Wail Y. Alkowaileet created ASTERIXDB-3180:
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Summary: Apply filter before assembling columnar datasets
Key: ASTERIXDB-3180
URL: https://issues.apache.org/jira/browse/ASTERIXDB-3180
Project: Apache AsterixDB
Issue Type: Improvement
Components: COMP - Compiler, RT - Runtime
Affects Versions: 0.9.9
Reporter: Wail Y. Alkowaileet
Assignee: Wail Y. Alkowaileet
Fix For: 0.9.9
The idea here is to examine column(s) in the WHERE clause before record
assembly (Mike Carey refers to this approach as "poor man's index"). The
sequence could be summarized as follows:
* We first read the filtering columns (i.e., columns in the WHERE clause)
* If the column(s)
** satisfy the query predicate, we read the rest of the requested columns and
we assemble the record
** If not, we simply fetch the next tuple
This approach can improve the I/O (by skip reading columns if possible) and
also avoid assembling records that will be filtered anyway – a wasted CPU
expense
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