How does Index scan perform a scan for overlapping Index Cond ?
If I get a plan like this, what will actually be performed if EXPLAIN
shows this:
Sort (cost=12.90..12.91 rows=1 width=207)
Sort Key: log_actionseq
-> Index Scan using sl_log_1_idx2_hu, sl_log_1_idx2_hu,
sl_log_1_idx2_hu, sl_log_1_idx2_hu on sl_log_1 (cost=0.00..12.89 rows=1
width=207)
Index Cond: (
((log_xid < '1349053093') AND (log_xid >= '1349052761'))
OR ((log_xid < '1349053093') AND (log_xid >= '1349052761'))
OR ((log_xid < '1349053093') AND (log_xid >= '1349052761'))
OR ((log_xid < '1349053093') AND (log_xid >= '1349052761'))
)
(this is from a query generated by Slony for 4 sets replicated from the
same master)
Will the same range be scanned 4 times ?
Or is the scan method smart enough to collapse them into one pass ?
Or does this actually mean 4 conactenated index scans (Index Scan using
X, X, X, X on sl_log_1) ?
--
Hannu Krosing <[EMAIL PROTECTED]>
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