Re: Slow query, possibly not using index

>
>
> =# select * from pgstatindex('media.idx_block_unused');
> version | tree_level | index_size | root_block_no | internal_pages |
> leaf_pages | empty_pages | deleted_pages | avg_leaf_density |
> leaf_fragmentation
>
> ---------+------------+------------+---------------+----------------+------------+-------------+---------------+------------------+--------------------
> 4 | 2 | 389677056 | 546 | 114 |
> 23069 | 0 | 24384 | 90.03 | 0
> (1 row)
>
> After reindex:

=# select * from pgstatindex('media.idx_block_unused');
version | tree_level | index_size | root_block_no | internal_pages |
leaf_pages | empty_pages | deleted_pages | avg_leaf_density |
leaf_fragmentation
---------+------------+------------+---------------+----------------+------------+-------------+---------------+------------------+--------------------
4 | 0 | 8192 | 0 | 0 |
0 | 0 | 0 | NaN | NaN
(1 row)

explain analyze select id from media.block b where nrefs =0 limit 1

QUERY PLAN
|
-----------------------------------------------------------------------------------------------------------------------------------------+
Limit (cost=0.14..0.46 rows=1 width=16) (actual time=0.010..0.011 rows=0
loops=1) |
-> Index Only Scan using idx_block_unused on block b (cost=0.14..698.91
rows=2231 width=16) (actual time=0.008..0.009 rows=0 loops=1)|
Heap Fetches: 0
|
Planning Time: 0.174 ms
|
Execution Time: 0.030 ms
|

It is actually empty.

Now I only need to figure out why autovacuum did not work on the index.

Thank you

Laszlo