java-driver
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Option to report trace only once during pagination
Fixes CASSJAVA-71.
Currently, when client executes below code:
ResultSet rs = session.execute(SimpleStatement.newInstance("select * from kv").setPageSize(2).setTracing(true));
Iterator<Row> iter = rs.iterator();
while (iter.hasNext()) {
iter.next();
}
The following trace events are generated:
cqlsh> select session_id, command, coordinator, duration, parameters, started_at from system_traces.sessions;
session_id | command | coordinator | duration | parameters | started_at
--------------------------------------+---------+-------------+----------+-------------------------------------------------------------------------------------------------------------------------+---------------------------------
f69b1c00-e7d7-11ef-911d-0b57c0dc9621 | QUERY | 127.0.0.1 | 1255 | {'consistency_level': 'LOCAL_ONE', 'page_size': '2', 'query': 'select * from kv', 'serial_consistency_level': 'SERIAL'} | 2025-02-10 17:53:41.312000+0000
f69c2d70-e7d7-11ef-911d-0b57c0dc9621 | QUERY | 127.0.0.1 | 918 | {'consistency_level': 'LOCAL_ONE', 'page_size': '2', 'query': 'select * from kv', 'serial_consistency_level': 'SERIAL'} | 2025-02-10 17:53:41.319000+0000
f69c5480-e7d7-11ef-911d-0b57c0dc9621 | QUERY | 127.0.0.1 | 638 | {'consistency_level': 'LOCAL_ONE', 'page_size': '2', 'query': 'select * from kv', 'serial_consistency_level': 'SERIAL'} | 2025-02-10 17:53:41.320000+0000
f69bdf50-e7d7-11ef-911d-0b57c0dc9621 | QUERY | 127.0.0.1 | 1119 | {'consistency_level': 'LOCAL_ONE', 'page_size': '2', 'query': 'select * from kv', 'serial_consistency_level': 'SERIAL'} | 2025-02-10 17:53:41.317000+0000
After disabling report-every-page-fetch, only first page generates trace event:
cqlsh> select session_id, command, coordinator, duration, parameters, started_at from system_traces.sessions;
session_id | command | coordinator | duration | parameters | started_at
--------------------------------------+---------+-------------+----------+-------------------------------------------------------------------------------------------------------------------------+---------------------------------
e8f6ad80-e7d7-11ef-911d-0b57c0dc9621 | QUERY | 127.0.0.1 | 1628 | {'consistency_level': 'LOCAL_ONE', 'page_size': '2', 'query': 'select * from kv', 'serial_consistency_level': 'SERIAL'} | 2025-02-10 17:53:18.424000+0000