Hello!
================PROPOSAL v.3===================
GOALS
======
1) Extend the current limits on database size
2) Keep non active parts of a database on slow disks (having big volume)
3) Split indices from the database
etc
SYNTAX
=======
Note: MAIN - is a name of the basic database file.
1. CREATE TABLESPACE <TS NAME> FILE '/path/to/file'
2. ALTER TABLESPACE <TS NAME> SET FILE TO '/path/to/file'
FILE can contain either an absolute path or a path relative to the
primary database file.
3. DROP TABLESPACE <TS NAME> [INCLUDING CONTENTS]
If the tablespace contains some database objects the behaviour depends
on INCLUDING CONTENTS clause. if it is specified all database objects
in the tablespace will be dropped as well. Otherwise there will be an
error.
4. CREATE TABLE ...
(
...
FIELD TYPE CONSTRAINT ... USING INDEX ... [ [IN] TABLESPACE {<TS NAME>
| PRIMARY} ] -- field constraint tablespace
...
CONSTRAINT ... USING INDEX ... [ [IN] TABLESPACE {<TS NAME> | PRIMARY}
] -- table constraint tablespace
...
)
[ [IN] TABLESPACE <TS NAME> ]
if the tablespace name is not specified PRIMARY will be used as
default tablespace for the table data.
A constraint index will use the tablespace of the table if TABLESPACE
is omitted.
5. ALTER TABLE <TABLE NAME> SET TABLESPACE [TO] {<TS NAME> | PRIMARY}
Data of the table will be moved to the specified tablespace or the
primary database.
The indices of the table without explicit TABLESPACE will be moved as
well (as if they were created now).
(And I cannot think up a good option for it)
6. CREATE INDEX … [ [IN] TABLESPACE {<TS NAME> | PRIMARY} ]
The index will be created in the specified tablespace or the primary database.
If tablespace is omitted the index will be created in the tablespace
of the table.
7. ALTER INDEX <INDEX NAME> SET TABLESPACE [TO] {<TS NAME> | PRIMARY}
Data of the index will be moved to the specified tablespace or the
primary database.
ODS CHANGES
=============
A new table RDB$TABLESPACES:
RDB$TABLESPACE_ID - SMALLINT
RDB$TABLESPACE_NAME - CHAR (63)
RDB$SECURITY_CLASS - CHAR (63)
RDB$DESCRIPTION - BLOB SUBTYPE TEXT SEGMENT SIZE 80
RDB$OWNER_NAME - CHAR (63)
RDB$FILE_NAME - VARCHAR (255)
A new field in RDB$INDICES:
RDB$TABLESPACE_NAME - CHAR (63)
A new field in RDB$RELATION_FIELDS:
RDB$TABLESPACE_NAME - CHAR (63)
New fields in RDB$RELATIONS:
RDB$TABLESPACE_NAME - CHAR (63)
RDB$POINTER_PAGE - INTEGER
RDB$ROOT_PAGE - INTEGER
Add page space id to page number in ods.h:index_root_page.
Data type of PageSpaceID changes from USHORT to ULONG.
UTILITIES
========
Logical backup
--------------------
gbak -b works as usual for now. It gets data from a database
transparently working with tablespaces.
Logical restore
--------------------
gbak -c -TABLESPACE_MAP(PING_FILE) /path/to/file/map/tablespaces
The option TABLESPACE_MAP(PING_FILE) specifies a path to the file
which maps tablespace names on file names. For example,
TS1 /path/to/tablespace1
TS2 /path/to/tablespace2
or directly in the command line
gbak -c -ts <TSNAME1>=/path/to/tablespace1 -ts <TSNAME2>=...
It allows you to restore tablespace contents to new places.
If the option is not specified gbak will use old locations for every tablespace.
The initial implementation requires explicitly specifying all
tablespace files. Later we can add merging tablespaces or default
original paths.
SOME DETAILS
=============
pag_header in every tablespace is reserved and may be replaced by a
new page type.
pag_scns and pag_pip are located in every tablespace
pag_root is located in the tablespace where a table is located
It's possible to create up to 253 tablespaces.
nbackup support is postponed.
Location of BLOB fields is postponed.
Page size is identical for every tablespace and the primary database.
Tablespaces are excluded from replication because it's physical layout
of a database and a replica may have another one.
==================END=========================
--
Roman Simakov
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