Wring value of data pages average fill percent in GSTAT in case of storing
varchars that much longer than page size
-------------------------------------------------------------------------------------------------------------------
Key: CORE-4190
URL: http://tracker.firebirdsql.org/browse/CORE-4190
Project: Firebird Core
Issue Type: Bug
Components: GSTAT
Affects Versions: 3.0 Alpha 1
Reporter: Pavel Zotov
DDL:
####
create database 'txx.fdb' page_size 4096;
commit;
create table t(s varchar(32765));
commit;
insert into t values(rpad('', 32765, gen_uuid() ));
commit;
quit;
If then run gstat -r txx.fdb than we can see that:
...
Page size 4096
ODS version 12.0
...
T (128)
Primary pointer page: 198, Index root page: 199
Total formats: 1, used formats: 1
Average record length: 33037.00, total records: 1
Average version length: 0.00, total versions: 0, max versions: 0
Average fragment length: 4046.00, total fragments: 8, max fragments: 8
Average unpacked length: 32771.00, compression ratio: 0.99
Pointer pages: 1, data page slots: 1
Data pages: 1, average fill: 17%
Primary pages: 1, full pages: 0, swept pages: 0
Big record pages: 8
...
The value: "average fill: 17%" - is wrong: long string was splitted on 8 DP and
occupies in each of them almost 100% of place because of poor compressing
ratio (it was formed via gen_uuid() so RLE algorithm can not compress such
data).
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