Re: Learning EXPLAIN
Ah, I see now that the article you linked to in the OP is written by the same author and is maybe the very same content. If so, that sure seems pretty comprehensive to me, though I've also been reading this list, off and on, for many years, which has probably filled a lot of the gaps left by the original blog posts. On Fri, Dec 8, 2017 at 8:47 PM, Sam Gendler wrote: > What about the many-part explanation posted on the blog that accompanies > explain.depesz.com. Here is the first installment. I seem to remember > that there are 5 or 6 installments. > > https://www.depesz.com/2013/04/16/explaining-the-unexplainable/ > > On Fri, Dec 8, 2017 at 8:44 AM, Gustavo Velasquez > wrote: > >> Dude, >> >> You can rest assured that at least the Brazilians members will always >> know based on your last name you are not the same :-). >> >> What's the point of explaining that anyways? Got curious. >> >> As to what pertains to the topic: >> >> This is another simple yet effective doc: >> >> https://wiki.postgresql.org/images/4/45/Explaining_EXPLAIN.pdf >> >> Execution plans are tricky and reading them accurately to make good >> decisions require a lot of experience and awareness of the situation. It >> does not only require that you know how to read the tool itself but also >> know how the DB and schemas have been designed, if stats are up to date, >> how tables are populated, frequency and type of queries, adequate indexing >> in place, the hardware it sits on, etc. >> >> It's a mix of science, broaden knowledge, perspicacity, and why not >> say, it's an art. >> >> Have a great weekend. >> >> >> ___ >> Gustavo Velasquez >> +1 (256) 653-9725 <(256)%20653-9725> >> >> >> On Fri, Dec 8, 2017 at 7:32 AM, Flavio Henrique Araque Gurgel < >> fha...@gmail.com> wrote: >> >>> >>> Em sex, 8 de dez de 2017 às 14:20, Guillaume Lelarge < >>> guilla...@lelarge.info> escreveu: >>> Hi, 2017-12-08 2:12 GMT+01:00 Flávio Henrique : > Hi experts! > > I read this nice article about Understanding EXPLAIN [1] weeks ago > that opened my mind about the tool, but it seems no enough to explain a > lot > of plans that I see in this list. > Thanks. I often read responses to a plan that are not covered by the article. > > I need/want to know EXPLAIN better. > > Can you kindly advise me a good reading about advanced EXPLAIN? > > There's not much out there. This document was written after reading this list, viewing some talks (you may find a lot of them on youtube), and reading the code. I intend to update this document, since I learned quite more since 2012. Though I didn't find the time yet :-/ Anyway, thanks. >>> Hello all >>> >>> I would like to make clear that there are two "Flavio Henrique" on the >>> lists, me beeing one of them, I'd like to say that I'm not the OP. >>> A bit off-topic anyway, thanks for understanding. >>> >>> Flavio Gurgel >>> >>> >> >
Re: Learning EXPLAIN
What about the many-part explanation posted on the blog that accompanies explain.depesz.com. Here is the first installment. I seem to remember that there are 5 or 6 installments. https://www.depesz.com/2013/04/16/explaining-the-unexplainable/ On Fri, Dec 8, 2017 at 8:44 AM, Gustavo Velasquez wrote: > Dude, > > You can rest assured that at least the Brazilians members will always know > based on your last name you are not the same :-). > > What's the point of explaining that anyways? Got curious. > > As to what pertains to the topic: > > This is another simple yet effective doc: > > https://wiki.postgresql.org/images/4/45/Explaining_EXPLAIN.pdf > > Execution plans are tricky and reading them accurately to make good > decisions require a lot of experience and awareness of the situation. It > does not only require that you know how to read the tool itself but also > know how the DB and schemas have been designed, if stats are up to date, > how tables are populated, frequency and type of queries, adequate indexing > in place, the hardware it sits on, etc. > > It's a mix of science, broaden knowledge, perspicacity, and why not > say, it's an art. > > Have a great weekend. > > > ___ > Gustavo Velasquez > +1 (256) 653-9725 <(256)%20653-9725> > > > On Fri, Dec 8, 2017 at 7:32 AM, Flavio Henrique Araque Gurgel < > fha...@gmail.com> wrote: > >> >> Em sex, 8 de dez de 2017 às 14:20, Guillaume Lelarge < >> guilla...@lelarge.info> escreveu: >> >>> Hi, >>> >>> 2017-12-08 2:12 GMT+01:00 Flávio Henrique : >>> Hi experts! I read this nice article about Understanding EXPLAIN [1] weeks ago that opened my mind about the tool, but it seems no enough to explain a lot of plans that I see in this list. >>> >>> Thanks. >>> >>> I often read responses to a plan that are not covered by the article. I need/want to know EXPLAIN better. Can you kindly advise me a good reading about advanced EXPLAIN? >>> There's not much out there. This document was written after reading this >>> list, viewing some talks (you may find a lot of them on youtube), and >>> reading the code. >>> >>> I intend to update this document, since I learned quite more since 2012. >>> Though I didn't find the time yet :-/ >>> >>> Anyway, thanks. >>> >>> >> Hello all >> >> I would like to make clear that there are two "Flavio Henrique" on the >> lists, me beeing one of them, I'd like to say that I'm not the OP. >> A bit off-topic anyway, thanks for understanding. >> >> Flavio Gurgel >> >> >
Re: Learning EXPLAIN
Dude, You can rest assured that at least the Brazilians members will always know based on your last name you are not the same :-). What's the point of explaining that anyways? Got curious. As to what pertains to the topic: This is another simple yet effective doc: https://wiki.postgresql.org/images/4/45/Explaining_EXPLAIN.pdf Execution plans are tricky and reading them accurately to make good decisions require a lot of experience and awareness of the situation. It does not only require that you know how to read the tool itself but also know how the DB and schemas have been designed, if stats are up to date, how tables are populated, frequency and type of queries, adequate indexing in place, the hardware it sits on, etc. It's a mix of science, broaden knowledge, perspicacity, and why not say, it's an art. Have a great weekend. ___ Gustavo Velasquez +1 (256) 653-9725 On Fri, Dec 8, 2017 at 7:32 AM, Flavio Henrique Araque Gurgel < fha...@gmail.com> wrote: > > Em sex, 8 de dez de 2017 às 14:20, Guillaume Lelarge < > guilla...@lelarge.info> escreveu: > >> Hi, >> >> 2017-12-08 2:12 GMT+01:00 Flávio Henrique : >> >>> Hi experts! >>> >>> I read this nice article about Understanding EXPLAIN [1] weeks ago that >>> opened my mind about the tool, but it seems no enough to explain a lot of >>> plans that I see in this list. >>> >> >> Thanks. >> >> I often read responses to a plan that are not covered by the article. >>> >>> I need/want to know EXPLAIN better. >>> >>> Can you kindly advise me a good reading about advanced EXPLAIN? >>> >>> >> There's not much out there. This document was written after reading this >> list, viewing some talks (you may find a lot of them on youtube), and >> reading the code. >> >> I intend to update this document, since I learned quite more since 2012. >> Though I didn't find the time yet :-/ >> >> Anyway, thanks. >> >> > Hello all > > I would like to make clear that there are two "Flavio Henrique" on the > lists, me beeing one of them, I'd like to say that I'm not the OP. > A bit off-topic anyway, thanks for understanding. > > Flavio Gurgel > >
Re: Learning EXPLAIN
Em sex, 8 de dez de 2017 às 14:20, Guillaume Lelarge escreveu: > Hi, > > 2017-12-08 2:12 GMT+01:00 Flávio Henrique : > >> Hi experts! >> >> I read this nice article about Understanding EXPLAIN [1] weeks ago that >> opened my mind about the tool, but it seems no enough to explain a lot of >> plans that I see in this list. >> > > Thanks. > > I often read responses to a plan that are not covered by the article. >> >> I need/want to know EXPLAIN better. >> >> Can you kindly advise me a good reading about advanced EXPLAIN? >> >> > There's not much out there. This document was written after reading this > list, viewing some talks (you may find a lot of them on youtube), and > reading the code. > > I intend to update this document, since I learned quite more since 2012. > Though I didn't find the time yet :-/ > > Anyway, thanks. > > Hello all I would like to make clear that there are two "Flavio Henrique" on the lists, me beeing one of them, I'd like to say that I'm not the OP. A bit off-topic anyway, thanks for understanding. Flavio Gurgel
Re: Learning EXPLAIN
Hi, 2017-12-08 2:12 GMT+01:00 Flávio Henrique : > Hi experts! > > I read this nice article about Understanding EXPLAIN [1] weeks ago that > opened my mind about the tool, but it seems no enough to explain a lot of > plans that I see in this list. > Thanks. I often read responses to a plan that are not covered by the article. > > I need/want to know EXPLAIN better. > > Can you kindly advise me a good reading about advanced EXPLAIN? > > There's not much out there. This document was written after reading this list, viewing some talks (you may find a lot of them on youtube), and reading the code. I intend to update this document, since I learned quite more since 2012. Though I didn't find the time yet :-/ Anyway, thanks. -- Guillaume.
Learning EXPLAIN
Hi experts! I read this nice article about Understanding EXPLAIN [1] weeks ago that opened my mind about the tool, but it seems no enough to explain a lot of plans that I see in this list. I often read responses to a plan that are not covered by the article. I need/want to know EXPLAIN better. Can you kindly advise me a good reading about advanced EXPLAIN? Thank you! [1] http://www.dalibo.org/_media/understanding_explain.pdf Flávio Henrique
