Query Oracle for new data based on properties of visible markers?

Question

I'm very new to R/Shiny/Leaflet.

I have a barebones working example where I can display points on map based on their lat/long in a table I pull from Oracle:

siteData <- conn %>% tbl(in_schema("SCHEMANAME", "TABLENAME")) %>% as.data.frame();

function(input, output, session) {
  output$map <- renderLeaflet({
    leaflet() %>%
      addTiles() %>%
      setView(lng = -93.85, lat = 37.45, zoom = 4)
  })
...
  observe({
    colorBy <- input$color
    sizeBy <- input$size
    
    
    leafletProxy("map", data = siteData) %>%
      clearMarkers() %>%
      addCircleMarkers(~LONGITUDE, ~LATITUDE,
                       popup=
                         ~paste("ID: ", as.character(ID), "<br>",
                                "Latitude: ", as.character(LATITUDE) , "<br/>" ,
                                "Longitude: ", as.character(LONGITUDE) , "<BR/>" 
                                ),
                       clusterOptions=markerClusterOptions()) 
  })

I have an additional table with polygons that I only want to show at certain zoom levels. Basically, once close-enough in, I want to take the IDs of the points currently in view, go to the db and pull the polygons whose IDs match.

I see the flow like this: What is the current zoom level? If the zoome level is appropriate, what are the visible points? What are the IDs of the visible points? SELECT * FROM details WHERE ID in (<set of ID's of visible points>) and then render the returned polygons.

Many of the examples I see seem to assume that you have all the data you need in a single pull, and I don't want to draw that many polygons at once. I'd rather pay the toll for latency than browser memory.

====EDITED TO ADD====

The column that holds the polygon in the detail table is coded as:

    SDO_GEOMETRY(    
        2003,  -- two-dimensional polygon
        NULL,
        NULL,
        SDO_ELEM_INFO_ARRAY(1,1003,1), -- EXTERIOR POLYGON
        SDO_ORDINATE_ARRAY( 
                LONGITUDE , LATITUDE ,
                LONGITUDE + C.ROW_NUMBER*0.0001*COS(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2)), LATITUDE + C.ROW_NUMBER*0.0001*SIN(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2))  ,
                LONGITUDE + C.ROW_NUMBER*0.0001*COS(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + B.BEAMWIDTH/4 )),LATITUDE + C.ROW_NUMBER*0.0001*SIN(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + B.BEAMWIDTH/4))  ,
                LONGITUDE + C.ROW_NUMBER*0.0001*COS(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + 2*B.BEAMWIDTH/4)),LATITUDE + C.ROW_NUMBER*0.0001*SIN(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + 2*B.BEAMWIDTH/4))  ,
                LONGITUDE + C.ROW_NUMBER*0.0001*COS(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + 3*B.BEAMWIDTH/4)),LATITUDE + C.ROW_NUMBER*0.0001*SIN(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + 3*B.BEAMWIDTH/4))  ,
                LONGITUDE + C.ROW_NUMBER*0.0001*COS(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + 4*B.BEAMWIDTH/4)),LATITUDE + C.ROW_NUMBER*0.0001*SIN(0.017456329*(A.AZIMUTH - B.BEAMWIDTH/2 + 4*B.BEAMWIDTH/4))  ,
                LONGITUDE , LATITUDE
            )
    ) AS SECTORPOLYGON