Re: High rate of transaction failure with the Serializable Isolation Level
От | Ryan Johnson |
---|---|
Тема | Re: High rate of transaction failure with the Serializable Isolation Level |
Дата | |
Msg-id | 53D43EE7.4000500@cs.utoronto.ca обсуждение исходный текст |
Ответ на | Re: High rate of transaction failure with the Serializable Isolation Level (Reza Taheri <rtaheri@vmware.com>) |
Список | pgsql-performance |
That does sound pretty similar, modulo the raw performance difference. I have no idea how many MEE threads there were; it was just a quick run with exactly zero tuning, so I use whatever dbt5 does out of the box. Actually, though, if you have any general tuning tips for TPC-E I'd be interested to learn them (PM if that's off topic for this discussion). Regards, Ryan On 26/07/2014 7:33 PM, Reza Taheri wrote: > Hi Ryan, > Thanks a lot for sharing this. When I run with 12 CE threads and 3-5 MEE threads (how many MEE threads do you have?) @ 80-90 tps, I get something in the 20-30% of trade-result transactions rolled back depending on how I count. E.g., in a5.5-minute run with 3 MEE threads, I saw 87.5 tps. There were 29200 successful trade-result transactions. Of these, 5800were rolled back, some more than once for a total of 8450 rollbacks. So I'd say your results and ours tell similar stories! > > Thanks, > Reza > >> -----Original Message----- >> From: pgsql-performance-owner@postgresql.org [mailto:pgsql- >> performance-owner@postgresql.org] On Behalf Of Ryan Johnson >> Sent: Saturday, July 26, 2014 2:06 PM >> To: Reza Taheri >> Cc: pgsql-performance@postgresql.org >> Subject: Re: High rate of transaction failure with the Serializable Isolation >> Level >> >> Dredging through some old run logs, 12 dbt-5 clients gave the following when >> everything was run under SSI (fully serializable, even the transactions that >> allow repeatable read isolation). Not sure how that translates to your results. >> Abort rates were admittedly rather high, though perhaps lower than what >> you report. >> >> Transaction % Average: 90th % Total Rollbacks % Warning Invalid >> ----------------- ------- --------------- ------- -------------- ------- ------- >> Trade Result 5.568 0.022: 0.056 2118 417 19.69% 0 91 >> Broker Volume 5.097 0.009: 0.014 1557 0 0.00% 0 0 >> Customer Position 13.530 0.016: 0.034 4134 1 0.02% 0 0 >> Market Feed 0.547 0.033: 0.065 212 45 21.23% 0 69 >> Market Watch 18.604 0.031: 0.061 5683 0 0.00% 0 0 >> Security Detail 14.462 0.015: 0.020 4418 0 0.00% 0 0 >> Trade Lookup 8.325 0.059: 0.146 2543 0 0.00% 432 0 >> Trade Order 9.110 0.006: 0.008 3227 444 13.76% 0 0 >> Trade Status 19.795 0.030: 0.046 6047 0 0.00% 0 0 >> Trade Update 1.990 0.064: 0.145 608 0 0.00% 432 0 >> Data Maintenance N/A 0.012: 0.012 1 0 0.00% 0 0 >> ----------------- ------- --------------- ------- -------------- ------- ------- >> 28.35 trade-result transactions per second (trtps) >> >> Regards, >> Ryan >> >> On 26/07/2014 3:55 PM, Reza Taheri wrote: >>> Hi Ryan, >>> That's a very good point. We are looking at dbt5. One question: what >> throughput rate, and how many threads of execution did you use for dbt5? >> The failure rates I reported were at ~120 tps with 15 trade-result threads. >>> Thanks, >>> Reza >>> >>>> -----Original Message----- >>>> From: pgsql-performance-owner@postgresql.org [mailto:pgsql- >>>> performance-owner@postgresql.org] On Behalf Of Ryan Johnson >>>> Sent: Friday, July 25, 2014 2:36 PM >>>> To: pgsql-performance@postgresql.org >>>> Subject: Re: High rate of transaction failure with the Serializable >>>> Isolation Level >>>> >>>> On 25/07/2014 2:58 PM, Reza Taheri wrote: >>>>> Hi Craig, >>>>> >>>>>> According to the attached SQL, each frame is a separate phase in >>>>>> the >>>> operation and performs many different operations. >>>>>> There's a *lot* going on here, so identifying possible >>>>>> interdependencies isn't something I can do in a ten minute skim >>>>>> read over >>>> my morning coffee. >>>>> You didn't think I was going to bug you all with a trivial problem, >>>>> did you? :-) :-) >>>>> >>>>> Yes, I am going to have to take an axe to the code and see what pops >> out. >>>> Just to put this in perspective, the transaction flow and its >>>> statements are borrowed verbatim from the TPC-E benchmark. There >> have >>>> been dozens of TPC-E disclosures with MS SQL Server, and there are >>>> Oracle and DB2 kits that, although not used in public disclosures for >>>> various non-technical reasons, are used internally in by the DB and >>>> server companies. These 3 products, and perhaps more, were used >> extensively in the prototyping phase of TPC-E. >>>>> So, my hope is that if there is a "previously unidentified >>>>> interdependency >>>> between transactions" as you point out, it will be due to a mistake >>>> we made in coding this for PGSQL. Otherwise, we will have a hard time >>>> convincing all the council member companies that we need to change >>>> the schema or the business logic to make the kit work with PGSQL. >>>>> Just pointing out my uphill battle!! >>>> You might compare against dbt-5 [1], just to see if the same problem >>>> occurs. I didn't notice such high abort rates when I ran that >>>> workload a few weeks ago. Just make sure to use the latest commit, >>>> because the "released" version has fatal bugs. >>>> >>>> [1] >>>> >> https://urldefense.proofpoint.com/v1/url?u=https://github.com/peterge >>>> og >> hegan/dbt5&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=b9TKmA0CPjr >> oD2HLPTHU27nI9PJr8wgKO2rU9QZyZZU%3D%0A&m=6E%2F9fWJPMGjpMyP >> xtY0nsamLLW%2FNsTXu7FP9Wzauj10%3D%0A&s=b3f269216d419410f3f07bb >>>> 774a27b7d377744c9d423df52a3e62324d9279958 >>>> >>>> Ryan >>>> >>>> >>>> >>>> -- >>>> Sent via pgsql-performance mailing list >>>> (pgsql-performance@postgresql.org) >>>> To make changes to your subscription: >>>> >> https://urldefense.proofpoint.com/v1/url?u=http://www.postgresql.org/ >>>> m >>>> ailpref/pgsql- >>>> >> performance&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=b9TKmA0CP >> jroD2HLPTHU27nI9PJr8wgKO2rU9QZyZZU%3D%0A&m=6E%2F9fWJPMGjpMy >> PxtY0nsamLLW%2FNsTXu7FP9Wzauj10%3D%0A&s=45ab94ce068dbe28956af >>>> 8bb3f999e9a91138dd1e3c3345c036e87e902da1ef1 >> >> >> -- >> Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) >> To make changes to your subscription: >> https://urldefense.proofpoint.com/v1/url?u=http://www.postgresql.org/m >> ailpref/pgsql- >> performance&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=b9TKmA0CP >> jroD2HLPTHU27nI9PJr8wgKO2rU9QZyZZU%3D%0A&m=gzdXAra2QlJIiMTFSjH >> cKAsSKNR5LST%2FrsLWdeb7Y9c%3D%0A&s=673454322b6239edd9d02472e95 >> e8a6c15cb1a095d2afb9c981642e44fb40672
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