>We do not delete everything at one (in this case the truncate woudl resolve the problem).
Please, it is very important you provide PostgreSQL version & O/S, as improvements to VACUUM may play a role here.
Is there any reason you cannot partition the table? Moving the data to separate partitions (based on a date or key field) will allow you to vacuum full only 1 partition at a time.
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Melvin Davidson I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.