Re: FTS GIN Index Question

On 09/29/2010 12:10 PM, Oleg Bartunov wrote:
> Christian,
>
> On Wed, 29 Sep 2010, Christian Ramseyer wrote:
>
>> Hi List
>>
>> I have a largish partitioned table, it has ~60 million records in each
>> of 12 partitions. It appears that a Full Text Index could speed up
>> some user queries a lot.
>>
>> A quick test with an additional tsvector column revealed that this
>> would take up around 35 GB of space for this column and then maybe 5
>> more for the gin index on it. As this is a lot of space (~ 480 GB),
>> I'm a bit tempted to use a gin index without the separate tsvector
>> column. However, the doc says that this will be slower.
>
> do you have problem with disk space ? Searching index is usually very fast
> operation, only small part of index readed. Did you checked time to read
> index ?
>

Hi Oleg, thanks for your reply,

Well I could get the disk space, but it's on a corporate SAN so it's a
bit tedious. I didn't compare directly so far since even creating both
index versions for only a single partition would bring me close to the
space limit and also take maybe 20 hours or so. So my idea was to ask
here first if I'm looking at a "a few percent" or a "orders of
magnitude" difference. But of course, if there isn't enough feeback for
an informed decision I'll either try both or just go with the
space-intensive variant to be on the safe side, user experience is
certainly more important than disk usage.

Christian