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ID

IEP-76

Author

Pavel Tupitsyn

Sponsor

Pavel Tupitsyn

Created

23 Jun 2021

Status

colour

Grey

title
Green

DRAFT

ACtIVE

Table of Contents

Motivation

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Adapt Ignite 2.x protocol for Ignite 3.0. Main The main differences are:

MsgPack as underlying binary format (IEP-75 Thin Client MsgPack Serialization)
Different A different set of data types (IEP-54: Schema-first Approach)
More flexible and extensible handshake with magic header string

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Every Ignite node listens on a TCP port. Thin client implementations connect to any node in the cluster (possibly multiple nodes) through a TCP socket and perform Ignite operations using a well-defined binary protocol.
Server-side connection parameters are defined in ClientConnectorConfiguration class.
- Default port is 10800.
- Connector is enabled by default, no configuration changes are needed.
Netty is used on the server for network IO.

...

MsgPack is used for data serialization (uses big-endian byte order).

Data Types Mapping

Ignite data types defined in IEP-54 map to MsgPack data types the following way:

Ignite Type	Size	MsgPack Type	Notes
Bitmask(n)	⌈n/8⌉ bytes	bin8 / bin16 / bin32	Extension 8
IntX, UintX	1-8 bytes	fixint / intX / uintX	Integer types are interchangeable when possible. fixint (1 byte) can be passed as a value for uint64 column.
Float	4 bytes	float32
Double	8 bytes	float64
Number([n])	Variable	ext16 (up to 2^8 - 1 bytes)	Extension 1
Decimal	Variable	ext16 (up to 2^8 - 1 bytes)	Extension 2
UUID	16 bytes	fixext16	Extension 3
String	Variable	str
Date	3 bytes	fixext4	Extension 4
Time	4 5 bytes	fixext4ext8	Extension 5
Datetime	7 bytes	fixext8	Extension 6
Timestamp	8 bytes	10 bytes	ext8	Extension 7
IgniteUuid	24 bytes	ext8	Extension 9
NoValue	1 byte	fixext1	Extension 10timestamp 64
Binary	Variable	bin32 (up to 2^32 - 1 bytes)

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MsgPack provides multiple data types for integer values. When encoding a value, the smallest data type for that value is picked automatically.

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Message format

All messages, request requests and responseresponses, except handshake, start with int a 4-byte message length (excluding the length itself).

Any MsgPack int type can be used (see varint above). Empty message will be single 0 byteMessage length is not encoded with MsgPack, 4 bytes contain raw int32 value in little-endian byte order.
Maximum message length is 2147483647 (Integer.MAX_VALUE and maximum byte array length in Java)

int 4 bytes	Length of Payload
...	Payload

Tuple serialization

This IEP covers Table API - Ignite#tables(), which is the only public API available at the moment.
Table API operates on tuples (Tuple and TupleBuilder interfaces).
Tuple is a set of key-value pairs - column name and value.
Values can be of basic types described above and in IEP-54, according to the table schema.
Table schema can evolve over time, columns get added and removed. Ignite tracks the evolution with incrementing integer schema version.
All schema versions are stored by Ignite. It is possible to retrieve the set of columns for any version.

A simple way to serialize a tuple would be to write a map (String → ...) from column name to value.

However, thanks to schema-first approach, we can avoid sending column names with the values (serializing strings is expensive). Instead, we can write an integer schema version, and then values for every column in that schema.

values "type" below indicates a raw sequence of values (not a MsgPack array). Since we know the number of columns in the schema, we don't need an array header.

int	Schema version
values	Column values in schema order. nil when there is no value for a particular column.

To read or write a value for a column, we get the column type from the schema and use corresponding MsgPack data type according to Data Types Mapping above.

Code Block

language	java
title	Tuple serialization (pseudocode)

for (Column col : tuple) {
	switch (col.type().spec()) {
    	case BYTE:
        	packer.packByte(tuple.byteValue(col.name()));
	        break;
	    case SHORT:
...

Key tuples

Key tuples are tuples with key columns only. Key columns always come first in the schema. So if there are 2 key columns, first two values of the tuple is the key.

Null vs NoValue

Ignite Table API handles "column set to null" (1) and "column not set" (2) differently.

Non-nullable column does not allow (1), but allows (2) as long as there is a default value.
Nullable column will be set to null in (1) and to default value in (2).

NoValue custom protocol type reflects this distinction.

Handshake

Request
4 bytes	Magic number 49 47 4E 49, or "IGNI". Helps identifying to identify misconfigured SSL or other apps probing the port.
int	Payload length
int	Version major
int	Version minor
int	Version patch
int	Client code (1 for JDBC, 2 for general-purpose client)
bin	Features (bitmask)
map (string → any)	Extensions (auth, attributes, etc). Server can skip unknown extension data (when client is newer).

...

Response
4 bytes	Magic number 49 47 4E 49, or "IGNI". Helps identifying to identify misconfigured SSL or different server on the port.
int	Payload length
int	Server version major
int	Server version minor
int	Server version patch
int	Error code (0 for success)
string	Error message (when error code is not 0)
int	When error code is 0: Server idle timeout
string	When error code is 0: Server node id
string	When error code is 0: Server node name (consistent id)
bin	When error code is 0: Server features (bitmask)
map (string → any)	When error code is 0: Extensions (auth, attributes, etc). Client can skip unknown extension data (when server is newer).

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Upon successful handshake, client can start performing operations by sending a request with specific op code. Each operation has it's its own request and response format, with a common header.

Request
int	Operation code
int	Request id, generated by client and returned as-is in response
...	Operation-specific data

0 for success error code is not 0

Response
int	Type = 0
int	Request id
int	Flags (1 = partition assignment changed)
long	Observable timestamp (causality token)
uuid or null	Trace id (null for success)
int	Error code (	when trace id is not null)
string	Error message (when	trace id is not null)
string or null	Error stack trace (when trace id is not null)
map or null	Error details (when trace id is not null)
...	Operation-specific data (when trace id is null)

Request or response without operation-specific data is called basic request or basic response below.

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Operation codes and request ids are omitted everywhere below for brevity.

TABLE_CREATE = 1

...

TABLE_DROP = 2

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Basic response.

TABLES_GET = 3

Basic request.

Response
int	N = table count
N * map (UUID + -> string)	pairs map of tables table ids and names

Note: tables can only be created/deleted with SQL, there are no TABLE_CREATE or TABLE_DROP operations.

TABLE_GET = 4

Request
string	table name

...

Response
UUID or nil	table ID or null when a table with the given name does not exist

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Request
UUID	table ID
arr or nil	schema IDs, or null to get alllatest

Response
map (int → array (array))	Map from schema ID to columns. Column is represented by an array of values for: name, type, isKey, isNullable. The array can contain extra data in future for additional properties.

TUPLE_UPSERT = 10

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
arrvalues	values for all columns in given schema (nil when value is missing for a column)

...

Client side is supposed to match provided columns against the latest known schema.

If columns don't match, request the latest schema and try again.
If the latest schema still does not match, and live schema is enabled, use TUPLE_UPSERT_SCHEMALESS

TUPLE_GET =

...

12

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
arrvalues	values for key columns (in schema order)

Response
int or nil	schema id for the current tuple, or nil when there is no matching record
values	values for value columns	arr	tuple values in schema order, when schema id is not nil

Clients should retrieve schemas with SCHEMAS_GET and cache them per table.

TUPLE_UPSERT_ALL =

...

13

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
int	row count
values	arr of arr	array of rows with values for all columns in given schema (nil when value is missing for a column)

Basic response.

TUPLE_GET_ALL =

...

15

Request
UUID	table ID
int or nil	transaction ID
int	schema ID, or nil when result set is empty
int	row count
valuesarr of arr	array of rows with values for key columns (in schema order)

...

Response
int	schema ID (for all tuples in response)
int	row count
values	arr of arr	array of rows with values in schema order

TUPLE_GET_AND_UPSERT =

...

16

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for all columns in given schema (nil when value is missing for a column)

Response
int or nil	schema id for the current tuple, or nil when there is no matching record
values	values for value columns in schema order

TUPLE_INSERT =

...

18

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for all columns in given schema (nil when value is missing for a column)

Response
bool	Insert result

TUPLE_INSERT_ALL =

...

20

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
int	row count
values	rows with values for all columns in given schema (nil when value is missing for a column)

Response
int	schema id, or nil when no rows were skipped
int	skipped row count
values	skipped rows (values in schema order)

TUPLE_REPLACE =

...

22

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for all columns in given schema (nil when value is missing for a column)

Response
bool	Replace result

TUPLE_

...

REPLACE_EXACT = 24

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	oldRec: values for all columns in given schema (nil when value is missing for a column)
values	newRec: values for all columns in given schema (nil when value is missing for a column)

Response
bool	Replace result

TUPLE_GET_AND_REPLACE =

...

26

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for all columns in given schema (nil when value is missing for a column)

Response
int or nil	schema id for the current tuple, or nil when there is no matching record
values	values for value columns in schema order

TUPLE_DELETE =

...

28

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for key columns in given schema

Response
bool	Delete result

TUPLE_DELETE_ALL =

...

29

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
int	row count
values	rows with values for key columns in a given schema

Response
int	schema id, or nil when no rows were skipped
int	skipped row count
values	skipped rows (values for key columns in schema order)

TUPLE_DELETE_EXACT =

...

30

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for all columns in given schema (nil when value is missing for a column)

Response
bool	Delete result

TUPLE_DELETE_ALL_EXACT =

...

31

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
int	row count
values	rows with values for all columns in given schema (nil when value is missing for a column)

Response
int	schema id, or nil when no rows were skipped
int	skipped row count
values	skipped rows (values for key columns in schema order)

TUPLE_GET_AND_DELETE =

...

32

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for all columns in given schema (nil when value is missing for a column)

Response
int or nil	schema id for the current tuple, or nil when there is no matching record
values	values for value columns in schema order, when schema id is not null

TUPLE_CONTAINS_KEY = 33

Request
UUID	table ID
int or nil	transaction ID
int	schema ID
values	values for key columns

Response
bool	whether a tuple with the given key exists

TX_BEGIN = 43

Request
bool	Read-only tx flag
long	Observable timestamp (value from server - see standard response header)

Response
int	Transaction ID

TX_COMMIT = 44

Request
int	Transaction ID

Basic response

TX_ROLLBACK = 45

Request
int	Transaction ID