// Cleanup NARoutine cache after the statement completes. Remove entries
// using LRU policy, if the cache has grown too large. The approach here is
// somewhat different from NATableDB caching, which deletes entries from the
// NATable cache if the statement was DDL that may have affected the table
// definition. NATable caching also deletes tables from the cache at this
// time for performance reasons.
void NARoutineDB::resetAfterStatement()
{
// Delete 'dirty' NARoutine objects that were not deleted earlier
// to save compile-time performance.
if (routinesToDeleteAfterStatement_.entries())
{
// Clear the list of tables to delete after statement
routinesToDeleteAfterStatement_.clear();
}
if (entries())
{
// Reduce size of cache if it has grown too large.
if (!enforceMemorySpaceConstraints())
cacheMetaData_ = FALSE; // Disable cache if there is a problem.
// Reset statement level flags
refreshCacheInThisStatement_=FALSE;
// Clear 'accessed in current statement' flag for all cached NARoutines.
NAHashDictionaryIterator<NARoutineDBKey,NARoutine> iter (*this);
NARoutineDBKey *key;
NARoutine *routine;
iter.getNext(key,routine);
while(key) {
routine->getAccessedInCurStmt() = FALSE;
iter.getNext(key,routine);
}
}
}
// Find the NARoutine entry in the cache for 'key' or create it if not found.
// 1. Check for entry in cache.
// 2. If it doesn't exist, return.
// 3. If it does exist, check to see if this is first time entry accessed.
// 4. If so, check to see if entry is dirty (obsolete).
// 5. If dirty, remove key and add to list to remove entry after statement
// completes.
// Note that BindWA is needed to be passed to this function so that we can
// use it with getRedefTime() is necessary.
NARoutine *NARoutineDB::get(BindWA *bindWA, const NARoutineDBKey *key)
{
// Check cache to see if a cached NARoutine object exists
NARoutine *cachedNARoutine =
NAKeyLookup<NARoutineDBKey,NARoutine>::get(key); /* 1 */
totalLookupsCount_++; // Statistics counter: number of lookups
if (!cachedNARoutine || !cacheMetaData_) return NULL; /* 2 */
totalCacheHits_++; // Statistics counter: number of cache hits.
// Record time that this NARoutine was obtained from cache for LRU.
cachedNARoutine->setLastUsedTime(hs_getEpochTime());
cachedNARoutine->getAccessedInCurStmt() = TRUE;
return cachedNARoutine;
}