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https://issues.apache.org/jira/browse/PHOENIX-914?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13961530#comment-13961530
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Vladimir Rodionov commented on PHOENIX-914:
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{quote}
Also, some skew would exist between the HBase timestamp and the timestamp in
the row key
{quote}
The idea is to map one column from the table (of compatible type: TIMESTAMP,
DATE) to HBase cell's timestamp and to use Scan with timestamp ranges in a
queries if we detect this *mapped* column in a WHERE clause. Which skew are you
talking about, James? This column, physically, will not exists in a HBase table
- its rowkey value's timestamp.
INSERT INTO ods.events (metricid, nvalue, time) VALUES( 'X', '150',
'13907665544') will be translated
into Put operation with 2 column qualifiers 'metricid', 'nvalue' and Put's
timestamp= 13907665544.
Put put = new Put(some_row_key)
put.add(family, 'metricid'.getBytes(), 13907665544, 'X'.getBytes());
etc
> Native HBase timestamp support to optimize date range queries in Phoenix
> -------------------------------------------------------------------------
>
> Key: PHOENIX-914
> URL: https://issues.apache.org/jira/browse/PHOENIX-914
> Project: Phoenix
> Issue Type: Improvement
> Affects Versions: 4.0.0
> Reporter: Vladimir Rodionov
> Assignee: Vladimir Rodionov
>
> For many applications one of the column of a table can be (and must be)
> naturally mapped
> to HBase timestamp. What it gives us is the optimization on StoreScanner
> where HFiles with timestamps out of range of
> a Scan operator will be omitted. Let us say that we have time-series type of
> data (EVENTS) and custom compaction, where we create
> series of HFiles with continuous non-overlapping timestamp ranges.
> CREATE TABLE IF NOT EXISTS ODS.EVENTS (
> METRICID VARCHAR NOT NULL,
> METRICNAME VARCHAR,
> SERVICENAME VARCHAR NOT NULL,
> ORIGIN VARCHAR NOT NULL,
> APPID VARCHAR,
> IPID VARCHAR,
> NVALUE DOUBLE,
> TIME TIMESTAMP NOT NULL /+ TIMESTAMP +/,
> DATA VARCHAR,
> SVALUE VARCHAR
> CONSTRAINT PK PRIMARY KEY (METRICID, SERVICENAME, ORIGIN, APPID, IPID,
> TIME)
> ) SALT_BUCKETS=40, IMMUTABLE_ROWS=true,VERSIONS=1,DATA_BLOCK_ENCODING='NONE';
> Make note on TIME TIMESTAMP NOT NULL /+ TIMESTAMP +/ - this is the Hint to
> Phoenix that the column
> TIME must be mapped to HBase timestamp.
> The Query:
> Select all events of type 'X' for last 7 days
> SELECT * from EVENTS WHERE METRICID = 'X' and TIME < NOW() and TIME > NOW() -
> 7*24*3600000; (this may be not correct SQL syntax of course)
> These types of queries will be efficiently optimized if:
> 1. Phoenix maps TIME column to HBase timestamp
> 2. Phoenix smart enough to map WHERE clause on TIME attribute to Scan
> timerange
> Although this :
> Properties props = new Properties();
> props.setProperty(PhoenixRuntime.CURRENT_SCN_ATTRIB, Long.toString(ts));
> Connection conn = DriverManager.connect(myUrl, props);
> conn.createStatement().execute("UPSERT INTO myTable VALUES ('a')");
> conn.commit();
> will work in my case- it may not be efficient from performance point of view
> because for every INSERT/UPSERT
> new Connection object and new Statement is created, beside this we still need
> the optimization 2. (see above).
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