[
https://issues.apache.org/jira/browse/PHOENIX-914?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jeffrey Zhong updated PHOENIX-914:
----------------------------------
Attachment: PHOENIX-914.patch
This patch exposes HBase timestamp as a query hint. The reason is that HBase
scan time range only supports query against [minTimeStamp, maxTimeStamp) so
it's quite matching select hint behavior.
The reason we don't bound this value with another real column is that it's
better not to make underling cell timestamp writable to an external client
because it may complicate later transaction implementations.
The current patch is simple and non-intrusive. If there is a better way in
future, we can easily replace this one.
Thanks,
-Jeffrey
> 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: Jeffrey Zhong
> Attachments: PHOENIX-914.patch
>
>
> 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).
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
