partitioning

I am building a dictionary on a hadoop cluster and need to generate a numeric id for each token. How should I do it? You have two problems. First you want to make sure that you assign exactly one id for each token. To do that you should sort and group records by token and make the assignment in a reducer. Once you've made sure that the reducer method is called exactly once for each token you can use the partition number from the context and a unique numeric id maintained by the reducer (one instance per partition) - just use an instance variable initialized to 1 in the setup method and

Is there a simple (ie. non-hacky) and race-condition free way to create a partitioned sequence in PostgreSQL. Example: Using a normal sequence in Issue: | Project_ID | Issue | | 1 | 1 | | 1 | 2 | | 2 | 3 | | 2 | 4 | Using a partitioned sequence in Issue: | Project_ID | Issue | | 1 | 1 | | 1 | 2 | | 2 | 1 | | 2 | 2 | I do not believe there is a simple way that is as easy as regular sequences, because: A sequence stores only one number stream (next value, etc.). You want one for each partition. Sequences have special handling that bypasses the current transaction (to avoid the race condition).

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 working on fleet management. I am having large amount of writes on a location table with following columns date time vehicle no. long latitude speed userid (which is foreign key...) Here this table is going to have write operation every 3 sec. Hence there will be millions of record in it. So to retrieve faster data I AM PLANNING Partition. Now my question:- How to handle foreign key? I heard that partition does not support foreign key Which column should be used for partition. is it necessary to have unique key as a partition column. There will be trillions of record @rc-Thanks man..what

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