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?
--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com