Re: Table and Index compression
От | Pierre Frédéric Caillaud |
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Тема | Re: Table and Index compression |
Дата | |
Msg-id | op.uyag4kzicke6l8@soyouz обсуждение исходный текст |
Ответ на | Re: Table and Index compression (Greg Stark <gsstark@mit.edu>) |
Ответы |
Re: Table and Index compression
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Список | pgsql-hackers |
> Also, I'm puzzled why it would the space increase would proportional > to the amount of data and be more than 300 bytes. There's no reason it > wouldn't be a small fixed amount. The ideal is you set aside one bit > -- if the bit is set the rest is compressed and has to save at least > one bit. If the bit is not set then the rest is uncompressed. Maximum > bloat is 1-bit. In real systems it's more likely to be a byte or a > word. I'm working on cleaning the patch... I added a field in PageHeader which contains :- 0 to indicate a non-compressed page- length of compressed data if compressed If compression gains nothing (ie gains less than 4K), the page is stored raw. It seems that only pages having a PageHeader are handled by md.c, so it should work (am I mistaken ?)
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