Hello!
I've read the HBase architecture from the book
http://hbase.apache.org/book.html#architecture (HBA)
and confronted with HBase definitive guide (HBDG)
http://ofps.oreilly.com/titles/9781449396107/architecture.html
Some questions raised:
1. How many MemStores can have Region?
HBDG: "A HRegion also has a MemStore"
HBA: "A Store hosts a MemStore". A Store corresponds to a column family for a
table for a given region.
2. How many HLog instances are created per Region Servers?
HBDG:"A HRegion also has [...] a HLog instance"
HBA: "[...]and there is one HLog instance per RegionServer. "
3. After reading the HBA, I've concluded (please correct me if I'm wrong), that
the are these reletionships
a) A RegionServer has one HLog instance
b) A RegionServer has one .META. table that holds meta information about
many HTable
c) A HTable can be split in many Regions.
d) A HTable can have many column family
e) A Column family has one Store
f) A Store can have zero ore more HFile instances
g) A Store can one MemStore
h) A column family can have zero or many columns
I'll look forward for your opinions and answers...and please complete with your
knowledge.
Thank you.
Regards,
Florin
