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Hi: I
have a job that loads a large table, but then has to “update” about
half the records for various reasons. My perception of what happens on update for
a particular recors is... - a
new record will be inserted with the updated value(s). - The
old record is marked as being obselete. - Not
sure what happens to index elements that pointed to the original (now obselete)
record. Is it updated to point directly at the newly inserted record? Or does
it use the obselete record as a “link” to the newly inserted
record? My
concern is that the resulting table is not in optimal shape for queries. I
would like to get rid of the obseleted records (vacuum I believe) but also “heal”
the table in terms of filling in the holes left where those deleted records
used to be (will gather more records per disk block read if record density on
disk is greater). Is there a way to do this? Thanks |
