Re: [PATCHES] HOT + MVCC-safe cluster conflict fix

[Bruce Momjian]

Your patch has been added to the PostgreSQL unapplied patches list at:

http://momjian.postgresql.org/cgi-bin/pgpatches

It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.

---


Heikki Linnakangas wrote:
> Hi Pavan,
> 
> Here's a little patch against CVS HEAD + NewHOT-v7.0.patch to fix the 
> conflict between MVCC-safe cluster and HOT.
> 
> index_getnext is modified to return all tuples in a HOT chain when 
> called with SnapshotAny. Cluster will insert them all as normal cold 
> updates.
> 
> -- 
>Heikki Linnakangas
>EnterpriseDB   http://www.enterprisedb.com


> 
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-- 
  Bruce Momjian  <[EMAIL PROTECTED]>  http://momjian.us
  EnterpriseDB   http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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Re: [PATCHES] HOT + MVCC-safe cluster conflict fix

[Pavan Deolasee]

On 4/19/07, Heikki Linnakangas <[EMAIL PROTECTED]> wrote:


Hi Pavan,

Here's a little patch against CVS HEAD + NewHOT-v7.0.patch to fix the
conflict between MVCC-safe cluster and HOT.

index_getnext is modified to return all tuples in a HOT chain when
called with SnapshotAny. Cluster will insert them all as normal cold
updates.



Thanks Heikki. We might need to tweak it a bit because I think I had
made an assumption that heap_hot_fetch() should be called only on
the root tuple. Anyways, would look at it.

Thanks

--
Pavan Deolasee
EnterpriseDB http://www.enterprisedb.com

[PATCHES] HOT + MVCC-safe cluster conflict fix

[Heikki Linnakangas]

Hi Pavan,

Here's a little patch against CVS HEAD + NewHOT-v7.0.patch to fix the 
conflict between MVCC-safe cluster and HOT.


index_getnext is modified to return all tuples in a HOT chain when 
called with SnapshotAny. Cluster will insert them all as normal cold 
updates.


--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com
Index: src/backend/access/index/indexam.c
===
RCS file: /home/hlinnaka/pgcvsrepository2/pgsql/src/backend/access/index/indexam.c,v
retrieving revision 1.97
diff -c -r1.97 indexam.c
*** src/backend/access/index/indexam.c	5 Jan 2007 22:19:23 -	1.97
--- src/backend/access/index/indexam.c	19 Apr 2007 12:07:35 -
***
*** 404,409 
--- 404,428 
  
  	SCAN_CHECKS;
  	GET_SCAN_PROCEDURE(amgettuple);
+ 	
+ 	/*
+ 	 * With SnapshotAny, there can be multiple visible tuples in a HOT chain,
+ 	 * all represented by a single index entry. We need to return all of them
+ 	 * to the caller. The first one is returned in the loop below as usual,
+ 	 * but before we move to the next index tuple, return any remaining tuples
+ 	 * from the previous chain.
+ 	 */
+ 	if (BufferIsValid(scan->xs_cbuf) && scan->xs_snapshot == SnapshotAny)
+ 	{
+ 		bool found;
+ 
+ 		LockBuffer(scan->xs_cbuf, BUFFER_LOCK_SHARE);
+ 		found = heap_hot_fetch(scan->heapRelation, scan->xs_snapshot,
+ 			   heapTuple, scan->xs_cbuf);
+ 		LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
+ 		if (found)
+ 			return heapTuple;
+ 	}
  
  	/* just make sure this is false... */
  	scan->kill_prior_tuple = false;
Index: src/backend/commands/cluster.c
===
RCS file: /home/hlinnaka/pgcvsrepository2/pgsql/src/backend/commands/cluster.c,v
retrieving revision 1.159
diff -c -r1.159 cluster.c
*** src/backend/commands/cluster.c	8 Apr 2007 01:26:28 -	1.159
--- src/backend/commands/cluster.c	19 Apr 2007 12:02:00 -
***
*** 717,722 
--- 717,723 
  		 scan->xs_cbuf))
  		{
  			case HEAPTUPLE_DEAD:
+ 			case HEAPTUPLE_DEAD_CHAIN:
  /* Definitely dead */
  isdead = true;
  break;

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