Re: Why my query not using index to sort? - Mailing list pgsql-general
| From | Adrian Klaver |
|---|---|
| Subject | Re: Why my query not using index to sort? |
| Date | |
| Msg-id | 50c0d333-b979-c34b-46bd-a686b429868f@aklaver.com Whole thread Raw |
| In response to | Re: Why my query not using index to sort? (Arup Rakshit <ar@zeit.io>) |
| Responses |
Re: Why my query not using index to sort?
|
| List | pgsql-general |
On 9/30/18 1:21 PM, Arup Rakshit wrote: > Hi Adrian, > > I am on psql (10.5, server 9.5.14). > > I am still investigating the Rails side. I found a blog > (https://schneems.com/2015/10/27/sql-in-rails-logs.html) , where a Rails > core team member said that Load time is basically SQL execution time. From what I read he said it is the SQL call, with no indication of whether that includes the the ORM/framwork overhead to make the call or not. > > I also had done a little test on psql. Here I also see the explain > output and actual execution time far apart and it matches what I see in > the Rails log. No it does not. In a previous post you said: "It takes now between 1.7 to 1.9 ms in production." Which was confirmed by the information here: https://gist.github.com/aruprakshit/a6bd7ca221c9a13cd583e0827aa24ad6 Below you show 5.046 ms and then 14.377 ms. The second number is not really relevant as it includes the time to write out to a file, so is different operation all together. > > docking_dev=# explain analyze select > > "vessels" > .* > > from > > > "vessels" > > > where > > > "vessels"."deleted_at" is null > > > and "vessels"."company_id" in > ('6f56abfe-a355-44b9-b728-a642f661a8e7', > > 'c82d08d7-bec1-4413-b627-63e1898c568c', > > > '5404cd95-29d9-44c3-8ca3-261be373bf31', > > > '19d5224a-ff2b-43c4-b756-4e82c29a4712', > > > '6fed40b7-fdd7-4efb-a163-c2b42e6486ae', > > > 'a0793a69-330c-4a6b-8a55-ee6daf574371', > > > '3e936613-04e6-4db0-8595-5b8ae9cc2a40', > > > '059275e2-933d-4543-8eef-91a5af87849b', > > > 'c64a658a-6ff1-4e76-8551-dfa62383bac3', > > > 'ce634593-555a-4f3c-af79-d7a7cf3796fb', > > > 'e18c4dab-f536-46f8-9f85-8bf51dbe989e', > > > 'cfe6a534-b33b-4493-862e-6aa4f0b4a790', > > > '58d628c1-af0d-4e64-b672-87c77b677c7b', > > > '36cb8ab0-5e8a-40db-a296-5e4b5dc666f3', > > > '0d15288d-c042-461e-b4cb-0b2ad47ead29', > > > 'e8cd498d-9da5-4d54-ac07-e4fc48c84a67', > > > 'c192c117-0ec7-4c1d-94a6-0a773e70e58b', > > > '97dd15db-5862-4d49-9047-e3e0307e5c95', > > > '03766e4f-4f64-4927-be6d-a126958ac1a8', > > > '26987b95-8652-491c-b950-4fb3128f4714', > > > 'c4f55044-3f4e-439e-a586-8b6978c7b406', > > > '36825da8-2f58-4a62-bdb4-2b91cbe18299', > > > 'cca256cf-b415-472c-8b9f-a8432d02c580'); > > > > > > > QUERY PLAN > ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- > Seq Scan on vessels (cost=0.00..630.62 rows=923 width=1439) (actual > time=0.279..4.921 rows=753 loops=1) > Filter: ((deleted_at IS NULL) AND (company_id = ANY > ('{6f56abfe-a355-44b9-b728-a642f661a8e7,c82d08d7-bec1-4413-b627-63e1898c568c,5404cd95-29d9-44c3-8ca3-261be373bf31,19d5224a-ff2b-43c4-b756-4e82c29a4712,6fed40b7-fdd7-4efb-a163-c2b42e6486ae,a0793a69-330c-4a6b-8a55-ee6daf574371,3e936613-04e6-4db0-8595-5b8ae9cc2a40,059275e2-933d-4543-8eef-91a5af87849b,c64a658a-6ff1-4e76-8551-dfa62383bac3,ce634593-555a-4f3c-af79-d7a7cf3796fb,e18c4dab-f536-46f8-9f85-8bf51dbe989e,cfe6a534-b33b-4493-862e-6aa4f0b4a790,58d628c1-af0d-4e64-b672-87c77b677c7b,36cb8ab0-5e8a-40db-a296-5e4b5dc666f3,0d15288d-c042-461e-b4cb-0b2ad47ead29,e8cd498d-9da5-4d54-ac07-e4fc48c84a67,c192c117-0ec7-4c1d-94a6-0a773e70e58b,97dd15db-5862-4d49-9047-e3e0307e5c95,03766e4f-4f64-4927-be6d-a126958ac1a8,26987b95-8652-491c-b950-4fb3128f4714,c4f55044-3f4e-439e-a586-8b6978c7b406,36825da8-2f58-4a62-bdb4-2b91cbe18299,cca256cf-b415-472c-8b9f-a8432d02c580}'::uuid[]))) > Rows Removed by Filter: 1947 > Planning time: 2.249 ms > Execution time: 5.046 ms > (5 rows) > > docking_dev=# \timing on > Timing is on. > docking_dev=# \o ~/Downloads/a.txt > > > docking_dev=# select > > "vessels" > .* > > from > > > "vessels" > > > where > > > "vessels"."deleted_at" is null > > > and "vessels"."company_id" in > ('6f56abfe-a355-44b9-b728-a642f661a8e7', > > 'c82d08d7-bec1-4413-b627-63e1898c568c', > > > '5404cd95-29d9-44c3-8ca3-261be373bf31', > > > '19d5224a-ff2b-43c4-b756-4e82c29a4712', > > > '6fed40b7-fdd7-4efb-a163-c2b42e6486ae', > > > 'a0793a69-330c-4a6b-8a55-ee6daf574371', > > > '3e936613-04e6-4db0-8595-5b8ae9cc2a40', > > > '059275e2-933d-4543-8eef-91a5af87849b', > > > 'c64a658a-6ff1-4e76-8551-dfa62383bac3', > > > 'ce634593-555a-4f3c-af79-d7a7cf3796fb', > > > 'e18c4dab-f536-46f8-9f85-8bf51dbe989e', > > > 'cfe6a534-b33b-4493-862e-6aa4f0b4a790', > > > '58d628c1-af0d-4e64-b672-87c77b677c7b', > > > '36cb8ab0-5e8a-40db-a296-5e4b5dc666f3', > > > '0d15288d-c042-461e-b4cb-0b2ad47ead29', > > > 'e8cd498d-9da5-4d54-ac07-e4fc48c84a67', > > > 'c192c117-0ec7-4c1d-94a6-0a773e70e58b', > > > '97dd15db-5862-4d49-9047-e3e0307e5c95', > > > '03766e4f-4f64-4927-be6d-a126958ac1a8', > > > '26987b95-8652-491c-b950-4fb3128f4714', > > > 'c4f55044-3f4e-439e-a586-8b6978c7b406', > > > '36825da8-2f58-4a62-bdb4-2b91cbe18299', > > > 'cca256cf-b415-472c-8b9f-a8432d02c580'); > Time: 14.377 ms > docking_dev=# > > > Thanks, > > Arup Rakshit > ar@zeit.io <mailto:ar@zeit.io> > > > >> On 29-Sep-2018, at 2:50 AM, Adrian Klaver <adrian.klaver@aklaver.com >> <mailto:adrian.klaver@aklaver.com>> wrote: >> >> On 9/28/18 12:14 PM, Arup Rakshit wrote: >>> Forgot to mention in my previous email, it was a quick send click. >>> Sorry for that. >>> In the gist you need to see all the line with Vessel Load(.. . I load >>> the page multiple times to catch the different times, so you will the >>> line multiple times there in the log file. >> >> Do you know what Vessel Load () is actually measuring? >> >> To me it looks like it is covering both the query(including ROR >> overhead) and the HTTP request/response cycle. >> >> Also have you looked at: >> >> https://guides.rubyonrails.org/debugging_rails_applications.html#impact-of-logs-on-performance >> >>> Thanks, >>> Arup Rakshit >>> ar@zeit.io <mailto:ar@zeit.io> >> >> >> -- >> Adrian Klaver >> adrian.klaver@aklaver.com > -- Adrian Klaver adrian.klaver@aklaver.com
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