Re: Design Question (Time Series Data)
От | Andreas Strasser |
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Тема | Re: Design Question (Time Series Data) |
Дата | |
Msg-id | fe2n6u$ang$1@news.hub.org обсуждение исходный текст |
Ответ на | Re: Design Question (Time Series Data) ("Pavel Stehule" <pavel.stehule@gmail.com>) |
Список | pgsql-general |
Pavel Stehule schrieb: > 2007/10/4, Jorge Godoy <jgodoy@gmail.com>: >> On Thursday 04 October 2007 06:20:19 Pavel Stehule wrote: >> >> I'd use the same solution that he was going to: normalized table including a >> timestamp (with TZ because of daylight saving times...), a column with a FK >> to a series table and the value itself. Index the two first columns (if >> you're searching using the value as a parameter, then index it as well) and >> this would be the basis of my design for this specific condition. >> >> Having good statistics and tuning autovacuum will also help a lot on handling >> new inserts and deletes. >> > > It's depend on work. Somewhere normalised solution can be better, > somewhere not. But I belive, if you have lot of timeseries, than > arrays is better. But I repeat, it's depend on task. > > Pavel > > ---------------------------(end of broadcast)--------------------------- > TIP 5: don't forget to increase your free space map settings > Thanks for your input so far. Maybe i should add a few things about what i will do with the data. There are only a few operations that will be done in the database: a) retrieving a slice or the whole series b) changing the frequency of the series c) grouping several series (with same time frame/frequency) together in a result set d) calculating moving averages and other econometrics stuff :-) I will always now which series i want (i.e. there will be no case where i'm searching for a value within the series). Two questions regarding the arrays: Do you know if these are really dynamic (e.g. if i have two rows, one with an array with 12 values and the other one with 1,000 values - will postgres pad the shorter row?) and is there an built-in function to retrieve arrays as rows (i know that you can build your own function for that, but i wonder whether there is a faster native function) Thank you very much! Andreas
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