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This patch makes some improvements to the rtree index implementation:

Browse Source 
(1) Keep a pin on the scan's current buffer and mark buffer. This
avoids the need to do a ReadBuffer() for each tuple produced by the
scan. Since ReadBuffer() is expensive, this is a significant win.

(2) Convert a ReleaseBuffer(); ReadBuffer() pair into
ReleaseAndReadBuffer(). Surely not a huge win, but it saves a lock
acquire/release...

(3) Remove a bunch of duplicated code in rtget.c; make rtnext() handle
both the "initial result" and "subsequent result" cases.

(4) Add support for index tuple killing

(5) Remove rtscancache(): it is dead code, for the same reason that
gistscancache() is dead code (an index scan ought not be invoked with
NoMovementScanDirection).

The end result is about a 10% improvement in rtree index scan perf,
according to contrib/rtree_gist/bench.
This commit is contained in:
Neil Conway
2005-01-18 23:25:55 +00:00
parent 1f5299bc3f
commit b4297c177c
4 changed files with 159 additions and 156 deletions
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17
src/include/access/rtree.h
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/rtree.h,v 1.36 2004/12/31 22:03:21 pgsql Exp $
* $PostgreSQL: pgsql/src/include/access/rtree.h,v 1.37 2005/01/18 23:25:55 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@@ -59,11 +59,14 @@ typedef struct RTSTACK
/*
* When we're doing a scan, we need to keep track of the parent stack
* for the marked and current items. Also, rtrees have the following
* property: if you're looking for the box (1,1,2,2), on the internal
* nodes you have to search for all boxes that *contain* (1,1,2,2), and
* not the ones that match it. We have a private scan key for internal
* nodes in the opaque structure for rtrees for this reason. See
* access/index-rtree/rtscan.c and rtstrat.c for how it gets initialized.
* property: if you're looking for the box (1,1,2,2), on the internal
* nodes you have to search for all boxes that *contain* (1,1,2,2),
* and not the ones that match it. We have a private scan key for
* internal nodes in the opaque structure for rtrees for this reason.
* See access/index-rtree/rtscan.c and rtstrat.c for how it gets
* initialized. We also keep pins on the scan's current buffer and
* marked buffer, if any: this avoids the need to invoke ReadBuffer()
* for each tuple produced by the index scan.
*/
typedef struct RTreeScanOpaqueData
@@ -73,6 +76,8 @@ typedef struct RTreeScanOpaqueData
uint16 s_flags;
int s_internalNKey;
ScanKey s_internalKey;
Buffer curbuf;
Buffer markbuf;
} RTreeScanOpaqueData;
typedef RTreeScanOpaqueData *RTreeScanOpaque;