looks like a good use case created and improvement request
https://issues.apache.org/jira/browse/HIVE-2980 On Tue, Apr 24, 2012 at 9:10 AM, Sukhendu Chakraborty < sukhendu.chakrabo...@gmail.com> wrote: > Thanks Nitin. I am aware of what Hive is doing. The question is, is it > okay not return an error/warning when no data is found since the > metadata for the table also contains the data location when you create > the table (which creates the hdfs directory as well). So, if somebody > erroneously removes the hive directory corr. to the table, atleast a > warning on select might be a good idea. > > -Sukhendu > > On Mon, Apr 23, 2012 at 8:28 PM, Nitin Pawar <nitinpawar...@gmail.com> > wrote: > > hive table meta data is stored into a meta data store which will retain > the > > table structure and other meta info even if you delete hdfs table > directory > > as its stored in metadata store db. > > > > When you do a select * from table; > > 1) hive checks for table exists in metadata store > > 2) if table is existing then check the location of data > > 3) if data is available in the location process the data else return OK > > without doing anything > > > > It is not an error case because hive job did not fail. > > > > > > On Tue, Apr 24, 2012 at 6:25 AM, Sukhendu Chakraborty > > <sukhendu.chakrabo...@gmail.com> wrote: > >> > >> I have a hive table tab3 with two columns (c1 int, c2 int) > >> > >> hive> load data local inpath '/tmp/orhc466fb981' into table tab3; > >> Copying data from file:/tmp/orhc466fb981 > >> Copying file: file:/tmp/orhc466fb981 > >> Loading data to table default.tab3 > >> OK > >> Time taken: 3.907 seconds > >> hive> select * from tab3; > >> OK > >> 4 2 > >> 4 10 > >> 7 4 > >> 7 22 > >> ..... > >> //remove the tab3 directory from hdfs > >> [schakrab@diy-1-2 orch]$ hadoop fs -rmr /user/hive/warehouse/tab3; > >> Deleted hdfs://localhost:9000/user/hive/warehouse/tab3 > >> [schakrab@diy-1-2 orch]$ hive > >> Hive history > >> file=/tmp/schakrab/hive_job_log_schakrab_201204231748_1985146177.txt > >> //no error thrown! > >> hive> select * from tab3; > >> OK > >> Time taken: 3.68 seconds > >> // of course. metadata still exists. > >> hive> desc tab3; > >> OK > >> c1 int > >> c2 int > >> Time taken: 0.127 seconds > >> > >> // doing another load recreates the directory tab3 > >> > >> Shouldn't the select * query return an error when the underlying table > >> file is removed ? > >> > >> -Sukhendu > > > > > > > > > > -- > > Nitin Pawar > > > -- Nitin Pawar
