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I have to think about some of the weird multi-row insert bugs I have run into on MySQL and think that they are thread concurrency problems, but with PostgreSQL
by ehsanu1 15y ago
I have to think about some of the weird multi-row insert bugs I have run into on MySQL and think that they are thread concurrency problems, but with PostgreSQL (single threaded model) things just hum along well.
Surely that shows that there is an issue with multi-threaded programming being prone to bugs rather than parallelism in general? It seems to me like many of the people advocating parallelism as the future of software believe we have to invent better ways to manage that parallelism as well, current methods (particularly threading) being deficient. For example, see Guy Steele's work on Fortress. [1]
[1] http://www.infoq.com/presentations/Thinking-Parallel-Programming http://www.infoq.com/presentations/Thinking-Parallel-Program...
- einhverfr 15y agoOf course it is not with parallelism in general. PostgreSQL is pretty good at the process model although this means that queries can't have portions executed in parallel (within the query). Multiple sessions with multiple queries can be executed in parallel with no problem however. Note that the big open source projects (Gridsql and Postgres-XC) which get rid of this limitation currently do this through a different method without breaking single threaded process model. So the question is how intimately connected portions that run in parallel should be.