Very simple example - one table, one index, one query: CREATE TABLE book ( id bigserial NOT NULL, "year" integer, -- other columns... ); CREATE INDEX book_year_idx ON book (year) EXPLAIN SEL...

I have a HBase table, and I need to get the result from several ranges. For example, I may need get data from different ranges like row 1-6, 100-150,..... I know that for each scan, I can define th...

I am designing an app to run on hbase and want to interactively explore the contents of my cluster. I am in the hbase shell and I want to perform a scan of all keys starting with the chars "abc". S...

I don't know why it's very slow if I use prefixfilter to query. Can someone explain which is the best way to query HBase, thanks. hbase(main):002:0> scan 'userlib',{FILTER=>org.apache.hadoop...

I am performing a range scan that is giving me 500k records. If I set scan.setCaching(100000) it took less than one second, but if scan.setCaching(100000) is not set it took nearly 38 sec. If I se...

we would like to filter a scan on a HBase table with two QualifierFilters. Means we would like to only get the rows of the table which do have a certain column 'col_A' AND (!) a certain other colum...

Simple question, but I haven't found a good explanation on google. When using Set Statistics IO ON, the logical reads and scan count is provided in the message window of management studio. If I hav...

How does HBase performs a lookup and retrieves a record ? e.g., what is the equivalent in HBase for the RDBMS's B-Trees? [EDIT] I understand how HBase resolves the -ROOT-, and .META. tables to fi...

I'm trying to use a Scan operation on a DynamoDB table to match items with given 'tags'. The tags for an item are stored in a single set attribute. E.g.: machine-1: tags = "windows", "iis", "64bit...