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From "Rick Hillegas (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-5276) Reference manual has wrong length for BIGINT columns in system tables
Date Thu, 07 Jul 2011 16:27:16 GMT

    [ https://issues.apache.org/jira/browse/DERBY-5276?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13061416#comment-13061416
] 

Rick Hillegas commented on DERBY-5276:
--------------------------------------

I vote for consistency: bump all of the BIGINT lengths to 20. Certainly the SYSSEQUENCES columns
can hold negative BIGINTs. For numeric columns in the catalogs, length seems to refer to the
max number of characters needed to display the column value.

> Reference manual has wrong length for BIGINT columns in system tables
> ---------------------------------------------------------------------
>
>                 Key: DERBY-5276
>                 URL: https://issues.apache.org/jira/browse/DERBY-5276
>             Project: Derby
>          Issue Type: Bug
>          Components: Documentation
>    Affects Versions: 10.9.0.0
>            Reporter: Knut Anders Hatlen
>            Priority: Minor
>
> The description of the SYSCOLUMNS table at http://db.apache.org/derby/docs/dev/ref/rrefsistabs22441.html
says that the BIGINT columns AUTOINCREMENTVALUE, AUTOINCREMENTSTART and AUTOINCREMENTINC have
length 19. The maximum length of a BIGINT is 20 (when including the sign for negative values).
Here's an example that shows that these columns can hold values whose length is 20:
> ij> create table t(x bigint not null generated always as identity (start with -1234567890123456789,
increment by -1234567890123456789));
> 0 rows inserted/updated/deleted
> ij> select autoincrementvalue, autoincrementstart, autoincrementinc from sys.syscolumns
where columnname='X';
> AUTOINCREMENTVALUE  |AUTOINCREMENTSTART  |AUTOINCREMENTINC    
> --------------------------------------------------------------
> -1234567890123456789|-1234567890123456789|-1234567890123456789
> 1 row selected
> Other places where BIGINT columns are listed with length 19:
> SYSCONGLOMERATES - http://db.apache.org/derby/docs/dev/ref/rrefsistabs39391.html
> SYSFILES - http://db.apache.org/derby/docs/dev/ref/rrefsistabs40972.html
> SYSSEQUENCES - http://db.apache.org/derby/docs/dev/ref/rrefsistabssyssequences.html
> SYSXPLAIN_RESULTSET_TIMINGS - http://db.apache.org/derby/docs/dev/ref/rrefsysxplain_resultset_timings.html
> SYSXPLAIN_STATEMENT_TIMINGS - http://db.apache.org/derby/docs/dev/ref/rrefsysxplain_statement_timings.html
> SYSCS_DIAG.SPACE_TABLE - http://db.apache.org/derby/docs/dev/ref/rrefsyscsdiagtables.html
> I haven't verified if negative values are allowed in all of these columns. If they are
only allowed to hold non-negative values, should we keep the value 19? Or should we change
all to 20 for consistency? I'm assuming that "length" in these tables refers to the display
size of the columns.

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