Patch: Optimize memory allocation in function 'bringetbitmap'

From: "Jinyu Zhang" <beijing_pg(at)163(dot)com>
To: "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Patch: Optimize memory allocation in function 'bringetbitmap'
Date: 2015-09-27 07:20:31
Message-ID: 495deb78.4186.1500dacaa63.Coremail.beijing_pg@163.com
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BRIN Scan: Optimize memory allocation in function 'bringetbitmap'.
We can allocate memory for some pointer before do long loop instead of allocating
memory in long loop.

Before optimizing code (warm run)
postgres=# select count(*) from lineitem where l_orderkey=1;
count
-------
6
(1 row)

Time: 456.219 ms

After optimizing code (warm run)
postgres=# select count(*) from lineitem where l_orderkey=1;
count
-------
6
(1 row)

Time: 349.219 ms

The following shows the DDL of this test case.
CREATE TABLE LINEITEM ( L_ORDERKEY INTEGER NOT NULL,
L_PARTKEY INTEGER NOT NULL,
L_SUPPKEY INTEGER NOT NULL,
L_LINENUMBER INTEGER NOT NULL,
L_QUANTITY DECIMAL(15,2) NOT NULL,
L_EXTENDEDPRICE DECIMAL(15,2) NOT NULL,
L_DISCOUNT DECIMAL(15,2) NOT NULL,
L_TAX DECIMAL(15,2) NOT NULL,
L_RETURNFLAG CHAR(1) NOT NULL,
L_LINESTATUS CHAR(1) NOT NULL,
L_SHIPDATE DATE NOT NULL,
L_COMMITDATE DATE NOT NULL,
L_RECEIPTDATE DATE NOT NULL,
L_SHIPINSTRUCT CHAR(25) NOT NULL,
L_SHIPMODE CHAR(10) NOT NULL,
L_COMMENT VARCHAR(44) NOT NULL);

copy lineitem from '/home/jinyu/mywork/dbgen/lineitem.tbl' delimiter '|';
create index brinLineitem on lineitem using brin(L_ORDERKEY) with(pages_per_range = 1);

Jinyu Zhang

网易考拉iPhone6s玫瑰金5288元,现货不加价

Attachment Content-Type Size
patch_optimize_mem application/octet-stream 5.0 KB

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