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Re: Small optimization with expanding dynamic hash table - Mailing list pgsql-hackers

From Rahila Syed
Subject Re: Small optimization with expanding dynamic hash table
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Msg-id CAH2L28vccNhRsyd1PfzdGeumKJofTh7SABA1Pmoyo_vwks=mAA@mail.gmail.com
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In response to Re: Small optimization with expanding dynamic hash table  ("cca5507" <cca5507@qq.com>)
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Hi,


Yes, for example:

low_mask: 0x011, high_mask: 0x111, old_bucket: 0x010, new_bucket: 0x110

The old_bucket's hash value like 0x***010 or 0x***110, the later is in the old_bucket is because we didn't have new_bucket before, so only hash value like 0x***110 needs relocation: hashvalue & (low_mask + 1) != 0

 
Thanks for explaining, that clarifies things for me.
It may be worthwhile to check if this change has led to any performance improvements.
  
Thank you,
Rahila syed

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