On 10/06/2014 03:21 PM, Heikki Linnakangas wrote:
On 10/06/2014 03:05 PM, Simon Riggs wrote:
My understanding of what you're saying is that if
* we have a table with >1 unique index
* and we update the values of the uniquely index columns (e.g. PK update)
* on both of the uniquely indexed column sets
then we get occaisonal deadlocks, just as we would do using current
UPDATE/INSERT.
Right. To be precise: you don't need to update both of the columns in
the same transaction, it's enough that some of the concurrent
transactions update one column, while other transactions update the
other column.
Ok, that didn't make much sense. With UPSERT, you have to specify values
for both columns. But it's sufficient that you have a mix of
transactions where only some are UPSERTs, and others are regular UPDATEs
on one of the columns.
- Heikki
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