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Re: [PERFORM] Partioning tsearch2 a table into chunks and accessing via views

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Benjamin Arai <me(at)benjaminarai(dot)com>
Cc: Brandon Shalton <brandon(at)cydataservices(dot)com>, PostgreSQL <pgsql-general(at)postgresql(dot)org>, pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Partioning tsearch2 a table into chunks and accessing via views
Date: 2007-08-25 18:18:33
Message-ID: 46D07279.7010603@commandprompt.com (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-performance
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Benjamin Arai wrote:
> As stated in the previous email if I use partitioning then queries will
> be executed sequentially - i.e., instead of log(n) it would be (#
> partitions) * log(n).  Right?

The planner will consider every relevant partition during the execution.
Which may be a performance hit, it may not be. It depends on many
factors. In general however, partitioning when done correctly is a
performance benefit and a maintenance benefit.

Sincerely,

Joshua D. Drake


> 
> Benjamin
> 
> On Aug 25, 2007, at 9:18 AM, Joshua D. Drake wrote:
> 
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>> Benjamin Arai wrote:
>>> This kind of disappointing, I was hoping there was more that could be
>>> done.
>>>
>>> There has to be another way to do incremental indexing without loosing
>>> that much performance.
> 
>> What makes you think you are loosing performance by using partitioning?
> 
>> Joshua D. Drake
> 
>>>
>>> Benjamin
>>>
>>> On Aug 24, 2007, at 6:29 PM, Joshua D. Drake wrote:
>>>
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>>>> Brandon Shalton wrote:
>>>>> Benjamin,
>>>>>
>>>>>
>>>>>>
>>>>>> In order to avoid the re-indexing I was thinking of instead creating
>>>>>> a new
>>>>>> table each month (building its indexes and etc) and accessing them
>>>>>> all
>>>>>> through a view. This way I only have to index the new data each
>>>>>> month.
>>>>>>
>>>>>
>>>>> Take a look at bizgres.org (based on postgres).
>>>>>
>>>>> They have a parent-child structure.
>>>>>
>>>>> The way i use it, is I have about 30M records a day that are inserted
>>>>> into the database.
>>>>>
>>>>> Each day is a "child" table to the "parent".
>>>>>
>>>>> so example:
>>>>>
>>>>> the parent table is called  "logfile"
>>>>>
>>>>> each day, is a child, with the structure like  "logfile_YYMMDD"
>>>>>
>>>>> the "child" inherits the table structure of the parent, such that you
>>>>> could query the child table name directly, or you run the query
>>>>> against
>>>>> the parent (ie. logfile table) and get all the data.
>>>>>
>>>>> the indexes are done on a per table basis, so new data that comes
>>>>> in, is
>>>>> a lesser amount, and doesn't require re-indexing.
>>>
>>>
>>>> PostgreSQL can do all of this too.
>>>
>>>> Sincerely,
>>>
>>>> Joshua D. Drake
>>>
>>>>>
>>>>>
>>>>> example:
>>>>>
>>>>> select * from logfile_070825 where datafield = 'foo'
>>>>>
>>>>> if i knew i wanted to specifically go into that child, or:
>>>>>
>>>>> select * from logfile where datafield = 'foo'
>>>>>
>>>>> and all child tables are searched and results merged.  You can perform
>>>>> any kind of sql query and field structures are you normally do.
>>>>>
>>>>> the downside is that the queries are run sequentially.
>>>>>
>>>>> so if you had 100 child tables, each table is queried via indexes,
>>>>> then
>>>>> results are merged.
>>>>>
>>>>> but, this approach does allow me to dump alot of data in, without
>>>>> having
>>>>> the re-indexing issues you are facing.
>>>>>
>>>>> at some point, you could roll up the days, in to weekly child tables,
>>>>> then monthly tables, etc.
>>>>>
>>>>> I believe Bizgres has a new version of their system that does parallel
>>>>> queries which would certainly speed things up.
>>>>>
>>>>> For your documents, you can do it by the day it was checked in, or
>>>>> maybe
>>>>> you have some other way of logically grouping, but the parent/child
>>>>> table structure really helped to solve my problem of adding in
>>>>> millions
>>>>> of records each day.
>>>>>
>>>>> The closest thing in mysql is using merge tables, which is not really
>>>>> practical when it comes time to do the joins to the tables.
>>>>>
>>>>> -brandon
>>>>>
>>>>> http://www.t3report.com - marketing intelligence for online marketing
>>>>> and affiliate programs
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ---------------------------(end of
>>>>> broadcast)---------------------------
>>>>> TIP 6: explain analyze is your friend
>>>>>
>>>
>>>
>>>> - --
>>>
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>>>>
> 
> 
>> - ---------------------------(end of
>> broadcast)---------------------------
>> TIP 6: explain analyze is your friend
> 
> 
> 
>> - --
> 
>>       === The PostgreSQL Company: Command Prompt, Inc. ===
>> Sales/Support: +1.503.667.4564   24x7/Emergency: +1.800.492.2240
>> PostgreSQL solutions since 1997  http://www.commandprompt.com/
>>             UNIQUE NOT NULL
>> Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate
>> PostgreSQL Replication: http://www.commandprompt.com/products/
> 
>> 


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PostgreSQL solutions since 1997  http://www.commandprompt.com/
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