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Re: [HACKERS] GSoC 2017: weekly progress reports (week 8) - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: [HACKERS] GSoC 2017: weekly progress reports (week 8)
Date
Msg-id CAPpHfdv9F_gKvXMj7WvAgjX0UrNmY8N5BvhVPpqBTc01QECBsw@mail.gmail.com
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In response to Re: [HACKERS] GSoC 2017: weekly progress reports (week 8)  (Shubham Barai <shubhambaraiss@gmail.com>)
Responses Re: [HACKERS] GSoC 2017: weekly progress reports (week 8)
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Hi!

On Fri, Jul 28, 2017 at 7:58 AM, Shubham Barai <shubhambaraiss@gmail.com> wrote:
I am attaching a patch for predicate locking in SP-Gist index

I took a look over this patch.

newLeafBuffer = SpGistGetBuffer(index,
 GBUF_LEAF | (isNulls ? GBUF_NULLS : 0),
 Min(totalLeafSizes,
 SPGIST_PAGE_CAPACITY),
 &xlrec.initDest);
 PredicateLockPageSplit(index,
 BufferGetBlockNumber(current->buffer),
 BufferGetBlockNumber(newLeafBuffer));

You move predicate lock during split only when new leaf page is allocated.  However SP-GiST may move items to the free space of another busy page during split (see other branches in doPickSplit()).  Your patch doesn't seem to handle this case correctly.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company 

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