Re: pgstattuple extension for indexes

Patch applied. Thanks.

---------------------------------------------------------------------------

ITAGAKI Takahiro wrote:
> This is an extension of pgstattuple to query information from indexes.
> It supports btree, hash and gist. Gin is not supported.
> It scans only index pages and does not read corresponding heap tuples.
> Therefore, 'dead_tuple' means the number of tuples with LP_DELETE flag.
>
> Also, I added an experimental feature for btree indexes. It checks
> fragmentation factor of indexes. If an leaf has the right link on the next
> adjacent page in the file, it is assumed to be continuous (not fragmented).
> It will help us to decide when to REINDEX.
>
> Suggestions welcome.
>
> ----
> $ pgbench -i
> $ pgbench -n -t 100 -c 10
> # select * from pgstattuple('accounts_pkey');
> NOTICE: 0.36% fragmented
> HINT: continuous=273, forward=1, backward=0
> -[ RECORD 1 ]------+--------
> table_len | 2260992
> tuple_count | 100996 -- 996 tuples are dead practically,
> tuple_len | 1615936 but no LP_DELETE yet.
> tuple_percent | 71.47
> dead_tuple_count | 4
> dead_tuple_len | 64 -- 64 tuples are marked as LP_DELETE.
> dead_tuple_percent | 0
> free_space | 208188
> free_percent | 9.21
> ----
>
>
> Regards,
> ---
> ITAGAKI Takahiro
> NTT Open Source Software Center

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