Re: Indexes generated for primary key are not show
От | Andreas Pflug |
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Тема | Re: Indexes generated for primary key are not show |
Дата | |
Msg-id | 40291E63.6050704@pse-consulting.de обсуждение исходный текст |
Ответ на | Re: Indexes generated for primary key are not show (Constantin Stefanov <cstef@mail.ru>) |
Ответы |
Re: Indexes generated for primary key are not show
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Список | pgadmin-support |
Constantin Stefanov wrote: > >I do not suggest PgAdmin to become 'psql with GUI'. They are different >applications. But in some questionable issues I would suggest to use >psql as a reference, because it constains almost everything that is >needed for everyday work. >In case I explained PgAdmin does not provide enough information for >work, so I need to use another tool (psql). I am speaking only about >making PgAdmin fully sufficient for all the work which may be done >through database support. >Let me introduce 2 scenarios which explains what I mean. >Prologue is the same in both - creating table (I write SQL, but when I >stepped into the bug, I was doing the same with PgAdmin GUI). >CREATE TABLE test ( > a int, > b int, > PRIMARY KEY(a) >); >Now implicit index on column a is created, but it is not shown by PgAdmin. >I populate table with some data, use VACUUM ANALYZE to compute >statictics. Then I write query something like that >SELECT sum(b) WHERE a BETWEEN 1 AND 5; >Then 2 possible continuations. >1. I run EXPLAIN on that query, see index scan and begin to search for a >bug (I don't see index). Possible places for bug: planner (decides to >use index which is not present), PgAdmin (erraticaly parsing output), >PgAdmin (not showing index). The last is the true, but to realize it I >had to check with psql. Therefore - PgAdmin is not enough for >understanding what is happening. >2. I try to optimize query and create index with PgAdmin. Now I have 2 >almost equivalent indexes wasting space and time. If planner decides to >use index created when creating primary key, we will come to scenario 1. >If it uses manually created index, I will not see that I have >unneseccary index which consumes disk space and processor time while >inserting new rows. > >I got that it is quite a hard work to make PgAdmin show indexes from >primary key while not breaking other things. But I think it would be >nice if it falls into TODO list (as a distant entry or simply as a >suggestion). > > Well it's not really hard, just some things to think of. And the longer I think about it, and looking at your example, I'd say people analyzing a query should know a little what pgsql is doing, e.g. that unique and primary constraints include an index. Thus I tend to say we'll stay with what we got now. Regards, Andreas
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