Hi Hackers,
I'm trying the following TODO item:
[Indexes]
- Add fillfactor to control reserved free space during index creation
I have already made an patch and it seemed to work well.
----
$ ./pgbench -i -s 10
# select relpages from pg_class where relname = 'accounts_pkey';
relpages | 2745 ( default PCTFree is 10% )
# set btree_leaf_free_percent = 0;
# reindex index accounts_pkey;
# select relpages from pg_class where relname = 'accounts_pkey';
relpages | 2475 ( <- about 2745 * 0.9 = 2470.5 )
# set btree_leaf_free_percent = 30;
# reindex index accounts_pkey;
# select relpages from pg_class where relname = 'accounts_pkey';
relpages | 3537 ( <- about 2745 * 0.9 / 0.7 = 3529.3 )
----
And now, I need advice on some issues.
- Is it appropriate to use GUC variables to control fillfactors?
Is it better to extend CREATE INDEX / REINDEX grammar?
- Should indexes remember their fillfactors when they are created?
The last fillfactors will be used on next reindex.
- Is fillfactor useful for hash and gist indexes?
I think hash does not need it, but gist might need it.
Look forward to your comments.
Thanks,
---
ITAGAKI Takahiro
NTT Cyber Space Laboratories
btree_free_percent.patch
Description: Binary data
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