tolbertam commented on code in PR #3917:
URL: https://github.com/apache/cassandra/pull/3917#discussion_r2076685870
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src/java/org/apache/cassandra/db/SystemKeyspace.java:
##########
@@ -1863,16 +1864,37 @@ public static void resetPreparedStatements()
}
public static int loadPreparedStatements(TriFunction<MD5Digest, String,
String, Boolean> onLoaded)
+ {
+ return loadPreparedStatements(onLoaded,
QueryProcessor.PRELOAD_PREPARED_STATEMENTS_FETCH_SIZE);
+ }
+
+ public static int loadPreparedStatements(TriFunction<MD5Digest, String,
String, Boolean> onLoaded, int pageSize)
{
String query = String.format("SELECT prepared_id, logged_keyspace,
query_string FROM %s.%s", SchemaConstants.SYSTEM_KEYSPACE_NAME,
PREPARED_STATEMENTS);
- UntypedResultSet resultSet = executeOnceInternal(query);
+ UntypedResultSet resultSet = executeOnceInternalWithPaging(query,
pageSize);
int counter = 0;
+ long initialStatementsEvicted =
QueryProcessor.metrics.preparedStatementsEvicted.getCount();
for (UntypedResultSet.Row row : resultSet)
{
if
(onLoaded.accept(MD5Digest.wrap(row.getByteArray("prepared_id")),
row.getString("query_string"),
row.has("logged_keyspace") ?
row.getString("logged_keyspace") : null))
counter++;
+
+ if (counter % pageSize == 0 &&
QueryProcessor.isPreparedStatementCacheFull())
+ {
+ // In the event that we detect that the prepared statement
cache has filled up, return early to prevent
Review Comment:
I think it doesn't have to be too precise. We may in fact page several
times more than what would be ideal, but the important thing is that we stop
and don't page indefinitely.
We could make it more sensitive by changing the calculation to be some value
less than the maximum weight (something like 95%). The downside of doing that
is we may drop prepared statements that we may have been able to cache
otherwise and would also notify the user that the cache may be leaky when it in
fact that isn't the issue.
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