Select statement generate alot of Redo

Hello DBAs,

I have a query that take along time. I don't see an issue with the Exec plan and the cost.

however, in the stats Redo Size is large. It is just a SELECT statement (no "for update")

what cause the Redo Size? Please see below.

Any help would be greatly appreciated.

SYS@pfsmnp4_1 > l

 1 SELECT this_.WORK_INSTRUCTION_ID    AS y0_

 2     FROM PFS_USAGE_ITEM_DTLS_011 this_

 3          INNER JOIN PFS_WORK_INSTRUCTIONS_011 workinstru1_

 4              ON this_.WORK_INSTRUCTION_ID = workinstru1_.ID

 5          INNER JOIN PFS_ROUTES_011 r2_ ON workinstru1_.ROUTE_ID = r2_.ID

 6    WHERE    this_.PLACEMENT_TYPE = 'MACHINE'

 7           AND r2_.ID IN