Oracle 18c; 10.7.1 EGDB; ArcGIS Desktop 10.7.1

I have a non-spatial WORKORDER table that has X & Y columns. The table has 10,000 records.

I’ve created an XY event layer from the table in ArcMap.

The performance of the XY event layer has been surprisingly good, considering the shape field is generated on-the-fly. As far as I can tell, the XY event layer refreshes in the map almost as fast as a feature class does (the difference is negligible). Whereas a spatial view on the same table performs 10-20x slower (using an SDE.ST_GEOMETRY column; generated on-the-fly).


I would like to understand more about how different layer types perform in ArcGIS.

Do XY event layers have any built-in/dynamic optimization mechanisms (like a spatial index) that would account for the surprisingly good performance?

  • 2
    Perhaps this is not a duplicate but you could at least link your previous question that is dealing with the same observation gis.stackexchange.com/questions/380120/…. BTW did the spatial index make the materialized view fast?
    – user30184
    Commented Nov 25, 2020 at 11:36
  • @user30184 Yes, the spatial index made the MV wicked-fast.
    – User1974
    Commented Nov 26, 2020 at 2:50

1 Answer 1


The XY event layer is generated on the client-side after all required library/data has been downloaded on the client machine, therefore there is no client-server connection required. It is also fast because it is generated from the Computer's RAM. In contrast, if you are querying geometry from DB, a client-server connection is required and a query is performed on the DB server which causes the latency.

  • Another thing that makes constructing geometry from the DB slow is: SDE.ST_GEOMETRY functions (such as the SDE.ST_GEOMETRY constructor) are known to be slow in general. One of the reasons might be: when it comes to SDE.ST_GEOMETRY in Oracle, ST_GEOMETRY logic is stored outside of the DB kernel in the EXTPROC.DLL. If I understand correctly, that adds some extra overhead.
    – User1974
    Commented Jun 22, 2022 at 5:51

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