Copy from one MySQL table to another MySQL table of same database

Suppose you have mydb.mytb and you want to create mydb.mytbcopy

I have five(5) approaches to doing this copy

APPROACH #1

In the mysql client, run the following

USE mydb
CREATE TABLE mytbcopy LIKE mytb;
INSERT INTO mytbcopy SELECT * FROM mytb;

APPROACH #2

MYSQL_USER=root
MYSQL_PASS=rootpassword
MYSQL_CONN="-u${MYSQL_USER} -p${MYSQL_PASS}"
mysql ${MYSQL_CONN} -ANe"CREATE DATABASE IF NOT EXISTS test"
mysqldump ${MYSQL_CONN} mydb mytb | mysql ${MYSQL_CONN} -Dtest
mysql ${MYSQL_CONN} -ANe"ALTER TABLE test.mytb RENAME mydb.mytbcopy"

APPROACH #3

DUMPFILE=/some/path/tabledata.sql
MYSQL_USER=root
MYSQL_PASS=rootpassword
MYSQL_CONN="-u${MYSQL_USER} -p${MYSQL_PASS}"
mysql ${MYSQL_CONN} -ANe"CREATE DATABASE IF NOT EXISTS test"
mysqldump ${MYSQL_CONN} mydb mytb > ${DUMPFILE}
mysql ${MYSQL_CONN} -Dtest < ${DUMPFILE}
rm -f ${DUMPFILE}
mysql ${MYSQL_CONN} -ANe"ALTER TABLE test.mytb RENAME mydb.mytbcopy"

APPROACH #4

MYSQL_USER=root
MYSQL_PASS=rootpassword
MYSQL_CONN="-u${MYSQL_USER} -p${MYSQL_PASS}"
mysqldump ${MYSQL_CONN} mydb mytb | sed 's/mytb/mytbcopy' | mysql ${MYSQL_CONN} -Dmydb

APPROACH #5

DUMPFILE=/some/path/tabledata.sql
MYSQL_USER=root
MYSQL_PASS=rootpassword
MYSQL_CONN="-u${MYSQL_USER} -p${MYSQL_PASS}"
mysqldump ${MYSQL_CONN} mydb mytb | sed 's/mytb/mytbcopy' > ${DUMPFILE}
mysql ${MYSQL_CONN} -Dmydb < ${DUMPFILE}
rm -f ${DUMPFILE}

ANALYSIS

• APPROACH #1 is the easiest in terms of steps, but requires pushing 40 million rows into one transaction. This will be the most taxing on the InnoDB Storage Engine.
• For the other approaches, mysqldump will send 40 million row in chucks of thousands of rows
  • APPROACH #2 and APPROACH #3 will mysqldump the table into the test database. After creating the table in the test database, it is subsequently renamed and moved into the original database
  • APPROACH #4 and APPROACH #5 rename the table using sed against the stream coming from the mysqldump as it echoes the INSERT commands
  • APPROACH #2 and APPROACH #4 use pipes instead of an output file
  • APPROACH #3 and APPROACH #5 use an outpuit file for subsequent reload

If you want to copy mydb.mytb to an already existing table mydb.mytbcopy, and the two tables have identical structures:

APPROACH #6

INSERT INTO mytbcopy SELECT * FROM mytb;

Like #APPROACH 1, #APPROACH 6 would have a single transaction of 40 million rows

APPROACH #7

MYSQL_USER=root
MYSQL_PASS=rootpassword
MYSQL_CONN="-u${MYSQL_USER} -p${MYSQL_PASS}"
mysqldump ${MYSQL_CONN} -t mydb mytb | sed 's/mytb/mytbcopy' | mysql ${MYSQL_CONN} -Dmydb

This approaches does not drop the table. It simply generates the INSERTs

EPILOGUE

I cannot give you a time estimate since I do not know the make up of the DB Server, table structure, index layout, and things like these.

GIVE IT A TRY !!!