The Perl Toolchain Summit needs more sponsors. If your company depends on Perl, please support this very important event.
 / 
PGObject-Util-BulkLoad-0.05
River stage zero No dependents
++
/ PGObject::Util::BulkLoad

NAME

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

SYNOPSIS

To insert all rows into a table using COPY: my ($dbh, @objects); PGObject::Util::BulkLoad->copy( {table => 'mytable', insert_cols => ['col1', 'col2'], dbh => $dbh}, @objects );

To copy to a temp table and then upsert: my ($dbh, @objects); 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;

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