From: Jinyu Zhang <beijing_pg@163.com>
To: pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Patch: Optimize memory allocation in function 'bringetbitmap'
Date: Sun, 27 Sep 2015 15:20:31 +0800 (CST)
Message-ID: <495deb78.4186.1500dacaa63.Coremail.beijing_pg@163.com> (raw)
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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
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To: pgsql-hackers@postgresql.org
Cc: beijing_pg@163.com
Subject: Re: Patch: Optimize memory allocation in function 'bringetbitmap'
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