consider defaulting arraysize to 50 for oracle; at least provide an engine-level setting for it

[Mike Bayer]

this because cx_oracle performs much faster with it on. If no side effects occur for BLOBs (which I bet they do), it can be a default.

unfortunately it seems like the arraysize setting must be placed before the execute(), so we can't uniformly detect BLOBs and then set (since we dont really know until result time). this may be yet another candidate for connection-level options (but cx_oracle should really improve this).

[Mike Bayer]

this worked out well, in fact the result can have any number of BLOB/CLOB cursors opened inside of it, so the arraysize setting doesn't break it. It's when the next set of results are fetched that the previous cursors break. So in that sense if arraysize were always 50-100 here, we might not have noticed the need for BufferedColumnRow for a longer period of time. 062324bd2c2c952417edcd10a7c98a1ae7dc77c6 29e34c2a4b54053ee3a1592b40ea577f5898b749.

[Mike Bayer]

Removing milestone: 0.4.xx (automated comment)