CockroachDB

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Jingguo Yao edited this page Jun 26, 2016 · 95 revisions

Issue

TODO

opentracing, Dapper
The the wiki page: Life of a transaction
HLC implementation code

Go:

go gRpc API
go net API

Cockroach:

trace a single a single get and insert KV SQL. - How to lookup a row from the KV cluster - Who is the transaction coordinator? - Who is the split coordinator?

Memo

Review Raft paper and watch Raft video. Raft replicates ops one by one. Or tow ops can proceed in parallel?
The following two paragraphs from design doc seems to conflict with each other:

Paragraph 1:

If a new range replica leader is elected, it sets the low water mark for the cache to the current wall time + ε (ε = 99th percentile clock skew).

Paragraph 2:

This is accomplished by setting the low water mark of the timestamp cache to the expiration of the previous lease plus the maximum clock offset.

What is the difference between clock skew and clock offset?
Internals of MongoDB, VoltDB, CouchBase and Lucene index as illustrated in the diagram of Read vs. Write Optimization Spectrum section.
util/http.go mentions ProtoEncoding includes application/x-protobuf and application/x-google-protobuf.. But protorpc now uses application/octet-stream and application/x-google-protobuf.
References: http://stackoverflow.com/a/1425984/431698

Spanner VS CockroachDB

Spanner has fragments, directory, tablet and spanserver. CockroachDB has range and nodes.
Spanner uses one Paxos group for one tablet. CockroachDB use one Raft group for one node (MultiRaft).
Spanner many have multiple hierarchies. CockroachDB use one monolithic map for all tables.