Intervals

On Apr 26, 2005, at 18:47, Jake Stride wrote:

Is there a way to convert in interval into hours? I have a table that
records the amount of time worked by a person and want to sum up all
the
hours, however with the column being an interval once you reach more
than 24 hours it turns that into a day. This is not what I want so
instead of outputting 1day 2:00:00 I would want to output 26:00:00 is
this possible?

Search the archives from the past couple of days of the pgsql-sql
mailing list with the subject line Re: [SQL] to_char(interval) ? and
you should find a solution. The archives can be found at
http://archives.postgresql.org

Hope this helps.

Michael Glaesemann
grzm myrealbox com

On 4/26/05, Jake Stride <nsuk@users.sourceforge.net> wrote:

Is there a way to convert in interval into hours? I have a table that
records the amount of time worked by a person and want to sum up all the
hours, however with the column being an interval once you reach more
than 24 hours it turns that into a day. This is not what I want so
instead of outputting 1day 2:00:00 I would want to output 26:00:00 is
this possible?

Something along lines of select extract(epoch from '1 day 2
hours'::interval) / 3600
maybe?

Regards,
Dawid

I had the same problem and wrote a small function

create function hours(timestamp without time zone, timestamp without
time zone) RETURNS integer as
$$select cast( (cast($2 as date) - cast($1 as date)) * 24 + extract(hour
from cast($2 as time) - cast($1 as time)) as integer)$$ language SQL
IMMUTABLE;

Andrei

Jake Stride wrote:

Is there a way to convert in interval into hours? I have a table that
records the amount of time worked by a person and want to sum up all the
hours, however with the column being an interval once you reach more
than 24 hours it turns that into a day. This is not what I want so
instead of outputting 1day 2:00:00 I would want to output 26:00:00 is
this possible?

Thanks

Jake

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That is helpful, I have created a slightly different function that
returns an interval in the format HH:MM not sure if it will help anyone
or anyone has any suggestions to improve it:

create function hours(interval) returns varchar as 'SELECT
floor(extract(epoch from $1)/3600) || \':\' || (cast(extract(epoch FROM
$1) AS integer)%3600)/60;' language SQL IMMUTABLE;

Thanks

Jake

Andrei Gaspar wrote:

I had the same problem and wrote a small function

create function hours(timestamp without time zone, timestamp without
time zone) RETURNS integer as
$$select cast( (cast($2 as date) - cast($1 as date)) * 24 +
extract(hour from cast($2 as time) - cast($1 as time)) as integer)$$
language SQL IMMUTABLE;

Andrei

Jake Stride wrote:

Is there a way to convert in interval into hours? I have a table that
records the amount of time worked by a person and want to sum up all the
hours, however with the column being an interval once you reach more
than 24 hours it turns that into a day. This is not what I want so
instead of outputting 1day 2:00:00 I would want to output 26:00:00 is
this possible?

Thanks

Jake

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--
Jake Stride

Senokian Solutions Ltd
The TechnoCentre
Coventry University Technology Park
Puma Way
Coventry
CV1 2TT

T: 0870 744 2030
F: 0870 460 2623
M: 07713 627 304
E: jake.stride@senokian.com

Hi all,

I'll really appreciate any help to reduce the disk usage of
postgresql. I have a web site witch is data are refreshed each night.
Right now the disk usage is about 400 Megs but since I reload data all
nights it getting huge.

I do vacuum each time I am finished loading data.

I look into the db to found where space are used .. here is what I got
SELECT relname, (relpages*8)/1024 FROM pg_class ORDER BY relpages DESC;
relname ?column?
il_idx_1 155
il 83
vd_pk 67
il_pk 61
ic 2
ic_pk 0
iq 0

I see that index on IL (table with 4 column and ~1500000 rows) take
about 155 megs. Is that normal that IL has 83 megs but the index 155 ?

Vd_pk take about 67 megs but it the table is currently empty. Is that
means vacuum don`t shrinks indexes?

I tried a reindex with pgadminIII, here is the result. I noticed that
only system table were reindexed! Is that normal?

NOTICE: table "pg_class" was reindexed
NOTICE: table "pg_attrdef" was reindexed
NOTICE: table "pg_constraint" was reindexed
NOTICE: table "pg_description" was reindexed
NOTICE: table "pg_proc" was reindexed
NOTICE: table "pg_rewrite" was reindexed
NOTICE: table "pg_type" was reindexed
NOTICE: table "pg_attribute" was reindexed
NOTICE: table "pg_index" was reindexed
NOTICE: table "pg_operator" was reindexed
NOTICE: table "pg_opclass" was reindexed
NOTICE: table "pg_am" was reindexed
NOTICE: table "pg_amop" was reindexed
NOTICE: table "pg_amproc" was reindexed
NOTICE: table "pg_language" was reindexed
NOTICE: table "pg_aggregate" was reindexed
NOTICE: table "pg_trigger" was reindexed
NOTICE: table "pg_cast" was reindexed
NOTICE: table "pg_namespace" was reindexed
NOTICE: table "pg_conversion" was reindexed
NOTICE: table "pg_depend" was reindexed
NOTICE: table "pg_statistic" was reindexed
NOTICE: table "pg_inherits" was reindexed
NOTICE: table "pg_largeobject" was reindexed

I look at directory pg_xlog with is 164 megs. I change
checkpoint_segments to 1 in postgresql.conf to reduce this.

I have 2 questions:
-Is there any other stuff I can do to reduce disk space?
-What can I do to have � disk usage with is stable? Remember that I
flush/load data each night.

Thanks for your help
/David

Total query runtime: 141 ms.