I would be curious to know the performance curve for let's say 20K, 40K
, 60K, 80K, 100K records. And what sort of indexing you have, whether
or not it's clustered, re-built and so on.
One could envision partitioning the status table such that recent
records were grouped together (on the assumption that they will be most
frequently "reported").
wkipj...@gmail.com wrote:
I have the following senario.
I have a tracking system. The system will record the status of an
object regularly, all the status records are stored in one table. And
it will keep a history of maximum 1000 status record for each object
it tracks. The maximum objects the system will track is 100,000. Which
means I will potentially have a table size of 100 million records.
I have to generate a report on the latest status of all objects being
tracked at a particular point in time, and also I have to allow user
to sort and filter on different columes in the status record displayed
in the report.
The following is a brief description in the status record (they are
not actual code)
ObjectRecord(
objectId bigint PrimaryKey
desc varchar
)
StatusRecord (
id bigint PrimaryKey
objectId bigint indexed
datetime bigint indexed
capacity double
reliability double
efficiency double
)
I have tried to do the following, it works very well with around
20,000 objects. (The query return in less than 10s) But when I have
100,000 objects it becomes very very slow. (I don't even have patience
to wait for it to return.... I kill it after 30 mins)
select * from statusrecord s1 INNER JOIN ( SELECT objectId ,
MAX(datetime) AS msdt FROM statusrecord WHERE startDatetime <=
1233897527657 GROUP BY objectId ) AS s2 ON ( s1.objectId = s2.objectId
AND s1.datetime = s2.msdt ) where ( capacity < 10.0 ) order by
s1.datetime DESC, s1.objectId DESC;
I did try to write a store procedure like below, for 100,000 objects
and 1000 status records / object, it returns in around 30 mins.
CREATE OR REPLACE FUNCTION getStatus(pitvalue BIGINT) RETURNS SETOF
statusrecord AS $BODY$
DECLARE
id VARCHAR;
status statusrecord%ROWTYPE;
BEGIN
FOR object IN SELECT * FROM objectRecord
LOOP
EXECUTE 'SELECT * FROM statusrecord WHERE objectId = ' ||
quote_literal(object.objectId) ||
' AND datetime <= ' || quote_literal(pitvalue) || ' ORDER BY datetime
DESC'
INTO status;
IF FOUND THEN
RETURN NEXT status;
END IF;
END LOOP;
RETURN;
END
$BODY$ LANGUAGE plpgsql;
Just wanna to know if anyone have a different approach to my senario.
Thanks alot.
John
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