[jboss-user] [Performance Tuning] - read-ahead cache invalidate before any data access
Hi,
I am trying to implement a read-ahead on-find strategy for a CMP bean using jboss 4.0.2.
The finder method appears to cache all the required data and return a collection of local
objects with cached data as evidenced by log output like
2008-06-26 07:13:43,875 DEBUG
[org.jboss.ejb.plugins.cmp.jdbc.JDBCEJBQLQuery.StockData#findByPing] Executing SQL: SELECT
DISTINCT t0_o.id, t0_o.ticker, t0_o.name, t0_o.currency, t0_o.quote, t0_o.open, t0_o.high,
t0_o.low, t0_o.delta, t0_o.volume, t0_o.marketcap, t0_o.range, t0_o.divdate,
t0_o.divyield, t0_o.exchange, t0_o.divrate, t0_o.pubdate, t0_o.provider, t0_o.updated FROM
stockdata t0_o LEFT OUTER JOIN stockping t1_o_ping ON t0_o.id=t1_o_ping.id WHERE
t1_o_ping.ping > ? AND t0_o.quote IS NOT NULL
2008-06-26 07:13:43,875 TRACE
[org.jboss.ejb.plugins.cmp.jdbc.JDBCEJBQLQuery.StockData#findByPing] param: i=1,
type=INTEGER, value=20240053
2008-06-26 07:13:43,875 TRACE
[org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCCMP2xFieldBridge.StockData#id] result: i=1,
type=java.lang.Integer, value=36
2008-06-26 07:13:43,875 TRACE
[org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCCMP2xFieldBridge.StockData#ticker] result: i=2,
type=java.lang.String, value=USTYN
2008-06-26 07:13:43,875 TRACE [org.jboss.ejb.plugins.cmp.jdbc.ReadAheadCache.StockData]
Add preload data: entity=StockData pk=36 field=ticker
However, when I call the value method for each of the local objects in the collection I
get:
2008-06-26 08:02:00,437 TRACE [org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.StockData]
RESET PERSISTENCE CONTEXT: id=36
2008-06-26 08:02:00,437 TRACE [org.jboss.ejb.plugins.cmp.jdbc.ReadAheadCache.StockData]
load data: entity=StockData pk=36
2008-06-26 08:02:00,437 TRACE [org.jboss.ejb.plugins.cmp.jdbc.ReadAheadCache.StockData] No
preload data found: entity=StockData pk=36
2008-06-26 08:02:00,437 TRACE
[org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCEntityBridge.StockData] Default eager-load for
entity: readahead=null
2008-06-26 08:02:00,437 DEBUG
[org.jboss.ejb.plugins.cmp.jdbc.JDBCLoadEntityCommand.StockData] Executing SQL: SELECT
ticker, name, currency, quote, open, high, low, delta, volume, marketcap, range, divdate,
divyield, exchange, divrate, pubdate, provider, updated FROM stockdata WHERE (id=?)
2008-06-26 08:02:00,437 TRACE
[org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCCMP2xFieldBridge.StockData#id] param: i=1,
type=INTEGER, value=36
This indicates to me that all the cached data is tossed out and reloaded.
The method invoked is running as a transaction and consists essentially of
Collection coll = StockDataUtil.getLocalHome().findByPing(currMinutes);
for (Iterator i = coll.iterator(); i.hasNext(); )
{
StockDataLocal sdl = (StockDataLocal)i.next();
StockUpdateValue val = sdl.getUpdateValue();
stockMap.add(val);
}
Any help would be appreciated.
Dave Salmon
FreeRange Communications, Inc
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