database-partitioning

All: I have a data frame like the follow.I know I can do a global rank order like this: dt <- data.frame( ID = c('A1','A2','A4','A2','A1','A4','A3','A2','A1','A3'), Value = c(4,3,1,3,4,6,6,1,8,4) ); > dt ID Value 1 A1 4 2 A2 3 3 A4 1 4 A2 3 5 A1 4 6 A4 6 7 A3 6 8 A2 1 9 A1 8 10 A3 4 dt$Order <- rank(dt$Value,ties.method= "first") > dt ID Value Order 1 A1 4 5 2 A2 3 3 3 A4 1 1 4 A2 3 4 5 A1 4 6 6 A4 6 8 7 A3 6 9 8 A2 1 2 9 A1 8 10 10 A3 4 7 But how can I set a rank order for a particular ID instead of a global rank order. How can I get this done? In T-SQL, we can get this done as the following

Can I partition a Hive table upon insert by an existing field? I have a 10 GB file with a date field and an hour of day field. Can I load this file into a table, then insert-overwrite into another partitioned table that uses those fields as a partition? Would something like the following work? INSERT OVERWRITE TABLE tealeaf_event PARTITION(dt=evt.datestring,hour=evt.hour) SELECT * FROM staging_event evt; Thanks! Travis I just ran across this trying to answer the same question and it was helpful but not quite complete. The short answer is yes, something like the query in the question will work

I am trying to partition an existing table in Oracle 12C R1 using below SQL statement. ALTER TABLE TABLE_NAME MODIFY PARTITION BY RANGE (DATE_COLUMN_NAME) INTERVAL (NUMTOYMINTERVAL(1,'MONTH')) ( PARTITION part_01 VALUES LESS THAN (TO_DATE('01-SEP-2017', 'DD-MON-RRRR')) ) ONLINE; Getting error: Error report - SQL Error: ORA-14006: invalid partition name 14006. 00000 - "invalid partition name" *Cause: a partition name of the form <identifier> is expected but not present. *Action: enter an appropriate partition name. Partition needs to be done on the basis of data datatype column with the

I'm undecided whether it's better, performance-wise, to use a very commonly shared column value (like Country ) as partition key for a compound primary key or a rather unique column value (like Last_Name ). Looking at Cassandra 1.2's documentation about indexes I get this: " When to use an index : Cassandra's built-in indexes are best on a table having many rows that contain the indexed value. The more unique values that exist in a particular column, the more overhead you will have, on average, to query and maintain the index. For example, suppose you had a user table with a billion users and

I want to partition a mysql table by datetime column. One day a partition.The create table scripts is like this: CREATE TABLE raw_log_2011_4 ( id bigint(20) NOT NULL AUTO_INCREMENT, logid char(16) NOT NULL, tid char(16) NOT NULL, reporterip char(46) DEFAULT NULL, ftime datetime DEFAULT NULL, KEY id (id) ) ENGINE=InnoDB AUTO_INCREMENT=286802795 DEFAULT CHARSET=utf8 PARTITION BY hash (day(ftime)) partitions 31; But when I select data of some day.It could not locate the partition.The select statement is like this: explain partitions select * from raw_log_2011_4 where day(ftime) = 30; when i use