Dgraph 1.0.12 发布，事务性的分布式图形数据库-Linuxeden开源社区

Dgraph 1.0.12 已发布，Dgraph 是一个可扩展的，分布式的，低延迟的图数据库，目标是提供 Google 生产水平的规模和吞吐量，在超过 TB 的结构数据里，为用户提供足够低延迟的实时查询。Dgraph 支持 GraphQL 作为查询语言，响应 JSON。

新版更新内容如下：

gRPC 和 HTTP 请求支持 gzip 压缩。 (#2843)
可以从完整二进制的备份还原。这时是一个遵循 Dgraph Community License 的企业级特性。
通过 --mutations flag 实现的严格架构模式。默认的 --mutations=allow 允许所有 mutations； --mutations=disallow 禁用所有 mutations； --mutations=strict 只允许在架构中定义的谓词（predicates）的 mutations。修复 #2277。
新增用于调试和测试的工具 dgraph increment 。该增量工具可以查询指定谓词（默认： counter.val），增加它的整数计数器值，之后转化结果成图形。可用于测试端到端的 txns 以确认簇（cluster）的状况。 (#2955)
支持 best-effort 查询。这将放宽 linearizible reads 的要求。使用 best-effort 查询，Alpha 将请求内存的时间戳，而不是给 Zero 发出一个出战请求。(#3071)

Use the new Stream API from Badger instead of Dgraph’s Stream framework. (#2852)
Discard earlier versions of posting lists. (#2859)
Make HTTP JSON response encoding more efficient by operating on a bytes buffer directly. (ae1d9f3)
Optimize and refactor facet filtering. (#2829)
Show badger.Item meta information in dgraph debug output.
Add new option to dgraph debug tool to get a histogram of key and value sizes. (#2844)
Add new option to dgraph debug tool to get info from a particular read timestamp.
Refactor rebuild index logic. (#2851, #2866)
For gRPC clients, schema queries are returned in the Json field. The Schema proto field is deprecated.
Simplify design and make tablet moves robust. (#2800)
Switch all node IDs to hex in logs (e.g., ID 0xa instead of ID 10), so they are consistent with Raft logs.
Refactor reindexing code to only reindex specific tokenizers. (#2948)
Introduce group checksums. (#2964, #3085)
Return aborted error if commit ts is 0.
Reduce number of “ClusterInfoOnly” requests to Zero by making VerifyUid wait for membership information. (#2974)

Remove LRU cache from Alpha for big wins in query latency reduction (5-10x) and mutation throughput (live loading 1.7x faster). Setting --lru_mb is still required but will not have any effect since the cache is removed. The flag will be used later version when LRU cache is introduced within Badger and configurable from Dgraph.
Remove --nomutations flag. Its functionality has moved into strict schema mode with the --mutationsflag (see Added section).

Use json.Marshal for strings and blobs. Fixes #2662.
Let eq use string “uid” as value. Fixes #2827.
Skip empty posting lists in has function.
Fix Rollup to pick max update commit ts.
Fix a race condition when processing concurrent queries. Fixes #2849.
Show an error when running multiple mutation blocks. Fixes #2815.
Bring in optimizations and bug fixes over from Badger.
Bulk Loader for multi-group (sharded data) clusters writes out per-group schema with only the predicates owned by the group instead of all predicates in the cluster. This fixes an issue where queries made to one group may not return data served by other groups. (#3065)
更新详情（需要注意：由于底层数据格式的改动，新版要求使用者先导出数据，升级或回滚后再将数据导入。）

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转自 https://www.oschina.net/news/104959/dgraph-1-0-12-released