1 Non blocking DBExport

Use this procedure to make database export without exclusive access and avoiding sessions block.

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CREATE FUNCTION export_system(load_dir VARCHAR(50) ) 
       RETURNING INTEGER, INTEGER
DEFINE rc                INTEGER;
DEFINE bad               INTEGER;
DEFINE create_ext_tab    LVARCHAR(8192);
DEFINE ins               LVARCHAR(512);
DEFINE drop_ext_tab      LVARCHAR(512);
DEFINE tname             VARCHAR(250);
DEFINE dbschema          LVARCHAR(1024);
DEFINE dbname            VARCHAR(250);
DEFINE numrows           INTEGER;

-- SET DEBUG FILE TO "/tmp/spl_debug.log";
-- TRACE ON;

LET rc=0;
LET bad=0;
LET dbname = DBINFO("dbname");
LET dbschema = "dbschema -q -d "||TRIM(dbname)||" -it DR -ss "||
                TRIM(load_dir)||"/"||TRIM(dbname)||".sql";

SYSTEM dbschema;

SET ISOLATION TO DIRTY READ;

FOREACH SELECT   TRIM(tabname) ,nrows
     INTO tname,numrows
     FROM systables
     WHERE tabid >99 AND tabtype = "T"

     LET create_ext_tab = "CREATE EXTERNAL TABLE "||tname||"_ext "||
        " SAMEAS "||tname||" USING (" ||
        "DATAFILES('DISK:"||load_dir||"/"||tname||".unl'),"||
        "FORMAT 'DELIMITED', "|| "DELIMITER '|', "||
        "RECORDEND '', "||  "DELUXE, ESCAPE, "||
        "NUMROWS "|| numrows+1||", "||    "MAXERRORS  100, "||
        "REJECTFILE '"||load_dir||"/"||tname||".reject' " ||
        " )";

     LET ins = "INSERT INTO "||tname||"_ext SELECT * FROM "||tname;
     LET drop_ext_tab = "DROP TABLE "||tname||"_ext";

     EXECUTE IMMEDIATE create_ext_tab;
     EXECUTE IMMEDIATE ins;
     EXECUTE IMMEDIATE drop_ext_tab;

     LET rc = rc + 1;

END FOREACH

RETURN rc, bad;

END FUNCTION;

2 DBImport non blocking export

If you want to restore the previous exported extructure you can do it following this procedure.

First create database where you want to import unloaded files. You can create this database in the dbspace you require. We recommend creating this database without logging and after importing change log mode manually.

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$ echo "CREATE DATABASE db_imported IN mydbspace" | dbaccess -

Exported data using the previous DBExport method, can have missing "primary-foreign" keys relationships.

You will need to deal with these problems manually. To avoid issues when loading data, it's recommended to check the sql file created by DBExport procedure and split it.

Search first foreign key creation statement in file and split sql file in two parts:

First with all statements previous to first foreign key creation.
Second with all statements after and including first foreign key creation.

You can try to automate this split method by executing this commands:

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sed -e '/(foreign/q' db_exported.sql | grep -E -v "\(foreign" > db_exported_part1.sql
sed -n `sed -n -e '/(foreign/=' db_exported.sql | head -1`',$p' db_exported.sql > db_exported_part2.sql

Where db_exported.sql is the SQL file generated by your DBExport function execution.

Execute first sql part. This will create all tables and some (not all) indexes.

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dbaccess db_imported db_exported_part1.sql

After this, create import_system function and execute it passing the unloaded data folder as a parameter. This will load all unloaded files into the database tables.

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echo 'EXECUTE FUNCTION import_system("/data/MYEXPORT")' | dbaccess db_imported

Errors thrown in this execution should be resolved manually by editing sql schema creation files and recreate database, or by editing unload file for table and removing the offending data.

After this procedure completed successfully, you can complete database creation by executing the second sql splitted file.

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dbaccess db_imported db_exported_part2.sql

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CREATE FUNCTION import_system(load_dir VARCHAR(50) ) 
       RETURNING INTEGER, INTEGER
DEFINE rc                INTEGER;
DEFINE bad               INTEGER;
DEFINE create_ext_tab    LVARCHAR(8192);
DEFINE ins               LVARCHAR(512);
DEFINE drop_ext_tab      LVARCHAR(512);
DEFINE tname             VARCHAR(250);
DEFINE dbschema          LVARCHAR(1024);
DEFINE dbname            VARCHAR(250);
DEFINE numrows           INTEGER;

-- SET DEBUG FILE TO "/tmp/spl_debug.log";
-- TRACE ON;

LET rc=0;
LET bad=0;
LET dbname = DBINFO("dbname");

-- Commented. Better do it manually
-- LET dbschema = "dbaccess "||TRIM(dbname)||" "||TRIM(load_dir)||"/"||TRIM(dbname)||".sql";
--SYSTEM dbschema;

--Do no execute transactional modes in non-transactional db
--SET ISOLATION TO DIRTY READ;

FOREACH SELECT TRIM(tabname) ,nrows
     INTO tname,numrows
     FROM systables
     WHERE tabid >99 AND tabtype = "T"

     LET create_ext_tab = "CREATE EXTERNAL TABLE "||tname||"_ext "||
        " SAMEAS "||tname||" USING (" ||
        "DATAFILES('DISK:"||load_dir||"/"||tname||".unl'),"||
        "FORMAT 'DELIMITED', "|| "DELIMITER '|', "||
        "RECORDEND '', "||  "DELUXE, ESCAPE, "||
        "NUMROWS "|| numrows+1||", "||    "MAXERRORS  100, "||
        "REJECTFILE '"||load_dir||"/"||tname||".reject' " ||
        " )";

     LET ins = "INSERT INTO "||tname||" SELECT * FROM "||tname||"_ext";
     LET drop_ext_tab = "DROP TABLE "||tname||"_ext";

     EXECUTE IMMEDIATE create_ext_tab;
     EXECUTE IMMEDIATE ins;
     EXECUTE IMMEDIATE drop_ext_tab;

     LET rc = rc + 1;

END FOREACH

RETURN rc, bad;

END FUNCTION;