Hi,
> In PostgreSQL, 40001 is used for serialization failures due to MVCC
> issues, and 40P01 is used for serialization failures due to
> deadlocks. I think that many years back when PostgreSQL moved to
> MVCC it was judged important to differentiate between them with
> different SQLSTATE values
Hi,
> 40P01 is mentioned in the manual. See "A. PostgreSQL Error Codes" of
> Appendixes.
I meant "mentioned in the manual in the section about concurrency control".
Since I alluded to class 40 errors, I think it was safe to assume that I was
familiar with Appendix A...
Best,
Jon
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Hi,
The manual mentions that SERIALIZABLE transactions may abort with error 40001,
in which case the client application is supposed to retry the transaction.
I've been
stress testing an application by issuing lots of concurrent requests, and sure
enough,
every now and then I get back those 4000
Hi,
I have a problem with multiple solutions, and my question concerns which
solution is preferred given whatever optimizations happen inside the query
planner.
In a bug tracking system, I have the tables "users", "bugs" and "tags".
One bug may have one user (the reporter) but multiple tags. Mor
Hi,
> ...WHERE wid = ANY(string_to_array(?,';'))
>
> where the ? is a parameter that you replace with a semi-colon delimited
> listing of widget IDs
>
> Performance depends on specifics you have not provided, especially the
> expected number of widgets you are going to be filtering one.
Thanks
Dear postgresql-general,
What would be the best way to fetch in a single round trip a set of table rows?
To clarify, suppose I have a 'widgets' table with columns 'wid' and 'data',
and I wish to retrieve all rows that belong to the client side array $targets.
Obviously one solution would be to l
Hi,
Is it possible to do the equivalent of let-bindings in a pure SQL function?
I have a SELECT that invokes "now" multiple times. It would be nicer
to do it only once and reuse the value. Something like this:
LET right_now = SELECT now () IN
SELECT * FROM my_table WHERE right_now >= start AND
Hi,
> I don't think this is really possible with postgres PLs generally.
> Typically what you have to do is have a function that is called on an
> interval that checks for alarms and runs them.
Thanks for the prompt reply. Just to clarify: you are saying that the
function that is called with a g
Hi,
Is it possible to set an alarm within a PL/pgSQL function? By "alarm"
I mean a function which is invoked some defined time in the future,
even after the original function has terminated and returned a value
to the client.
I want an invocation of function FOO to set a "state" column of a give
Hallo,
Suppose I have the following 'scores_t' record:
create type scores_t as (item text, score int);
What's the cleanest way of converting a hstore into a set of scores_t,
with each key mapping to field 'item', and the value to field 'score'?
As an example, consider the following (non-worki
Hi,
Does Postgresql perform short-circuit boolean evaluation both in SQL
and PL/pgSQL functions? As an example, suppose I have a function called
"do_stuff" which is computationally intensive. In the example below,
will it be called for rows for which the first predicate (foobar.id = $1)
is false
Hi,
Is there support in PL/pgSQL for treating functions as first-class values?
Consider the pseudo-code simple example below, which illustrates how this
feature can be useful. I reckon that this behaviour can be emulated using
EXECUTE, but I suspect there are serious performance penalties.
Your t
Hi,
Is there any way for a SQL or PL/pgSQL function to receive a table
as parameter? As an illustration, consider the dummy example below.
Note that functions get_from_data1 and get_from_data2 follow essentially
the same pattern; it would be nice to define instead a single polymorphic
function
Hi,
> A tuple wouldn't be unusual, but you're not asking for a
> simple tuple here. What you're asking for is a value and a
> set of tuples.
Which is in itself a tuple! This discussion is again veering slightly
off-topic, but note that tuples as mathematical objects do not have such
arbitrary li
Hi,
> No, of course not. A function cannot return different
> amounts of different return-values in any language I know
> of.
Come on, you make it sound like it's something inconceivable or exotic,
even though pretty much any strongly-typed language with a post-1970s
type-system will allow a func
Hi,
> Nope, see my reply from yesterday around 20:23
> You can return a table instead, with the count added as an
> extra column.
I did see your solution, but note that it does not return a tuple
consisting of an integer and a setof (as I wanted), but instead
returns a setof of a tuple.
I still
Hi,
This thread has veered off-topic, but my original problem still remains.
Basically, I want to declare a function that returns a tuple consisting
of an integer and a set of table rows. Something like the following:
CREATE FUNCTION foobar () RETURNS (int4, SETOF users)
Now, if I understand co
Hi,
> That is certainly not going to work: that select does not produce an
> array, it produces a column of user_t (of which SELECT INTO is only
> gonna take the first, anyway).
>
> Untested, but I think you'd have better results with
>
> _page.users := array(select users from users limit 10
Hi,
I am trying to create a PL/pgSQL function whose return type is a tuple
consisting of an integer and a list of table rows. I emulate the tuple
by defining a record 'page_t' with the two fields; however, the naïve
approach of doing a SELECT INTO one the record's fields does not work
(see functi
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