On 11/5/19 4:03 AM, Alex O'Ree wrote:
> I have a use case where by I add a bunch of rows, export then in an
> archive, then delete all the rows and repeat for weeks or months on end.
> Are there any maintenance procedures I should be running after each purge?
> Postgres and mssql has some functions to tell it to recover disk space and
> compact itself, or to notify that there was a large change in row volume.
> Is there anything like this in derby?
I would recommend using TRUNCATE TABLE to delete all the rows of the
table. This should be fast and it will re-initialize the table with an
empty backing file.
In general, you can use the SYSCS_UTIL.SYSCS_COMPRESS_TABLE system
procedure to squeeze unused space out of a table. You can use
SYSCS_UTIL.SYSCS_UPDATE_STATISTICS to regenerate the histograms which
the optimizer uses in order to calculate optimal query plans.
See the Derby Reference Manual for information on these commands.
Hope this helps,