How large should the temp directory be to allow Object Level Recovery to restore a large table? What should the size of the temp directory be in relation to the size of the database, size of the full backup file, size of the table and size of the backup of the table?
The size required for the temp directory in OLR is at least the uncompressed size of the table itself to be restored. There may be some additional overhead for header information and such, but it should be fairly negligible.
NOTE: These tests are limited and should not be used as a benchmark. They are simply a suggestion of possible results and should be used only as an estimation.
Testing done in Support resulted these findings:
On a database that is 8.6 GB in size, run with a LiteSpeed backup.
The compressed backup size was 4.3 GB.
In this database, one table has 2.2 million rows, which by far is the biggest in that database as all the others have a few thousand at most.
It appears to take up roughly 80% of the space for the entire database.
The OLR on the large table caused the temp file grew to a size of 6.5 GB which is around 80% of the size of the data file itself. On one of the smaller tables with 1200 rows the OLR completed so fast I could not refresh fast enough to even see the temp file before it disappeared.