yifan-c commented on code in PR #4458:
URL: https://github.com/apache/cassandra/pull/4458#discussion_r2495999305
##########
src/java/org/apache/cassandra/schema/SystemDistributedKeyspace.java:
##########
@@ -458,22 +458,78 @@ public static CompressionDictionary
retrieveLatestCompressionDictionary(String k
}
/**
- * Retrieves a specific compression dictionary for a given keyspace and
table.
+ * Retrieves the latest compression dictionary for a given keyspace and
table
+ * backed by {@link LightweightCompressionDictionary} object.
+ *
+ * @param keyspaceName the keyspace name to retrieve the dictionary for
+ * @param tableName the table name to retrieve the dictionary for
+ * @return the latest compression dictionary for the specified keyspace
and table,
+ * or null if no dictionary exists or if an error occurs during
retrieval
+ */
+ @Nullable
+ public static LightweightCompressionDictionary
retrieveLightweightLatestCompressionDictionary(String keyspaceName, String
tableName)
+ {
+ String query = "SELECT keyspace_name, table_name, kind, dict_id,
dict_checksum, dict_length FROM %s.%s WHERE keyspace_name='%s' AND
table_name='%s' LIMIT 1";
+ String fmtQuery = format(query,
SchemaConstants.DISTRIBUTED_KEYSPACE_NAME, COMPRESSION_DICTIONARIES,
keyspaceName, tableName);
+ try
+ {
+ return
CompressionDictionary.createFromRowLightweight(QueryProcessor.execute(fmtQuery,
ConsistencyLevel.ONE).one());
+ }
+ catch (Exception e)
+ {
+ return null;
+ }
+ }
+
+ /**
+ * Retrieves a specific compression dictionary for a given keyspace and
table
+ * backed by {@link LightweightCompressionDictionary} object.
*
* @param keyspaceName the keyspace name to retrieve the dictionary for
* @param tableName the table name to retrieve the dictionary for
* @param dictionaryId the dictionary id to retrieve the dictionary for
* @return the compression dictionary identified by the specified
keyspace, table and dictionaryId,
* or null if no dictionary exists or if an error occurs during
retrieval
*/
- public static CompressionDictionary retrieveCompressionDictionary(String
keyspaceName, String tableName, CompressionDictionary.DictId dictionaryId)
+ @Nullable
+ public static CompressionDictionary retrieveCompressionDictionary(String
keyspaceName, String tableName, long dictionaryId)
{
String query = "SELECT kind, dict_id, dict, dict_length, dict_checksum
FROM %s.%s WHERE keyspace_name='%s' AND table_name='%s' AND dict_id=%s";
- String fmtQuery = format(query,
SchemaConstants.DISTRIBUTED_KEYSPACE_NAME, COMPRESSION_DICTIONARIES,
keyspaceName, tableName, dictionaryId.id);
+ String fmtQuery = format(query,
SchemaConstants.DISTRIBUTED_KEYSPACE_NAME, COMPRESSION_DICTIONARIES,
keyspaceName, tableName, dictionaryId);
try
{
- UntypedResultSet.Row row = QueryProcessor.execute(fmtQuery,
ConsistencyLevel.ONE).one();
- return CompressionDictionary.createFromRow(row);
+ return
CompressionDictionary.createFromRow(QueryProcessor.execute(fmtQuery,
ConsistencyLevel.ONE).one());
+ }
+ catch (Exception e)
+ {
+ return null;
+ }
+ }
+
+ /**
+ * Retrieves all dictionaries for a given keyspace and table.
+ *
+ * @param keyspaceName the keyspace name to retrieve the dictionary for
+ * @param tableName the table name to retrieve the dictionary for
+ * @return the compression dictionaries identified by the specified
keyspace and table,
+ * or null if no dictionary exists or if an error occurs during
retrieval
+ */
+ @Nullable
+ public static List<LightweightCompressionDictionary>
retrieveLightweightCompressionDictionaries(String keyspaceName, String
tableName)
+ {
+ String query = "SELECT keyspace_name, table_name, kind, dict_id,
dict_length, dict_checksum, size FROM %s.%s WHERE keyspace_name='%s' AND
table_name='%s'";
+ String fmtQuery = format(query,
SchemaConstants.DISTRIBUTED_KEYSPACE_NAME, COMPRESSION_DICTIONARIES,
keyspaceName, tableName);
+ try
+ {
+ List<LightweightCompressionDictionary> dictionaries = new
ArrayList<>();
+ UntypedResultSet result = QueryProcessor.execute(fmtQuery,
ConsistencyLevel.ONE);
Review Comment:
nit: could delay the creation of array list.
```suggestion
UntypedResultSet result = QueryProcessor.execute(fmtQuery,
ConsistencyLevel.ONE);
if (result.isEmpty())
return Collections.emptyList();
List<LightweightCompressionDictionary> dictionaries = new
ArrayList<>();
```
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