OK, I got it. I've understood the Q2 by your help, thanks!
Seems like I have to use some other way to draw my images, Here is the updated version Q1: Q1 I found that HFileScannerImpl.getCachedBlock(...) get block from BlockCache. This CachedBlock is used by StoreFileScanner. Is that mean the read model like: *Model A* When a read request come 1. Read 1st Store: a. read BlockCache b. read HFile 2. Read 2nd Store: a. read BlockCache b. read HFile 3. ...... 4. Read Memstore Or there is only one BlockCache and all the read request will go through it first, like: *Model B:* When a read request come 1. Read BlockCache 2. Read 1st Store -> read HFIle 3. Read 2nd Store -> read HFile 4. .... 5. Read Memstore Thanks, Alex 2018-05-01 20:04 GMT-07:00 Josh Elser <els...@apache.org>: > FYI, the mailing list strips images. > > There is only one BlockCache per RS. Not sure if that answers your Q1 in > entirety though. > > Q2. The "Block" in "BlockCache" are the blocks that make up the HBase > HFiles in HDFS. Data in the Memstore does not yet exist in HFiles on HDFS. > Additionally, Memstore is already in memory; no need to have a different > cache to accomplish the same thing :) > > On 5/1/18 9:25 PM, Xi Yang wrote: > >> Sorry to bother you guys. May I ask 2 questions about HBase? >> >> Q1 >> >> I found that |HFileScannerImpl.getCachedBlock(...)| get block from >> BlockCache. This CachedBlock is used by |StoreFileScanner|. Is that mean >> the read model like: >> >> *Model A* >> >> Or there is only one BlockCache and all the read request will go through >> it first, like: >> >> *Model B:* >> >> >> Q2 >> If the data been read from Memstore, will it be put in BlockCache to >> accelerate the read process next time? >> >> >> Thanks, >> Alex >> >> >> >
