I've got a funny feeling both of the ignore_dupe_keys on the indexes is causing records to be spat out of the tables on insert:

Add a select above your insert and have a look at the values being returned:

SELECT place_id, data_id

FROM @rules r

INNER JOIN @data_table pp ON r.property_id = pp.property_id

ORDER BY place_id, r.property_id

INSERT INTO #tmp (place_id, data_id)

SELECT place_id, data_id

FROM @rules r

INNER JOIN @data_table pp ON r.property_id = pp.property_id

ORDER BY place_id, r.property_id

SELECT [place_id], [data_id]

FROM #tmp

I think what's happening is if a duplicate row is found both of the records are being spat from the tables as per the below. Weird hey!!!

/*

--can't have a duplicate place_id

--can't have a duplicate data_id

place_id, data_id

110 --No duplicate

120 --Duplicate place_id (spit the row from the @rules table, 2,3,4 left, also spit 20)

230 --No duplicate

240 --Duplicate place_id (spit the row from the @rules table, 3,4 left, also spit 40)

310 --Duplicate data_id (spit the row from the @rules table 4 left, also spit 10)

320 --(20 doesn't exist in the @data_table anymore so nothing to join on)

410 --Duplicate data_id (spit 4 from the @rules table. nothing left in the table.)

420 --table empty

430 --Duplicate data_id

440 --table empty

*/