Re: README of hash index

On Fri, Sep 16, 2016 at 04:50:53PM +0530, Amit Kapila wrote:
> Currently README of hash module contain algorithms written in below form.
> 
> The insertion algorithm is rather similar:
> 
> pin meta page and take buffer content lock in shared mode
> loop:
> compute bucket number for target hash key
> release meta page buffer content lock
> if (correct bucket page is already locked)
> break
> release any existing bucket page lock (if a concurrent split happened)
> take heavyweight bucket lock in shared mode
> retake meta page buffer content lock in shared mode
> -- (so far same as reader)
> release pin on metapage
> ..
> ..
> 
> I have mostly updated them in the patches I have proposed to improve
> hash index.  However, each time I try to update them, I find that it
> is easy to follow the code than to read and understand the existing
> algorithm written in above form from README.
> 
> Do others find it useful to maintain the algorithms in above form?
> 

Hi Amit,

Speaking for myself, I think it does help to have a text description
of the algorithm to use as a guide while trying to understand the code.
For beginners (me), it is not always obvious what a section of code is
doing.

Regards,
Ken