It occurred to me the other day that synchronized scans could play havoc with clustered tables. When you dump and reload a table even if it was recently clustered if any other sequential scans are happening in the system at the time you dump it the dump could shuffle the records out of order.
Now the records would still be effectively ordered for most purposes but our statistics can't detect that. Since the correlation would be poor the restored database would have markedly different statistics showing virtually no correlation on the clustered column. Perhaps we should have some form of escape hatch for pg_dump to request real physical order when dumping clustered tables. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's 24x7 Postgres support! ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
