HashMapWrapper<MapJoinObjectKey, MapJoinObjectValue> hashTable = mapJoinTables.get(alias);
MapJoinObjectKey keyMap = new MapJoinObjectKey(metadataKeyTag, key);
MapJoinObjectValue o = hashTable.get(keyMap);
RowContainer res = null;
boolean needNewKey = true;
if (o == null) {
int bucketSize = HiveConf.getIntVar(hconf, HiveConf.ConfVars.HIVEMAPJOINBUCKETCACHESIZE);
res = new RowContainer(bucketSize);
res.add(value);
} else {
res = o.getObj();
res.add(value);
// If key already exists, HashMapWrapper.get() guarantees it is already in main memory HashMap
// cache. So just replacing the object value should update the HashMapWrapper. This will save
// the cost of constructing the new key/object and deleting old one and inserting the new one.
if ( hashTable.cacheSize() > 0) {
o.setObj(res);
needNewKey = false;
}
}
if (metadataValueTag[tag] == -1) {
metadataValueTag[tag] = nextVal++;
tableDesc valueTableDesc = conf.getValueTblDescs().get(tag);
SerDe valueSerDe = (SerDe)ReflectionUtils.newInstance(valueTableDesc.getDeserializerClass(), null);
valueSerDe.initialize(null, valueTableDesc.getProperties());
mapMetadata.put(Integer.valueOf(metadataValueTag[tag]),
new MapJoinObjectCtx(
ObjectInspectorUtils.getStandardObjectInspector(valueSerDe.getObjectInspector(),
ObjectInspectorCopyOption.WRITABLE),
valueSerDe, valueTableDesc, hconf));
}
// Construct externalizable objects for key and value
if ( needNewKey ) {
MapJoinObjectKey keyObj = new MapJoinObjectKey(metadataKeyTag, key);
MapJoinObjectValue valueObj = new MapJoinObjectValue(metadataValueTag[tag], res);
valueObj.setConf(hconf);
// This may potentially increase the size of the hashmap on the mapper
if (res.size() > mapJoinRowsKey) {
if ( res.size() % 100 == 0 ) {
LOG.warn("Number of values for a given key " + keyObj + " are " + res.size());
LOG.warn("used memory " + Runtime.getRuntime().totalMemory());
}
}
hashTable.put(keyObj, valueObj);
}