Nebula Graph v2.5.1

bug fix:

• Fixed the performance reduction problems caused by the sessions will update at the next upload period when use space. #1355

• Fixed the performance problems of k8s caused by processing logic of the remote address in connection requests. vesoft-inc/nebula-common#615

download:

• CN: https://nebula-graph.com.cn/download/
• EN: https://nebula-graph.io/download/

Nebula Graph v2.5.0

feature

• Support management of session. #280
• Support terminate the slow queries, know issue: there is a delay in querying and terminating the query due to the implementation. #1152
• Enhance the ability to extract the indices from expressions for Lookup statement. #1188
• Supports configuring machine memory watermarks to alleviate OOM issues to some extent. #1067
• Support filter the edges in FindPath statement. #1091
• Support return structure of a graph without properties in Subgraph statement. #1134
• Improve the usage of timestamp function. vesoft-inc/nebula-common#515
• Support for querying the version of each service. #944
• Index and TTL can be supported together. #382
• Support the creation of full-text indexes on specified properties. #460
• Support make comment when create space or schema. #895
• Support for full-text index rebuild. #1123

bug fix

• Fixed multiple statement execution problems caused by permissions. #1165
• Fixed unwinding causing no results. #1018
• Fixed crash problems caused by aggregation functions in some scenarios. #1015
• Fixed index matching problems with OR expressions. #1005
• Fixed case sensitivity of functions. #927
• Fixed issue where query index creation information was not checked for Tag/Edge type. #933
• Fixed a bug in the Substring function. vesoft-inc/nebula-common#491
• Fixed meta not returning leader change correctly. #423
• Fixed an issue with 'LIMIT', 'ORDER', 'GROUP' statements using variables. #1314
• Fixed issue with db_dump tool printing VID of int type. vesoft-inc/nebula-storage#533
• Fixed the issue that FAILE is still displayed after the Balance task is recovered. vesoft-inc/nebula-storage#528

enhancement

• The Listener interface is optimized to support full data acquisition. #465，#484
• The leader table of the meta is reorganized. #439
• Add a DiskManager to check disk capacity. #461
• Improve heartbeat of raft to avoid leader change. #438
• Support concurrently go/fetch/lookup in storage. #503
• Enhanced for the EXISTS function to the MAP. #973
• Enforce the use of aggregate functions, such as COUNT(v)+AVG(v). #968

change

• A little bit grammar change of Subgraph

# Add the WITH PROP keyword to the output property
GET SUBGRAPH WITH PROP FROM <vids>

# The original syntax will only output the graph structure without properties
GET SUBGRAPH FROM <vids>

• we must use the symbol $-. in ‘ORDER BY’. But in earlier versions, there is no need. Example:

Before:
(root@nebula) [basketballplayer]> LOOKUP ON player \
                               ->         YIELD player.age As playerage \
                               ->         | GROUP BY $-.playerage \
                               ->         YIELD $-.playerage as age, count(*) AS number \
                               ->         | ORDER BY number DESC, age DESC;


From v2.5.0
(czp@nebula) [basketballplayer]> LOOKUP ON player \
                               ->         YIELD player.age As playerage \
                               ->         | GROUP BY $-.playerage \
                               ->         YIELD $-.playerage as age, count(*) AS number \
                               ->         | ORDER BY $-.number DESC, $-.age DESC;

Nebula Graph v2.0.1

Improvements

• Optimize the performance of StorageClient vesoft-inc/nebula-common#468
• HTTP GetFlags interface adds support for Unsigned Integers vesoft-inc/nebula-common#469
• Add check for Raft Listener and Storage Service IP/Port conflicts #875, vesoft-inc/nebula-common#470

Bugfix

• Fix the issue that the GO statement fails to yield the source vertex properties #859
• Fix the issue that the services may fail to start when the logs directory does not exist #873 vesoft-inc/nebula-storage#403
• Fix the issue that FIND SHORTEST PATH xxx UPTO N STEPS return N+1 steps' path when N is an odd number.#912
• Fix the issue when taking the output of a query as the input of the DELETE statement, SementicError is returned #917
• Fix the issue that the return value of the aggregation function is inconsistence with openCypher if no item is found #901 vesoft-inc/nebula-common#480
• Fix the issue that GetNeighborsIter() may return partial results in cluster mode. #922
• Fix the issue that illegal filtering of aggregate functions in the MATCH ... WHERE clause makes graphd crash. #919
• Fix SemanticError problem when seeking by negative vid #932
• Fix the issue that the TAG/EDGE specification does not work in SHOW CREATE TAG/EDGE INDEX clauses #933 vesoft-inc/nebula-storage#426
• Fix the issue that REBUILD INDEX returns succeed even if failed sometimes. vesoft-inc/nebula-storage#405
• Fix the issue that the indexes of newly inserted data may fail to update during the rebuilding index process. vesoft-inc/nebula-storage#408
• Fix the issue that using NULL in substr() or substring() makes graphd crash vesoft-inc/nebula-common#491

Nebula Graph v2.0 GA

New Features

• vertexID supports both Integer and String.
• New data types:
  • NULL: the property can be set to NULL. NOT NULL constraint is also supported
  • Composite types: LIST, SET, and MAP(Cannot be set as property types)
  • Temporal types: DATE and DATETIME.
  • FIXED_STRING: a fixed size String
• Full-text indexes are supported to do prefix, wildcard, regex, and fuzzy search on a string property.
• Explain & Profile outputs the execution plan of an nGQL statement and execution profile.
• Subgraph to retrieve vertices and edges reachable from the start vertices.
• Support to collect statistics of the graph space.
• OpenCypher compatibility
  • Partially support the MATCH clause
  • Support RETURN, WITH, UNWIND, LIMIT & SKIP clauses
• More built-in functions
  • Predicate functions
  • Scalar functions
  • List functions
  • Aggregating functions
  • Mathematical functions
  • String functions
  • Temporal functions

Improvements

• Optimize the performance of inserting, updating, and deleting data with indexes.
• LOOKUP ON filtering data supports OR and AND operators.
• FIND PATH supports finding paths with or without regard to direction, and also supports excluding cycles in paths.
• SHOW HOSTS graph/meta/storage supports to retrieve the basic information of graphd/metad/storaged hosts.

Changelog

• The data type of vertexID must be specified when creating a graph space.
• FETCH PROP ON returns a composite object if not specify the result set.
• Changed the default port numbers of metad, graphd, and storaged.
• Refactor metrics counters.

Nebula-graph Console

Supports local commands mode. :set csv outputs the query results to the console and the specified CSV file. For more information, please refer to https://github.com/vesoft-inc/nebula-console.

Clients

Support connection pool and load balance.

• cpp client https://github.com/vesoft-inc/nebula-cpp
• java client https://github.com/vesoft-inc/nebula-java
• python client https://github.com/vesoft-inc/nebula-python
• go client https://github.com/vesoft-inc/nebula-go

Nebula Graph Studio

With Studio, you can create a graph schema, load data, execute nGQL statements, and explore graphs in one stop. For more information, please refer to https://github.com/vesoft-inc/nebula-web-docker.

Known Issues

• #860

Nebula Graph Release v2.0.0-RC1

New Features

• Add Integer vertexID support #496 vesoft-inc/nebula-common#351, vesoft-inc/nebula-storage#246, vesoft-inc/nebula-docs#264
• FIND PATH supports to find paths with or without regard to direction #464, and also supports to exclude cycles in paths #461.
• SHOW HOSTS graph/meta/storage supports to retrieve the basic information of graphd/metad/storaged hosts. #437 vesoft-inc/nebula-common#325 vesoft-inc/nebula-storage#223
• BALANCE DATA RESET PLAN supports resetting the last failed plan vesoft-inc/nebula-common#342 vesoft-inc/nebula-storage#232.
• Enhance MATCH clause support, for more information please visit Match doc.
• Add path manipulation support vesoft-inc/nebula-common#306, vesoft-inc/nebula-common#358

Changelog

• Changed the default port numbers of metad, graphd, storaged. #474, vesoft-inc/nebula-storage#239

Nebula Graph v2.0.0-beta

Nebula Graph

Note: Schema & data are not compatible with 1.0 yet. Still working on the compatibility.

Compatibility with more nGQL 1.x queries

• DESCRIBE TAG/EDGE INDEX is to obtain information about the index.
• REBUILD TAG/EDGE INDEX is to rebuild an index.
• SHOW TAG/EDGE INDEXES is to list the created indexes.
• SHOW TAG/EDGE INDEXES STATUS is to return the created index status.

New Features

• full-text search, allows users to write queries that match terms anywhere within the indexed string properties.
• LOOKUP ON TAG/EDGE is to get all vertices of a tag or edges of an edge type.
• SUBMIT JOB STATS & SHOW STATS is to get all vertices and edges in the current space.
• Support more openCypher Clauses.
  • Partially supported MATCH clause
  • RETURN & DISTINCT
  • LIMIT & SKIP
• Add more built-in functions
  • Predicate functions
  • Scalar functions
  • List functions
  • Aggregating functions
  • Mathematical functions
  • String functions
  • Temporal functions

Clients

• CPP Client.

Nebula Graph Studio

• Compatible with Nebula Graph 2.x，refer to Studio.

Tools

• Go Importer: Compatible with Nebula Graph 2.x, refer to Nebula Importer.

Nebula Graph v2.0.0-alpha

Nebula Graph

Note: Schema & data are not compatible with 1.0 yet. Still working on the compatibility.

New Features

• Support String vertex ID
• New data types
  • NULL, the property for vertices or edges can be set to NULL. NOT NULL constraint is supported to ensure the property values are not NULL.
  • Composite types: list, set and map(Cannot be stored as properties).
  • Temporal types like DATE and DATETIME.
• New Functions
  • size() returns the number of items in a list
  • time() returns the current Time
  • date() or datetime() Returns the current Date or DateTime
  • id() returns the id of a vertex
  • tags() and labels() return the tags of the vertex
  • collect(), an aggregation function, returns a list containing the values returned by an expression
  • collect_set(), aggregation function, returns a set containing the values returned by an expression
  • properties() returns a map containing all the properties of a vertex or an edge
  • type() returns the edge type of an edge
  • src() returns the src id of an edge
  • dst() returns the dst id of an edge
  • rank() returns the rank of an edge
• New Operators
  • IN checks if a specified value matches any value in a list.
  • CONTAINS performs a case-sensitive match regardless of location within a string.
  • STARTS WITH performs a case-sensitive match for the beginning of a string.
  • ENDS WITH performs a case-sensitive match for the ending of a string.
• Explain & Profile. EXPLAIN displays the execution plan of a nGQL statement without executing the statement. PROFILE executes the statement, then outputs the execution plan as well as the execution profile.
• Subgraph. GET SUBGRAPH statement retrieves information of vertices and edges reachable from the start vertices over the specified edges to the maximum number of hops.
• Partially supported MATCH statement.
• A DELETE statement can have an input from the pipeline |.

Features different from 1.0

• CREATE SPACE supports specifying the type of vertex ID. The type fixed_string( int64 will be supported in the next release).
• Simplify UPDATE/UPSERT statement.
• UPSERT ... SET the unspecified properties will be set to the default value when inserting a new vertex/edge. If no default value is set, they will be set to NULL. If the NOT NULL constraint is set on the property, an error will return.
• $- in the pipeline statement is not equal to $-.id anymore.
• The expression specified in the default value will be computed when the data inserted instead of schema defined.

Upcoming Soon (Work in process)

• DESCRIBE TAG/EDGE INDEX
• REBUILD TAG/EDGE INDEX
• SHOW TAG/EDGE INDEXES
• SHOW TAG/EDGE INDEX STATUS
• FETCH PROP ON multiple tags
• Compatible with 1.0 Integer vertex ID
• Support more OpenCypher statements
• Backup & Restore
• Fulltext search

Console

• Nebula-console supports local commands now. For example, :set csv outputs the query results to the console and the specified CSV file. For more information, please refer to nebula-console.

Clients

• Java
• Python
• Golang

Clients support connection pooling and load balancing. For more information, please refer to nebula-clients.

Studio

• Not Compatible with Nebula Graph 2.0 yet (Working in progress).

Document

• Please refer to https://github.com/vesoft-inc/nebula-docs/tree/master/docs_2.0.