>> Are >> we suffering performance hits when we do queries on 60+ columns? > > No. Extra information referenced in the view is pruned away if it isn't > directly in your query so you don't pay any penalty for excess complexity > described in the view.
Unless it's a bug of course, like DRILL-2412 <https://issues.apache.org/jira/browse/DRILL-3412>. If you see any performance hits, check the query's plan, if the scan is reading more columns than needed it may be a bug. On Thu, Aug 6, 2015 at 5:22 PM, Ted Dunning <[email protected]> wrote: > On Sat, Aug 1, 2015 at 5:53 PM, John Omernik <[email protected]> wrote: > > > I am working with this as well and I find the "abstraction" frustrating > > from a user perspective as well. > > > Yes. It can be a pain. > > > > I understand we can create views, I've > > done that, but it's a tedious process of ensuring my syntax is correct > and > > one that I did have the Schema on hand to easily do this. Could a > feature > > be added to "register" a view doing this for us based on the schema" ? > > > It should be relatively easy to build a tool to convert schema information > that you have into a view definition. > > > > > Are > > we suffering performance hits when we do queries on 60+ columns? > > > No. Extra information referenced in the view is pruned away if it isn't > directly in your query so you don't pay any penalty for excess complexity > described in the view. > > > > This > > would make this integration much more intuitive for users who know sql, > > know their data is in an hbase table, and just want to go query. (Trying > to > > make this more self serve for users) > > > > Yes. A GUI would be a nice-to-have here. It isn't clear if this will be > high enough priority to happen right away. > > > > > > > > John > > > > On Sat, Aug 1, 2015 at 2:53 AM, Usman Ali <[email protected]> > > wrote: > > > > > I understand creating views and querying on them. But my problem is, I > > don > > > not have schema of the table, therefore I can not create views on the > > > table. The only thing I know about the table is that each column > > contains a > > > "utf-8" encoded string. Now what I want to do to is to query the table > > (not > > > the view) through Restful APIs and get column values in bytes in my > > > response json. Then I want to convert those byte values to my original > > > string. For eample my rresponse json is : > > > { > > > myFamily: "{ "name" : "name string in bytes" , "address" : > > "address > > > string in bytes"}' > > > > > > } > > > > > > Now , I want to convert byte values of name and address to original > > string. > > > I hope I am clear in stating my problem. > > > Any other work around this problem is also welcome. > > > > > > Thanks, > > > Usman Ali > > > > > > > > > On Sat, Aug 1, 2015 at 8:12 AM, Jacques Nadeau <[email protected]> > > wrote: > > > > > > > Got it. Was just concerned that the person might be confused by your > > > > example using CAST when we were talking about CONVERT. I think we > need > > > to > > > > come up with a simpler/clearer way to express the differences since > > > people > > > > keep tripping up on this. > > > > > > > > -- > > > > Jacques Nadeau > > > > CTO and Co-Founder, Dremio > > > > > > > > On Fri, Jul 31, 2015 at 7:59 PM, Carol McDonald < > > [email protected]> > > > > wrote: > > > > > > > > > the point I was trying to make is : > > > > > The good news is, Drill does provide a nice simple way to abstract > > > these > > > > > details away. You simply create a view on top of HBase [1]. The > > view > > > > can > > > > > contain the physical conversions. Then users can interact with the > > > view > > > > > rather than the underlying table. > > > > > > > > > > On Fri, Jul 31, 2015 at 11:36 AM, Jacques Nadeau < > [email protected] > > > > > > > > wrote: > > > > > > > > > > > Carol, your statements are misleading. There are some situations > > > where > > > > > > people have stored in HBase encoded as text. In other cases, > > they've > > > > > used > > > > > > a straight binary encoding. CAST is used generally used when the > > > data > > > > is > > > > > > already encoded as a UTF8 string. Otherwise, the user should use > > > > > > CONVERT_FROM to decode the binary value. > > > > > > > > > > > > -- > > > > > > Jacques Nadeau > > > > > > CTO and Co-Founder, Dremio > > > > > > > > > > > > On Fri, Jul 31, 2015 at 7:42 AM, Carol McDonald < > > > > [email protected]> > > > > > > wrote: > > > > > > > > > > > > > This blog shows an example using REST , drill , and HBase. In > > this > > > > > > example > > > > > > > a view converts the HBase byte values to strings > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > https://www.mapr.com/blog/how-use-sql-hadoop-drill-rest-json-nosql-and-hbase-simple-rest-client > > > > > > > > > > > > > > 0: jdbc:drill:> use dfs.mydata; > > > > > > > > > > > > > > create or replace view prodview as SELECT CAST(row_key AS > > INTEGER) > > > AS > > > > > > > prod_id, CAST(t.details.category AS VARCHAR(40)) AS category, > > > > > > > CAST(t.details.name AS VARCHAR(129)) AS name FROM > > maprdb.products > > > t; > > > > > > > > > > > > > > > > > > > > > On Tue, Jul 28, 2015 at 11:35 AM, Usman Ali < > > > > [email protected] > > > > > > > > > > > > > wrote: > > > > > > > > > > > > > > > Hi, > > > > > > > > When we query an Hbase table like "select * from > > > > > > > > hbasePluginName.`tableName`" using Restful APIs, the json it > > > > returns > > > > > > > > contains values in the form of bytes. I know that all the > > values > > > > in > > > > > my > > > > > > > > hbase table were originally of String form but I do not know > > > exact > > > > > > schema > > > > > > > > (column families and column names) of my table. How can I > > convert > > > > > those > > > > > > > > bytes stored in strings back to my original strings. > > > > > > > > > > > > > > > > Thanks. > > > > > > > > Usman Ali > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- Abdelhakim Deneche Software Engineer <http://www.mapr.com/> Now Available - Free Hadoop On-Demand Training <http://www.mapr.com/training?utm_source=Email&utm_medium=Signature&utm_campaign=Free%20available>
