I would rather see the "upgrade" in this case take place when the alter
happens rather than creating the non-nullable index up front with null
checks, allowing unique indexes that never have this to enjoy the
performance possible when the null checking is not necessary. This
would mean either dropping/recreating the index at alter time or adding
a new store interface to "convert" from old index type to new index
type. For simplicity I would suggest doing the drop/create in first
implementation for this path and logging a subsequent task to look at
optimizing this alter table time performance.
Anurag shekhar wrote:
Existing unique constraint will have only non nullable columns but it is
possible
to make columns null able (using statement "alter table <table name> alter
column <column name> null") .
Making columns null able isn't allowed on a column participating in
unique constraint
but as a part of this patch I have made that checking optional (only in
case of soft
upgrade it will throw an exception). Existing backing index will use the
new code
once the columns are made null able.
anurag
anurag
Mike Matrigali wrote:
Why are you upgrading the backing indexes of existing unique
constraints, those that exist should only be on non-nullable columns
so should not need to be changed. I have not read through the new
code yet, but I assume also that new constraints on non-nullable columns
also don't use the "new" code - they should not pay the left/right
search cost.
Anurag Shekhar (JIRA) wrote:
[
https://issues.apache.org/jira/browse/DERBY-3330?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Anurag Shekhar updated DERBY-3330:
----------------------------------
Attachment: derby-3330v8.diff
In this patch (derby-3330v8.diff) I have modified upgrade routine to
upgrade only the backing indexes of unique constraint. Other indexes
are left unchanged.
DataDictionaryImpl.getAllConglomerates (introduced in
derby-3330v6.dif) is no more required so I have taken it off.
Tests are running without any error or failures.
provide support for unique constraint over nullable columns
-----------------------------------------------------------
Key: DERBY-3330
URL: https://issues.apache.org/jira/browse/DERBY-3330
Project: Derby
Issue Type: New Feature
Components: Store
Affects Versions: 10.4.0.0
Environment: all
Reporter: Anurag Shekhar
Assignee: Anurag Shekhar
Attachments: BTreeController.diff, derby-3330-testcase.diff,
derby-3330.diff, derby-3330v2.diff, derby-3330v3.diff,
derby-3330v4.diff, derby-3330v5.diff, derby-3330v6.diff,
derby-3330v7.diff, derby-3330v8.diff,
FunctionalSpec_DERBY-3330-V2.html, FunctionalSpec_DERBY-3330.html,
UniqueConstraint_Implementation.html
Allow unique constraint over nullable field. Right now derby support
unique constraint only over not null columns.
