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https://issues.jboss.org/browse/TEIID-2627?page=com.atlassian.jira.plugin...
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Ramesh Reddy commented on TEIID-2627:
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Accumulo has concept of tables, and it is a key/value store. A key structure is looks like
||rowid|| Column Family(CF)||Column Qualifier(CQ)||Timestamp||
||rowid||VALUE||
Based on the above a table structure could be derived that could work in SQL world, where
rowid = becomes a identity column , which is PK
CF/CQ = together or CF alone can become the column name in table
CQ/VALUE = one of them will be values of the column.
This is basis how a table is formed in Accumulo. One caveat is the column type will be
always byte[]. However, if user modeled their schema in Teiid to start with, Teiid will
convert back and forth between byte[] and defined data type when data is going back and
forth between queries.
If the user uses equality or IN predicate on the ROWID column, then it will be converted
to Range based query navigation. If user uses different column for predicate , then a
iterator is pushed in to the tablet servers that more or less do a table scan. Teiid query
engine's evalution engine is fitted for this task, so this translator can support
variety of SQL criteria on single table. Since Teiid engine is in Accumulo, it will be
filtering out data much earlier in query cycle.
Since all the Accumulo design happens in context of single table, no JOIN capabilities at
source will be supported, they will be handled by Teiid engine entirely. This translator
will also support the insert/update/delete along with select.
todo: still need to implement inverted index table on the columns that are defined as
index columns in metadata for faster access during querying.
Accumulo as a Supported Data Source
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Key: TEIID-2627
URL:
https://issues.jboss.org/browse/TEIID-2627
Project: Teiid
Issue Type: Feature Request
Components: Connector API
Affects Versions: 8.6
Reporter: devin pinkston
Assignee: Ramesh Reddy
Labels: accumulo, data_source
Fix For: Open To Community
Support for Accumulo as a data source in Teiid. Would require Resource Adapter and
Translator development.
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