In Periodic.iterate statement , getting failed count under operations

Hi Team,

I am using apoc.periodic.iterate for loading the data. I am getting some count under operations like below
{
"total": 15620389,
"committed": 15618389,
"failed": 1000,
"errors": {

}
}

Want to understand the significance of above values and parameters.

Query used is -

CALL apoc.periodic.iterate('
with "jdbc:oracle:thin:aa/vvv@1.2.3.4:1522/XCOMSTB2" as url
CALL apoc.load.jdbc(url,"select * from tab.PORT_V WHERE EQUIP_TYPE IN
('STB',
'OLT')") YIELD row return row','
MERGE (POmw:PORT { PORT_CI_NAME: REPLACE(row.PORT_CI_NAME,'\"','') })
ON CREATE SET
POmw.PORT_NAME=REPLACE(row.PORT_NAME,'\"',''),
POmw.PORT_PKEY=REPLACE(row.PORT_PKEY,'\"',''),
POmw.MARKFORDEL='N',
POmw.CREATED_DATE=apoc.temporal.format(datetime(), "dd-MM-YYYY HH:mm:ss")
ON MATCH SET
POmw.PORT_NAME=REPLACE(row.PORT_NAME,'\"',''),
POmw.PORT_PKEY=REPLACE(row.PORT_PKEY,'\"',''),
POmw.MARKFORDEL='N',
POmw.MODIFIED_DATE=apoc.temporal.format(datetime(), "dd-MM-YYYY HH:mm:ss")', {batchSize:1000, iterateList:true, retries:3,parallel:true})
YIELD batches, total ,timeTaken , failedOperations , failedBatches , errorMessages , committedOperations , operations
RETURN batches, total ,timeTaken , failedOperations , failedBatches , errorMessages , committedOperations , operations;

Regards
Akshat

This means that there are 15620389 rows generated by the first statement, of which 15618389 of them completed the second statement and the rest 1000 failed for whatever reason.