Thanks Benchao for the feedback. For the current proposal, we recommend keeping the default value of "table.optimizer.source.predicate" as true, and setting the the default value of newly introduced option "scan.filter-push-down.enabled" to true as well.
The main purpose of doing this is to maintain consistency with previous versions, as whether to perform filter pushdown in the old version solely depends on the "table.optimizer.source.predicate" option. That means by default, as long as a TableSource implements the SupportsFilterPushDown interface, filter pushdown is allowed. And it seems that we don't have much benefit in changing the default value of "table.optimizer.source.predicate" to false. Regarding the priority of these two configurations, I believe that "table.optimizer.source.predicate" takes precedence over "scan.filter-push-down.enabled" and it exhibits the following behavior. 1. "table.optimizer.source.predicate" = "true" and "scan.filter-push-down.enabled" = "true" This is the default behavior, allowing filter pushdown for sources. 2. "table.optimizer.source.predicate" = "true" and "scan.filter-push-down.enabled" = "false" Allow the planner to perform predicate pushdown, but individual sources do not enable filter pushdown. 3. "table.optimizer.source.predicate" = "false" Predicate pushdown is not allowed for the planner. Regardless of the value of the "scan.filter-push-down.enabled" configuration, filter pushdown is disabled. In this scenario, the behavior remains consistent with the old version as well. From an implementation perspective, setting the priority of "scan.filter-push-down.enabled" higher than "table.optimizer.source.predicate" is difficult to achieve now. Because the PushFilterIntoSourceScanRuleBase at the planner level takes precedence over the source-level FilterPushDownSpec. Only when the PushFilterIntoSourceScanRuleBase is enabled, will the Source-level filter pushdown be performed. Additionally, in my opinion, there doesn't seem to be much benefit in setting a higher priority for "scan.filter-push-down.enabled". It may instead affect compatibility and increase implementation complexity. WDYT? Best, Jiabao > 2023年10月25日 11:56，Benchao Li <libenc...@apache.org> 写道： > > I agree with Jane that fine-grained configurations should have higher > priority than job level configurations. > > For current proposal, we can achieve that: > - Set "table.optimizer.source.predicate" = "true" to enable by > default, and set ""scan.filter-push-down.enabled" = "false" to disable > it per table source > - Set "table.optimizer.source.predicate" = "false" to disable by > default, and set ""scan.filter-push-down.enabled" = "true" to enable > it per table source > > Jane Chan <qingyue....@gmail.com> 于2023年10月24日周二 23:55写道： >> >>> >>> I believe that the configuration "table.optimizer.source.predicate" has a >>> higher priority at the planner level than the configuration at the source >>> level, >>> and it seems easy to implement now. >>> >> >> Correct me if I'm wrong, but I think the fine-grained configuration >> "scan.filter-push-down.enabled" should have a higher priority because the >> default value of "table.optimizer.source.predicate" is true. As a result, >> turning off filter push-down for a specific source will not take effect >> unless the default value of "table.optimizer.source.predicate" is changed >> to false, or, alternatively, let users manually set >> "table.optimizer.source.predicate" to false first and then selectively >> enable filter push-down for the desired sources, which is less intuitive. >> WDYT? >> >> Best, >> Jane >> >> On Tue, Oct 24, 2023 at 6:05 PM Jiabao Sun <jiabao....@xtransfer.cn.invalid> >> wrote: >> >>> Thanks Jane, >>> >>> I believe that the configuration "table.optimizer.source.predicate" has a >>> higher priority at the planner level than the configuration at the source >>> level, >>> and it seems easy to implement now. >>> >>> Best, >>> Jiabao >>> >>> >>>> 2023年10月24日 17:36，Jane Chan <qingyue....@gmail.com> 写道： >>>> >>>> Hi Jiabao, >>>> >>>> Thanks for driving this discussion. I have a small question that will >>>> "scan.filter-push-down.enabled" take precedence over >>>> "table.optimizer.source.predicate" when the two parameters might conflict >>>> each other? >>>> >>>> Best, >>>> Jane >>>> >>>> On Tue, Oct 24, 2023 at 5:05 PM Jiabao Sun <jiabao....@xtransfer.cn >>> .invalid> >>>> wrote: >>>> >>>>> Thanks Jark, >>>>> >>>>> If we only add configuration without adding the enableFilterPushDown >>>>> method in the SupportsFilterPushDown interface, >>>>> each connector would have to handle the same logic in the applyFilters >>>>> method to determine whether filter pushdown is needed. >>>>> This would increase complexity and violate the original behavior of the >>>>> applyFilters method. >>>>> >>>>> On the contrary, we only need to pass the configuration parameter in the >>>>> newly added enableFilterPushDown method >>>>> to decide whether to perform predicate pushdown. >>>>> >>>>> I think this approach would be clearer and simpler. >>>>> WDYT? >>>>> >>>>> Best, >>>>> Jiabao >>>>> >>>>> >>>>>> 2023年10月24日 16:58，Jark Wu <imj...@gmail.com> 写道： >>>>>> >>>>>> Hi JIabao, >>>>>> >>>>>> I think the current interface can already satisfy your requirements. >>>>>> The connector can reject all the filters by returning the input filters >>>>>> as `Result#remainingFilters`. >>>>>> >>>>>> So maybe we don't need to introduce a new method to disable >>>>>> pushdown, but just introduce an option for the specific connector. >>>>>> >>>>>> Best, >>>>>> Jark >>>>>> >>>>>> On Tue, 24 Oct 2023 at 16:38, Leonard Xu <xbjt...@gmail.com> wrote: >>>>>> >>>>>>> Thanks @Jiabao for kicking off this discussion. >>>>>>> >>>>>>> Could you add a section to explain the difference between proposed >>>>>>> connector level config `scan.filter-push-down.enabled` and existing >>>>> query >>>>>>> level config `table.optimizer.source.predicate-pushdown-enabled` ? >>>>>>> >>>>>>> Best, >>>>>>> Leonard >>>>>>> >>>>>>>> 2023年10月24日 下午4:18，Jiabao Sun <jiabao....@xtransfer.cn.INVALID> 写道： >>>>>>>> >>>>>>>> Hi Devs, >>>>>>>> >>>>>>>> I would like to start a discussion on FLIP-377: support configuration >>>>> to >>>>>>> disable filter pushdown for Table/SQL Sources[1]. >>>>>>>> >>>>>>>> Currently, Flink Table/SQL does not expose fine-grained control for >>>>>>> users to enable or disable filter pushdown. >>>>>>>> However, filter pushdown has some side effects, such as additional >>>>>>> computational pressure on external systems. >>>>>>>> Moreover, Improper queries can lead to issues such as full table >>> scans, >>>>>>> which in turn can impact the stability of external systems. >>>>>>>> >>>>>>>> Suppose we have an SQL query with two sources: Kafka and a database. >>>>>>>> The database is sensitive to pressure, and we want to configure it to >>>>>>> not perform filter pushdown to the database source. >>>>>>>> However, we still want to perform filter pushdown to the Kafka source >>>>> to >>>>>>> decrease network IO. >>>>>>>> >>>>>>>> I propose to support configuration to disable filter push down for >>>>>>> Table/SQL sources to let user decide whether to perform filter >>> pushdown. >>>>>>>> >>>>>>>> Looking forward to your feedback. >>>>>>>> >>>>>>>> [1] >>>>>>> >>>>> >>> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=276105768 >>>>>>>> >>>>>>>> Best, >>>>>>>> Jiabao >>>>>>> >>>>>>> >>>>> >>>>> >>> >>> > > > > -- > > Best, > Benchao Li
