>From the link shared above, it looks like what Meenatchi has done should work.

Do the conditions on the partial index and query match exactly? (
greater than / greater than equals mismatch maybe?)

If conditions for those partial indexes are mutually exclusive and the
query has a matching condition then Postgres can use that index alone.
Are we missing something here?


On Thu, Mar 1, 2018 at 6:33 PM, Laurenz Albe <laurenz.a...@cybertec.at> wrote:
> Meenatchi Sandanam wrote:
>> I have created a table with 301 columns(ID, 150 BIGINT, 150 TEXT). The table 
>> contains
>> multiple form data differentiated by ID range. Hence a column contains more 
>> than one form data.
>> To achieve Unique Constraint and Indexing per form, I chose PostgreSQL 
>> Partial Indexes
>> which suits my requirement. I have created Partial Indexes with ID Range as 
>> criteria and
>> it provides Uniqueness and Indexing per form basis as expected. But DML 
>> operations on a
>> particular form scans all the Indexes created for the entire table instead 
>> of scanning
>> the Indexes created for that particular form ID Range. This degrades Planner 
>> Performance
>> and Query Time more than 10 times as below,
>> Query Result for the table with 3000 Partial Indexes(15 Indexes per form) :
> It is crazy to create 3000 partial indexes on one table.
> No wonder planning and DML statements take very long, they have to consider 
> all the
> indexes.
>> explain analyse select id from form_data_copy where id between 3001 and 4000 
>> and bigint50=789;
> Use a single index on (bigint50, id) for best performance.
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com

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