPC)● Generic Types● Generic Methods (RPC)● Constants● Nesting, Scope, and Aliases● Imports● Annotations

Cap’n proto: Other features

Summary● Don’t transfer data at all● If you should transfer something - get only part that you need● ...then minimize data structure of that part● ...then compress it● ...then optimize data parsing● ...then cache result it and see p.1● Use binary data!

Thanks!URLs:

https://capnproto.org/https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/http-caching?hl=enhttps://developers.google.com/site-verification/v1/performancehttps://developers.google.com/protocol-buffers/

Contact me:

Twitter: @AntonMinashkinEmail: [email protected]: https://www.facebook.com/anton.minashkin.1

Data transfering: faster, stronger, better and not harder. UA Mobile 2016.

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Transcript of Data transfering: faster, stronger, better and not harder. UA Mobile 2016.