Weird disk/table space consumption problem

Hi,

I had some weird disk space consumption problem. I do
(non-mission-critical) data crunching using large data sets.

For one analysis, I created a table of about 15 columns, and then ran an
insert with a subselect on the table, where the select was drawing from
three other tables, merging over ids. One of the other tables has about
60M rows.

The insert ran for about 18h before running out of disk space. Before
the query, there had been about 1TB free on the disk.

The disk itself is a soft raid 5 array under Ubuntu. (That's what I have
for large data sets...)

After the insert query failed, the disk space was not made available
again; PostgreSQL did not free it up (or would not free it up quickly).
I rebooted soon thereafter.

During boot, fsck (must have been fsck) gave me tons of freeing up inode
messages.

So, I wonder what went wrong? Any explanation? Soft raid no good for
PostgreSQL?

Thanks,
Dirk

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