Estimating Size of Database
Is there a Web site or some info somewhere that tells you how to
estimate the size of your database.
I know what my schema is and how many records will be in each table (but
non have been inserted yet). How can I project how much disk space I
will need for the database?
Thanks!
Mitesh
In the FAQ..
http://www.postgresql.org/docs/faq-english.html#4.7
Good luck!
-Mitch
Software development :
You can have it cheap, fast or working. Choose two.
----- Original Message -----
From: "Mitesh Shah" <Mitesh.Shah@bangnetworks.com>
To: <pgsql-hackers@postgresql.org>
Sent: Thursday, April 12, 2001 6:10 PM
Subject: Estimating Size of Database
Show quoted text
Is there a Web site or some info somewhere that tells you how to
estimate the size of your database.I know what my schema is and how many records will be in each table (but
non have been inserted yet). How can I project how much disk space I
will need for the database?Thanks!
Mitesh---------------------------(end of broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?
Thanks!
One follow up question. In the example given, it says there are 36
bytes for each row header and 4 bytes for each pointer to a tuple. I'm
not sure where these numbers (36 and 4) are coming from. Are they
standard for *every* table? If my table has more than just two
integers, for example, will each row header be more than 36 bytes?
Thanks in advance.
Mitesh
-----Original Message-----
From: Mitch Vincent [mailto:mitch@venux.net]
Sent: Thursday, April 12, 2001 3:16 PM
To: Mitesh Shah; pgsql-hackers@postgresql.org
Subject: Re: Estimating Size of Database
In the FAQ..
http://www.postgresql.org/docs/faq-english.html#4.7
Good luck!
-Mitch
Software development :
You can have it cheap, fast or working. Choose two.
----- Original Message -----
From: "Mitesh Shah" <Mitesh.Shah@bangnetworks.com>
To: <pgsql-hackers@postgresql.org>
Sent: Thursday, April 12, 2001 6:10 PM
Subject: Estimating Size of Database
Is there a Web site or some info somewhere that tells you how to
estimate the size of your database.I know what my schema is and how many records will be in each table
(but
non have been inserted yet). How can I project how much disk space I
will need for the database?Thanks!
Mitesh---------------------------(end of
broadcast)---------------------------
Show quoted text
TIP 5: Have you checked our extensive FAQ?
Import Notes
Resolved by subject fallback
Mitesh Shah writes:
One follow up question. In the example given, it says there are 36
bytes for each row header and 4 bytes for each pointer to a tuple. I'm
not sure where these numbers (36 and 4) are coming from. Are they
standard for *every* table? If my table has more than just two
integers, for example, will each row header be more than 36 bytes?
More or less. Quoth the source:
typedef struct HeapTupleHeaderData
{
Oid t_oid; /* OID of this tuple -- 4 bytes */
CommandId t_cmin; /* insert CID stamp -- 4 bytes each */
CommandId t_cmax; /* delete CommandId stamp */
TransactionId t_xmin; /* insert XID stamp -- 4 bytes each */
TransactionId t_xmax; /* delete XID stamp */
ItemPointerData t_ctid; /* current TID of this or newer tuple */
int16 t_natts; /* number of attributes */
uint16 t_infomask; /* various infos */
uint8 t_hoff; /* sizeof() tuple header */
/* ^ - 31 bytes - ^ */
bits8 t_bits[MinHeapTupleBitmapSize / 8];
/* bit map of NULLs */
/* MORE DATA FOLLOWS AT END OF STRUCT */
} HeapTupleHeaderData;
Most of the fields are for maintaining information required for
transaction rollback and multi-version concurrency control, in case you
can't quite decode it. ;-)
--
Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/