Re: [HACKERS] [feature] cached index to speed up specific queries on extremely large data sets

2014-04-11 Thread lkcl .
On Fri, Apr 11, 2014 at 2:12 PM, Michael Paquier
 wrote:
> On Fri, Apr 11, 2014 at 9:53 PM, lkcl .  wrote:
>>> section: https://wiki.postgresql.org/wiki/Materialized_Views.
> When updating a materialized view, or refreshing it, you need as well
> to be aware that an exclusive lock is taken on it during the refresh
> in 9.3, so the materialized view cannot be accessed for read queries.

 ok.  as long as the storage of data (in the underlying table) is not
adversely affected, that would be fine.  as this is the hackers list
and this turns out to be more a user question i'll leave it for now.

>>  awesome.  uhhh, well that was easy *lol*.  once i am paid, whom do i
>> send the payment to for the fast response and incredibly valuable
>> information? :)  [this is a serious question!]
> This can be helpful:
> http://www.postgresql.org/about/donate/

 thank you michael.


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Re: [HACKERS] [feature] cached index to speed up specific queries on extremely large data sets

2014-04-11 Thread Michael Paquier
On Fri, Apr 11, 2014 at 9:53 PM, lkcl .  wrote:
> On Fri, Apr 11, 2014 at 1:26 PM, Heikki Linnakangas
>  wrote:
>> On 04/11/2014 03:20 PM, lkcl . wrote:
>>>
>>> so i had an idea.  there already exists the concept of indexes.  there
>>> already exists the concept of "cached queries".  question: would it be
>>> practical to*merge*  those two concepts such that specific queries
>>> could be*updated*  as new records are added, such that when the query
>>>
>>> is called again it answers basically pretty much immediately? let us
>>> assume that performance degradation on "update" (given that indexes
>>> already exist and are required to be updated) is acceptable.
>>
>>
>> I think you just described materialized views.
>
>  ... well... dang :)
>
>  http://tech.jonathangardner.net/wiki/PostgreSQL/Materialized_Views
>
>  ok so definitely not the snapshot materialised views, but yes!  the
> eager materialised views, definitely.
>
>> The built-in materialized
>> views in PostgreSQL are not updated immediately as the tables are modified,
>
>  ... but that would probably be enough.
>
>> but it's entirely possible to roll your own using views and triggers. There
>> are a few links on the PostgreSQL wiki, in the "Versions before 9.3"
>> section: https://wiki.postgresql.org/wiki/Materialized_Views.
When updating a materialized view, or refreshing it, you need as well
to be aware that an exclusive lock is taken on it during the refresh
in 9.3, so the materialized view cannot be accessed for read queries.

>  awesome.  uhhh, well that was easy *lol*.  once i am paid, whom do i
> send the payment to for the fast response and incredibly valuable
> information? :)  [this is a serious question!]
This can be helpful:
http://www.postgresql.org/about/donate/
-- 
Michael


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Re: [HACKERS] [feature] cached index to speed up specific queries on extremely large data sets

2014-04-11 Thread lkcl .
On Fri, Apr 11, 2014 at 1:26 PM, Heikki Linnakangas
 wrote:
> On 04/11/2014 03:20 PM, lkcl . wrote:
>>
>> so i had an idea.  there already exists the concept of indexes.  there
>> already exists the concept of "cached queries".  question: would it be
>> practical to*merge*  those two concepts such that specific queries
>> could be*updated*  as new records are added, such that when the query
>>
>> is called again it answers basically pretty much immediately? let us
>> assume that performance degradation on "update" (given that indexes
>> already exist and are required to be updated) is acceptable.
>
>
> I think you just described materialized views.

 ... well... dang :)

 http://tech.jonathangardner.net/wiki/PostgreSQL/Materialized_Views

 ok so definitely not the snapshot materialised views, but yes!  the
eager materialised views, definitely.

> The built-in materialized
> views in PostgreSQL are not updated immediately as the tables are modified,

 ... but that would probably be enough.

> but it's entirely possible to roll your own using views and triggers. There
> are a few links on the PostgreSQL wiki, in the "Versions before 9.3"
> section: https://wiki.postgresql.org/wiki/Materialized_Views.

 awesome.  uhhh, well that was easy *lol*.  once i am paid, whom do i
send the payment to for the fast response and incredibly valuable
information? :)  [this is a serious question!]

l.


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Re: [HACKERS] [feature] cached index to speed up specific queries on extremely large data sets

2014-04-11 Thread Heikki Linnakangas

On 04/11/2014 03:20 PM, lkcl . wrote:

so i had an idea.  there already exists the concept of indexes.  there
already exists the concept of "cached queries".  question: would it be
practical to*merge*  those two concepts such that specific queries
could be*updated*  as new records are added, such that when the query
is called again it answers basically pretty much immediately? let us
assume that performance degradation on "update" (given that indexes
already exist and are required to be updated) is acceptable.


I think you just described materialized views. The built-in materialized 
views in PostgreSQL are not updated immediately as the tables are 
modified, but it's entirely possible to roll your own using views and 
triggers. There are a few links on the PostgreSQL wiki, in the "Versions 
before 9.3" section: https://wiki.postgresql.org/wiki/Materialized_Views.


- Heikki


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