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From "Rick Hillegas (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (DERBY-6136) Create a custom/optional tool for dumping the data in a corrupted database.
Date Sat, 21 Nov 2015 21:30:10 GMT

     [ https://issues.apache.org/jira/browse/DERBY-6136?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Rick Hillegas updated DERBY-6136:
---------------------------------
    Attachment: RawDBReader.java

Attaching a new version of RawDBReader.java. This version writes out a recovery script as
it creates the table functions and views needed to read the corrupt database. The recovery
script recreates all of the user schemas and tables in the new database and siphons the data
out of the corrupt tables into the new tables. The recovery script includes comments which
help an administrator identify which seg0 files correspond to which tables.

So, for instance, if the corrupt database has this schema:

{noformat}
schema1.t1
schema1.t2
schema2.t1
schema2.t2
{noformat}

...then running the following statements...

{noformat}
connect 'jdbc:derby:tmpdbs/db1;create=true';

call syscs_util.syscs_register_tool
(
  'customTool',
  true,
  'RawDBReader',
  'CONTROL11',
  'RAW11_',
  'tmpdbs/db0',
  null,
  'APP',
  null
);
{noformat}

...would create a file named recovery.sql in the current directory with the following contents...

{noformat}
connect 'jdbc:derby:tmpdbs/db1';

create schema "SCHEMA1";

-- siphon data out of c490.dat
create table "SCHEMA1"."T1" as select * from "RAW11_SCHEMA1"."T1" with no data;
insert into "SCHEMA1"."T1" select * from "RAW11_SCHEMA1"."T1";

create schema "SCHEMA2";

-- siphon data out of c4a0.dat
create table "SCHEMA1"."T2" as select * from "RAW11_SCHEMA1"."T2" with no data;
insert into "SCHEMA1"."T2" select * from "RAW11_SCHEMA1"."T2";

-- siphon data out of c4b0.dat
create table "SCHEMA2"."T1" as select * from "RAW11_SCHEMA2"."T1" with no data;
insert into "SCHEMA2"."T1" select * from "RAW11_SCHEMA2"."T1";

-- siphon data out of c4c0.dat
create table "SCHEMA2"."T2" as select * from "RAW11_SCHEMA2"."T2" with no data;
insert into "SCHEMA2"."T2" select * from "RAW11_SCHEMA2"."T2";
{noformat}


> Create a custom/optional tool for dumping the data in a corrupted database.
> ---------------------------------------------------------------------------
>
>                 Key: DERBY-6136
>                 URL: https://issues.apache.org/jira/browse/DERBY-6136
>             Project: Derby
>          Issue Type: Improvement
>          Components: Tools
>    Affects Versions: 10.11.1.1
>            Reporter: Rick Hillegas
>         Attachments: DataFileVTI.java, DataFileVTI.java, DataFileVTI.java, DataFileVTI.java,
DataFileVTI.java, DerbyRecovery-0.0.1-SNAPSHOT.jar, RawDBReader.java, RawDBReader.java, RawDBReader.java,
dataFileVTI.sql, log2[1].dat, log3[1].dat, log4[1].dat, log5[1].dat, log[1].ctrl, logmirror[1].ctrl
>
>
> It would be useful to have a tool for dumping the data in a corrupted database. This
could start out as a custom tool. After we debug the tool and get some experience with it,
we can consider promoting it to be a (possibly undocumented) optional tool which we ship with
the product. I think the tool should have the following behavior:
> 1) The tool should not subvert the security of the corrupted database. If the corrupted
database is password-protected, then you would need to present its DBO's credentials in order
to use the tool. Naturally, an encryption key would have to be presented in order to decode
an encrypted database.
> 2) The tool should not stop reading a table when it hits a corrupt record. Instead, the
tool should soldier on and collect a list of warnings on bad records.
> Such a tool would be useful in situations where some part of a heap table is corrupt
but the following heap conglomerates are intact:
> i) SYSSCHEMAS
> ii) SYSTABLES
> iii) SYSCONGLOMERATES
> iv) SYSCOLUMNS
> v) property conglomerate
> Such a tool would be useful for some situations where data can't be dumped even after
you delete the log files in order to short-circuit recovery.



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