/* get the value stored in the first element */
void*
DLGetTailVal(Dllist* l)
{
Dlelem* e = DLGetTail(l);
return (e ? e->dle_val : 0);
}
/*
* CatalogCacheCreateEntry
* Create a new CatCTup entry, copying the given HeapTuple and other
* supplied data into it. The new entry is given refcount 1.
*/
static CatCTup *
CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp,
uint32 hashValue, Index hashIndex, bool negative)
{
CatCTup *ct;
MemoryContext oldcxt;
/*
* Allocate CatCTup header in cache memory, and copy the tuple there
* too.
*/
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
ct = (CatCTup *) palloc(sizeof(CatCTup));
heap_copytuple_with_tuple(ntp, &ct->tuple);
MemoryContextSwitchTo(oldcxt);
/*
* Finish initializing the CatCTup header, and add it to the cache's
* linked lists and counts.
*/
ct->ct_magic = CT_MAGIC;
ct->my_cache = cache;
DLInitElem(&ct->lrulist_elem, (void *) ct);
DLInitElem(&ct->cache_elem, (void *) ct);
ct->c_list = NULL;
ct->refcount = 1; /* count this first reference */
ct->dead = false;
ct->negative = negative;
ct->hash_value = hashValue;
DLAddHead(&CacheHdr->ch_lrulist, &ct->lrulist_elem);
DLAddHead(&cache->cc_bucket[hashIndex], &ct->cache_elem);
cache->cc_ntup++;
CacheHdr->ch_ntup++;
/*
* If we've exceeded the desired size of the caches, try to throw away
* the least recently used entry. NB: the newly-built entry cannot
* get thrown away here, because it has positive refcount.
*/
if (CacheHdr->ch_ntup > CacheHdr->ch_maxtup)
{
Dlelem *elt,
*prevelt;
for (elt = DLGetTail(&CacheHdr->ch_lrulist); elt; elt = prevelt)
{
CatCTup *oldct = (CatCTup *) DLE_VAL(elt);
prevelt = DLGetPred(elt);
if (oldct->refcount == 0)
{
CACHE2_elog(DEBUG2, "CatCacheCreateEntry(%s): Overflow, LRU removal",
cache->cc_relname);
#ifdef CATCACHE_STATS
oldct->my_cache->cc_discards++;
#endif
CatCacheRemoveCTup(oldct->my_cache, oldct);
if (CacheHdr->ch_ntup <= CacheHdr->ch_maxtup)
break;
}
}
}
return ct;
}