It appears to me you might be making this a lot more difficult than necessary. Why not just pre-create the required partitions daily or weekly or monthly? Or do you have a requirement that a new partition only be created the first time it is required?
On Thu, May 18, 2017 at 3:31 PM, David G. Johnston <david.g.johnston@xxxxxxxxx> wrote:
According to this post, adding "if not exists" won't really help for race conditions.
"The bottom line is that CREATE TABLE IF NOT EXISTS doesn't pretend to
handle concurrency issues any better than regular old CREATE TABLE,
which is to say not very well." - Robert Haas
It still doesn't explain how the function got past creating the table, but failed on the index. If another thread was also creating the table then there should have been lock contention on the create table statement.
AT1: Insert, failed, cannot find tableAT2: Insert, failed, cannot find tableBT2: Create Table, succeedsBT1: Create Table; fails, it exists now, if exists converts to a warningCT2: Create Index, succeedsCT1: Create Index, fails , hard errorDT2: Insert, succeedsDT1: Never HappensWhat that post seems to be describing is that it is possible the "BT1" actually hard errors instead of just being converted into a notice. There is no statement visible action to show that interleave but there is an underlying race condition since both BT1 and BT2 are executing concurrently.In short even with IF NOT EXISTS you are not guaranteed to not fail. But at least IF NOT EXISTS makes the probability of not failing > 0. It doesn't handle the concurrency any better - but it does change the outcome in some of those less-than-ideally handled situations.David J.
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Andrew W. Kerber
'If at first you dont succeed, dont take up skydiving.'
'If at first you dont succeed, dont take up skydiving.'
