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| author | Peter Eisentraut <peter@eisentraut.org> | 2024-02-16 11:51:35 +0100 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2024-02-16 13:27:46 +0100 |
| commit | 0413a556990ba628a3de8a0b58be020fd9a14ed0 (patch) | |
| tree | 1b87efcf4ff64c49f9bd293cab80818069a658ea /doc/src | |
| parent | e85732dac0e9933cf1ec4f9df1d8ed9c221c17da (diff) | |
| download | postgresql-0413a556990ba628a3de8a0b58be020fd9a14ed0.tar.gz postgresql-0413a556990ba628a3de8a0b58be020fd9a14ed0.zip | |
Improve compression and storage support with inheritance
A child table can specify a compression or storage method different
from its parents. This was previously an error. (But this was
inconsistently enforced because for example the settings could be
changed later using ALTER TABLE.) This now also allows an explicit
override if multiple parents have different compression or storage
settings, which was previously an error that could not be overridden.
The compression and storage properties remains unchanged in a child
inheriting from parent(s) after its creation, i.e., when using ALTER
TABLE ... INHERIT. (This is not changed.)
Before this change, the error detail would mention the first pair of
conflicting parent compression or storage methods. But with this
change it waits till the child specification is considered by which
time we may have encountered many such conflicting pairs. Hence the
error detail after this change does not include the conflicting
compression/storage methods. Those can be obtained from parent
definitions if necessary. The code to maintain list of all
conflicting methods or even the first conflicting pair does not seem
worth the convenience it offers. This change is inline with what we
do with conflicting default values.
Before this commit, the specified storage method could be stored in
ColumnDef::storage (CREATE TABLE ... LIKE) or ColumnDef::storage_name
(CREATE TABLE ...). This caused the MergeChildAttribute() and
MergeInheritedAttribute() to ignore a storage method specified in the
child definition since it looked only at ColumnDef::storage. This
commit removes ColumnDef::storage and instead uses
ColumnDef::storage_name to save any storage method specification. This
is similar to how compression method specification is handled.
Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/24656cec-d6ef-4d15-8b5b-e8dfc9c833a7@eisentraut.org
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/create_table.sgml | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml index 4cbaaccaf7c..fb0e9873877 100644 --- a/doc/src/sgml/ref/create_table.sgml +++ b/doc/src/sgml/ref/create_table.sgml @@ -398,7 +398,13 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM </para> <para> - Column <literal>STORAGE</literal> settings are also copied from parent tables. + Column storage and compression settings are inherited from parent + tables. If a column is inherited from multiple tables, the storage + settings or any explicit compression settings for the column must be the + same in all parent tables, else an error is reported. Storage or + compression settings explicitly specified for the new table override any + inherited settings and can also be used to override conflicting + inherited settings. </para> <para> |