RE: PostgreSQL and mySQL database size question

Bruce,

I have your book right in front of me... do you have that information in the
book?  If not, I will take a look at the FAQ.  As for mySQL, here are the
storage requirements:

Storage requirements for numeric types

Column type     Storage required
TINYINT        1 byte
SMALLINT        2 bytes
MEDIUMINT        3 bytes
INT            4 bytes
INTEGER        4 bytes
BIGINT        8 bytes
FLOAT(X)        4 if X <= 24 or 8 if 25 <= X <= 53
FLOAT            4 bytes
DOUBLE        8 bytes
DOUBLE PRECISION    8 bytes
REAL            8 bytes
DECIMAL(M,D)    M+2 bytes if D > 0, M+1 bytes if D = 0 (D+2, if M < D)
NUMERIC(M,D)    M+2 bytes if D > 0, M+1 bytes if D = 0 (D+2, if M < D)

Storage requirements for date and time types

Column type        Storage required
DATE            3 bytes
DATETIME        8 bytes
TIMESTAMP        4 bytes
TIME            3 bytes
YEAR            1 byte

Storage requirements for string types

Column type        Storage required

CHAR(M)        M bytes, 1 <= M <= 255
VARCHAR(M)        L+1 bytes, where L <= M and 1 <= M <= 255
TINYBLOB,
TINYTEXT        L+1 bytes, where L < 2^8
BLOB, TEXT        L+2 bytes, where L < 2^16
MEDIUMBLOB,
MEDIUMTEXT        L+3 bytes, where L < 2^24
LONGBLOB,
LONGTEXT        L+4 bytes, where L < 2^32
ENUM('value1','value2',...) 1 or 2 bytes, depending on the number of
enumeration values (65535 values maximum)
SET('value1','value2',...) 1, 2, 3, 4 or 8 bytes, depending on the number of
set members (64 members maximum)

Fred

-----Original Message-----
From: Bruce Momjian [mailto:pgman@candle.pha.pa.us]
Sent: Friday, April 27, 2001 1:48 PM
To: ingham@erols.com
Cc: pgsql-general@postgresql.org
Subject: Re: [GENERAL] PostgreSQL and mySQL database size question


Did you see the FAQ items on estimating database sizes?  Does MySQL have
less overhead per row?