I will take a look, thanks! But, upon further investigation, it appears that there is no isolation whatsoever between the initial query and the listener in ContinuousQuery. The initial query can pick up entries added after it started and which had been already sent to the local listener. This way the entry is reported twice, and hence the duplicates. This is regardless of the type of the initial query (ScanQuery or SqlQuery). This reduces the usefulness of ContinuousQuery a lot, because we have to find out a way to rule out these duplicates, which is difficult and can incur a significant overhead.
So my follow-up question is this: is it behaving as designed, or is there some mechanism to prevent these duplicates from happening? -KS From: Ilya Kasnacheev [mailto:ilya.kasnach...@gmail.com] Sent: 30 listopada 2018 14:02 To: user@ignite.apache.org Subject: Re: Continuous queries and duplicates Hello! There should be isolation in AI 2.7 as an experimental feature. Regards, -- Ilya Kasnacheev пн, 26 нояб. 2018 г. в 12:53, Sobolewski, Krzysztof <krzysztof.sobolew...@gs.com>: Thanks. This is a little disappointing. ScanQuery would probably work, but it’s not as efficient (can’t use indexes etc.). Are there any plans to enable isolation on SqlQuery? -KS From: Ilya Kasnacheev [mailto:ilya.kasnach...@gmail.com] Sent: 26 listopada 2018 08:01 To: user@ignite.apache.org Subject: Re: Continuous queries and duplicates Hello! SQL queries have no isolation currently so it is not possible to avoid the problem that you described. You could try switching to ScanQuery, see if it helps; or learning to deal with duplicates. Regards, -- Ilya Kasnacheev пт, 23 нояб. 2018 г. в 19:25, Sobolewski, Krzysztof <krzysztof.sobolew...@gs.com>: Hi, I'm wanting to use a ContinuousQuery and there is a slight issue with how it transitions from the initial query to the notifications phase. It turns out that if there are additions to the cache happening while the continuous query runs, an entry may be reported twice - once by the initial query and once by the listener. This is confirmed by experiment, BTW :) The initial query in this case is an SqlQuery. So my question is: is this intentional? Or is it a bug? Is there something I can do to mitigate this? Is this is an issue of isolation level? Thanks a lot for any pointers :) -KS ________________________________ Your Personal Data: We may collect and process information about you that may be subject to data protection laws. For more information about how we use and disclose your personal data, how we protect your information, our legal basis to use your information, your rights and who you can contact, please refer to: www.gs.com/privacy-notices<http://www.gs.com/privacy-notices> ________________________________________ Your Personal Data: We may collect and process information about you that may be subject to data protection laws. For more information about how we use and disclose your personal data, how we protect your information, our legal basis to use your information, your rights and who you can contact, please refer to: www.gs.com/privacy-notices ________________________________ Your Personal Data: We may collect and process information about you that may be subject to data protection laws. For more information about how we use and disclose your personal data, how we protect your information, our legal basis to use your information, your rights and who you can contact, please refer to: www.gs.com/privacy-notices<http://www.gs.com/privacy-notices>
