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PGObject-Util-BulkLoad-0.06
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/ PGObject::Util::BulkLoad

NAME

PGObject::Util::BulkLoad - Bulk load records into PostgreSQL

VERSION

Version 0.06

SYNOPSIS

To insert all rows into a table using COPY:

  PGObject::Util::BulkLoad->copy(
      {table => 'mytable', insert_cols => ['col1', 'col2'], dbh => $dbh}, 
      @objects
  );

To copy to a temp table and then upsert:

  PGObject::Util::BulkLoad->upsert(
      {table       => 'mytable', 
       insert_cols => ['col1', 'col2'], 
       update_cols => ['col1'],
       key_cols    => ['col2'],
       dbh         => $dbh}, 
      @objects
  );

Or if you prefer to run the statements yourself:

  PGObject::Util::BulkLoad->statement(
     table => 'mytable', type  => 'temp', tempname => 'foo_123'
  );
  PGObject::Util::BulkLoad->statement(
     table => 'mytable', type  => 'copy', insert_cols => ['col1', 'col2']
  );
  PGObject::Util::BulkLoad->statement(
      type        => 'upsert',
      tempname    => 'foo_123',
      table       => 'mytable',
      insert_cols => ['col1', 'col2'],
      update_cols => ['col1'],
      key_cols    => ['col2']
  );

If you are running repetitive calls, you may be able to trade time for memory using Memoize by unning the following:

  PGObject::Util::BulkLoad->memoize_statements;

To unmemoize:

  PGObject::Util::BulkLoad->unmemoize;

To flush cache

  PGObject::Util::BulkLoad->flush_memoization;

As of 0.05, an object oriented interface is included. Note that the memoize calls are global but all other calls are subject to a fairly consistent interface. where the first series of arguments become the arguments (for exceptions see below) for the rest of the actions. This makes behavior management a little easier. Note that in this interface, the object is effectively immutable (or should be), so if you want to change it, create a new object:

  my $bulkloader = PGObject::Util::BulkLoad->new(
       table         => 'foo',
       tempname      => 'bar', # defaults to "pgobject_bulkload_$table"
       insert_cols   => [qw(foo bar baz baz2)],
       update_cols   => [qw(foo bar)],
       key_cols      => [qw(baz baz2)],
       dbh           => $dbh,
  );
  $bulkloader->copy(@objects);
  $bulkloader->copy_temp(@objects);
  $bulkloader->upsert(@objects);
  $bulkloader->reset_temp;
  $bulkloader->destroy_temp;

DESCRIPTION

SUBROUTINES/METHODS

memoize_statements

This function exists to memoize statement calls, i.e. generate the exact same statements on the same argument calls. This isn't too likely to be useful in most cases but it may be if you have repeated bulk loader calls in a persistent script (for example real-time importing of csv data from a frequent source).

unmemoize

Unmemoizes the statement calls.

flush_memoization

Flushes the cache for statement memoization. Does *not* flush the cache for escaping memoization since that is a bigger win and a pure function accepting simple strings.

statement

This takes the following arguments and returns a suitable SQL statement

type

Type of statement. Options are:

temp

Create a temporary table

copy

sql COPY statement

upsert

Update/Insert CTE pulling temp table

stats

Get stats on pending upsert, grouped by an arbitrary column.

table

Name of table

tempname

Name of temp table

insert_cols

Column names for insert

update_cols

Column names for update

key_cols

Names of columns in primary key.

group_stats_by

Names of columns to group stats by

upsert

Creates a temporary table named "pg_object.bulkload" and copies the data there

If the first argument is an object, then if there is a function by the name of the object, it will provide the value.

table

Table to upsert into

insert_cols

Columns to insert (by name)

update_cols

Columns to update (by name)

key_cols

Key columns (by name)

group_stats_by

This is an array of column names for optional stats retrieval and grouping. If it is set then we will grab the stats and return them. Note this has a performance penalty because it means an extra scan of the temp table and an extra join against the parent table. See get_stats for the return value information if this is set.

copy

Copies data into the specified table. The following arguments are used:

table

Table to upsert into

insert_cols

Columns to insert (by name)

get_stats

Takes the same arguments as upsert plus group_stats_by

Returns an array of hashrefs representing the number of inserts and updates that an upsert will perform. It must be performed before the upsert statement actually runs. Typically this is run via the upsert command (which automatically runs this if group_stats_by is set in the argumements hash).

There is a performance penalty here since an unindexed left join is required between the temp and the normal table.

This function requires tempname, table, and group_stats_by to be set in the argument hashref. The return value is a list of hashrefs with the following keys:

stats

Hashref with keys inserts and updates including numbers of rows.

keys

Hashref for key columns and their values, by name

AUTHOR

Chris Travers, <chris.travers at gmail.com>

CO-MAINTAINERS

Binary.com, <perl at binary.com>

BUGS

Please report any bugs or feature requests to bug-pgobject-util-bulkupload at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=PGObject-Util-BulkLoad. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc PGObject::Util::BulkLoad

You can also look for information at:

ACKNOWLEDGEMENTS

LICENSE AND COPYRIGHT

Copyright 2014 Chris Travers.

This program is distributed under the (Revised) BSD License: http://www.opensource.org/licenses/BSD-3-Clause

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

* Neither the name of Chris Travers's Organization nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.