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According to a comment on this question I asked about idle connections in PostgreSQL 9.2, some uncommitted transactions (possibly related to some of those idle connections) might cause some performance issues.

What is a good way to determine if there are uncommitted transactions (bonus points if there is a way to know if the connection they're on is idle or not)?

Thanks very much!

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    Have a look at pgtop. You may also hunt for rows showing "idle in transaction" in the output of ps aux. – dezso Apr 11 '13 at 5:20
  • @dezso - pgtop looks interesting; is there an equivalent for Windows? – Max Vernon♦ Apr 11 '13 at 14:25
  • @MaxVernon there are some hints that it is supposed to work on Windows but haven't seen any concrete example. But it is still a (relatively) simple Perl project, so... And anyway, it works on the pg_stat* views. – dezso Apr 11 '13 at 15:20
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If you want to see how many idle connections you have that have an open transaction, you could use:

select * 
from pg_stat_activity
where (state = 'idle in transaction')
    and xact_start is not null;

This will provide a list of open connections that are in the idle state, that also have an open transaction.

Having said that, I cannot recreate an open connection in the idle state that has an open transaction. Perhaps someone else can provide details on how to do that.

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    Beware that the state column is present only in 9.2. And for me it looks like the proper state is 'idle in transaction'. – dezso Apr 11 '13 at 16:29
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    I agree with dezso. – francs Apr 12 '13 at 2:01
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    state = 'idle' does not indicate an open transaction. – a_horse_with_no_name Dec 9 '14 at 17:23
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    I cannot recreate an open connection in the idle state that has an open transaction. Open two connections to the database, and type "begin;" in one. In the other run the above query, and you will have an idle in transaction. – X-Istence May 19 '16 at 5:19

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