pgloader/pgloader.1.txt

= pgloader(1) =

== NAME ==

pgloader - Import CSV data and Large Object to PostgreSQL

== SYNOPSIS ==

pgloader [--version] [-c configuration file]
         [-p pedantic] [-d debug] [-v verbose] [-q quiet] [-s summary]
	 [-l loglevel] [-L logfile]
         [-n dryrun] [-Cn count] [-Fn from] [-In from id]
         [-E input files encoding] [-R reformat:path]
         [Section1 Section2]

== DESCRIPTION ==

+pgloader+ imports data from a flat file and insert it into a database
table. It uses a flat file per database table, and you can configure
as many Sections as you want, each one associating a table name and a
data file.

Data are parsed and rewritten, then given to PostgreSQL +COPY+
command. Parsing is necessary for dealing with end of lines and
eventual trailing separator characters, and for column reordering:
your flat data file may not have the same column order as the database
table has.

+pgloader+ is also able to load some large objects data into
PostgreSQL, as of now only Informix +UNLOAD+ data files are
supported. This command gives large objects data location information
into the main data file. +pgloader+ parse it add the +text+ or +bytea+
content properly escaped to the +COPY+ data.

+pgloader+ issue some timing statistics every +commit_every+ commits
(see Configuration for this setting). At the end of each section
processing, a summary of overall operations, numbers of rows copied
and commits, time it took in seconds, errors logged and database
errors is issued.

+pgloader+ is available from +pgfoundry+ at
http://pgfoundry.org/projects/pgloader/[], where you'll find a debian
package, a source package and an anonymous CVS.

== OPTIONS ==

In order for pgloader to run, you have to edit a configuration file
(see Configuration) consisting of Section definitions. Each section
refers to a PostgreSQL table into which some data is to be loaded.

--version::

    print out pgloader version, then quit.

-c, --config::

    specifies the configuration file to use. The default file name is
    pgloader.conf, searched into current working directory.

-p, --pedantic::

    activates the pedantic mode, where any warning is considered as a fatal
    error, thus stopping the processing of the input file.

-d, --debug::

    makes pgloader say it all about what it does. debug implies verbose.

-v, --verbose::

    makes pgloader very verbose about what it does.

-q, --quiet::

    makes pgloader very quiet about what it does: only output errors.

-l, --loglevel::

    log level to use when reporting to the console, see +client_min_messages+.

-L, --logfile::

    file where to log messages, see +log_min_messages+.

-s, --summary::

    makes pgloader print a 'nice' summary at the end of operations.

-n, --dry-run::

    makes pgloader simulate operations, that implies no database connection and
    no data extraction from blob files.

-D, --disable-triggers::

    makes +pgloader+ issue a +ALTER TABLE <table> DISABLE TRIGGER ALL+
    before loading the data, and +ENABLE+ them again once data is
    loaded.

-T, --truncate::

    makes +pgloader+ issue a +TRUNCATE <table>+ SQL command before
    importing data.

-V, --vacuum::

    makes +pgloader+ issue a +VACUUM ANALYZE <table>+ SQL command
    after data loading.

-C, --count::

    Number of input lines to process, default is to process all the input
    lines.

-F, --from::
+
Input line number from which we begin to process (and count). pgloader
will skip all preceding lines.
+
You can't use both -F and -I at the same time.

-I, --from-id::
+
From which id do we begin to process (and count) input lines.
+
When a composite key is used, you have to give each column of the key
separated by comma, on the form col_name=value.
+
Please notice using the --from-id option implies pgloader will try to
get row id of each row, it being on the interval processed or
not. This could have some performance impact, and you may end up
prefering to use --from instead.
+
  Example: pgloader -I col1:val1,col2:val2
+
You can't use both -F and -I at the same time.

-E, --encoding::

    Input data files encoding. Defaults to 'latin9'.

-R, --reformat_path::

    PATH where to find reformat python modules, defaults to
    +/usr/share/pgloader/reformat+. See +reformat_path+ option for
    syntax and default value.

Section::
+
is the name of a configured Section describing some data to load
+
Section arguments are optionnal, if no section is given all configured
sections are processed.

== GLOBAL CONFIGURATION SECTION ==

The configuration file has a .ini file syntax, its first section has
to be the pgsql one, defining how to access to the PostgreSQL database
server where to load data. Then you may define any number of sections,
each one describing a data loading task to be performed by pgloader.

The [pgsql] section has the following options, which all must be set.

host::

    PostgreSQL database server name, for example localhost.

port::

    PostgreSQL database server listening port, 5432. You have to fill this
    entry.

base::

    The name of the database you want to load data into.

user::

    Connecting PostgreSQL user name.

pass::

    The password of the user. The better is to grant a trust access privilege
    in PostgreSQL pg_hba.conf. Then you can set this entry to whatever value
    you want to.

client_encoding::
+
Set this parameter to have pgloader connects to PostgreSQL using this
encoding.
+
This parameter is optionnal and defaults to 'latin9'.

datestyle::
+
Set this parameter to have pgloader connects to PostgreSQL using this
datestyle setting.
+
This parameter is optionnal and has no default value, thus pgloader will
use whatever your PostgreSQL is configured to as default.

copy_every::
+
When issuing +COPY+ PostgreSQL commands, pgloader will not make a
single big +COPY+ attempt, but copy copy_every lines at a time.
+
This parameter is optionnal and defaults to 10000.

//////////////////////////////////////////
commit_every::
+
PostgreSQL +COMMIT+ frequency, exprimed in +UPDATE+ orders. A good
value is 1000, that means commiting the SQL transaction every 1000
input lines.
+
+pgloader+ issues commit every +commit_every+ updates, on connection
closing and when a SQL error occurs.
+
This parameter is optionnal and defaults to 1000.
//////////////////////////////////////////

copy_delimiter::
+
The field separator to use in +COPY FROM+ produced statements. If you
don't specify this, the same separator as the one given in +field_sep+
parameter will be used.
+
Please note PostgreSQL requires a single char properly encoded (see
your +client_encoding+ parameter), or it abort in error and even may
crash.
+
This parameter is optionnal and defaults to +field_sep+.

newline_escapes::
+
For parameter effect description, see below (same name, table local
setting).
+
You can setup here a global escape caracter, to be considered on each
and every column of each and every text-format table defined
thereafter.

null::
+
You can configure here how null value is represented into your flat
data file.
+
This parameter is optionnal and defaults to +''+ (that is +empty string+).

empty_string::
+
You can configure here how empty values are represented into your flat
data file.
+
This parameter is optionnal and defaults to +$$'\ '$$+ (that is
backslash followed by space).

reformat_path::
+
When using +reformat+ option, provide here a colon separated path list
where to look for reformating module.
+
    reformat_path = .:/home/dim/PostgreSQL/pgfoundry/pgloader/reformat
+
The directories given here should exist and contain a
+$$__init__.py$$+ file (for python to consider them as packages), the
only modules and functions used in the package will be the one you
configure with +reformat+ section specific option.
+
Default value is +/usr/share/pgloader/reformat+, which is where the
provided +debian+ package of +pgloader+ installs the +reformat+
modules.
+
If the +-R+ or +--reformat_path+ command line option is used, it will
have precedence over configuration file setting.

client_min_messages::

    Minimum level of messages to print to the console while
    running. Defined levels are +DEBUG+, +INFO+, +WARNING+, +ERROR+,
    +CRITICAL+, from min to max.  +

log_min_messages::

    Minimum level of messages to print out to the log file, which
    defaults to +/tmp/pgloader.log+. See +client_min_messages+ for
    available levels.

log_file::

    Relative or absolute path to the +log_file+ where to log messages
    of level of at least +log_min_messages+ level. The 'dirname' of
    the given +log_file+, if it doesn't exists, will be created by
    +pgloader+. If any error prevents +pgloader+ to use the
    +log_file+, it will default to using +/tmp/pgloader.log+ and say
    so.

lc_messages::

    The PostgreSQL session will use this +LC_MESSAGES+ setting if
    given, defaults to server configuration by not issuing anything
    with respect to this setting when not set.

== COMMON FORMAT CONFIGURATION PARAMETERS ==

You then can define any number of data section, and give them an
arbitrary name. Some options are required, some are actually optional,
in which case it is said so thereafter.

First, we'll go through common parameters, applicable whichever format
of data you're referring to. Then text-format only parameters will be
presented, followed by csv-only parameters.

template::
+
When this option is set, current section is to be considered a
template, that is only read from section(s) using it as so (see
+use_template+ below).
+
The value given to the option is not taken into account by +pgloader+,
only the fact that it exists has meaning. But +ConfigParser+ requires
a value to be affected to consider the option set. Use +True+ as a
value, for example.

use_template::
+
This option setting have to be the name of a template section, which
can define the exact same options as a normal section. If the actual
section and the +use_template+ template section both define the same
option, the former is used: actual setting overrides template's one.

table::

    The table name of the database where to load data.

format::
+
The format data are to be found, either text or csv.
+
See next sections for format specific options.

filename::

    The absolute path to the input data file. The large object files
    are to be found into the same directory. Their name can be in the
    form +[bc]lob[0-9a-f]{4}.[0-9a-f]{3}+, but this information is not
    used by +pgloader+.

input_encoding::

    The encoding of the configured +filename+.

reject_log::

    In case of errors processing input data, a human readable log per rejected
    input data line is produced into the +reject_log+ file.

reject_data::

    In case of errors processing input data, the rejected input line is
    appended to the +reject_data+ file.

field_sep::
+
The field separator used into the data file. The same separator will
be used by the generated +COPY+ commands, thus +pgloader+ does not
have to deal with escaping the delimiter it uses (input data has to
have escaped it).
+
This parameter is optionnal and defaults to pipe char +$$'|'$$+.

client_encoding::
+
Set this parameter to have pgloader connects to PostgreSQL using this
encoding.
+
This parameter is optionnal and defaults to 'latin9'. If defined on a
table level, this local value will overwritte the global one.

datestyle::
+
Set this parameter to have pgloader connects to PostgreSQL using this
+datestyle+ setting.
+
This parameter is optionnal and has no default. If defined on a table
level, this local value will overwritte the global one.

null::
+
You can configure here how null value is represented into your flat
data file.
+
This parameter is optionnal and defaults to +''+ (that is empty
string). If defined on a table level, this local value will overwritte
the global one.

empty_string::
+
You can configure here how empty values are represented into your flat
data file.
+
This parameter is optionnal and defaults to '\ ' (that is backslash
followed by space). If defined on a table level, this local value will
overwritte the global one.

//////////////////////////////////////////
index::
+
Table index definition, to be used in blob +UPDATE+'ing. You define an
index column by giving its name and its column number (as found into
your data file, and counting from 1) separated by a colon. If your
table has a composite key, then you can define multiple columns here,
separated by a comma.
+
    index = colname:3, other_colname:5
//////////////////////////////////////////

columns::
+
You can define here table columns, by giving their names and
optionnaly column number (as found into your data file, and counting
from 1) separated by a colon.
+
    columns = x, y, a, b, d:6, c:5
+
Note you'll have to define here all the columns to be found in data
file, whether you want to use them all or not. When not using them
all, use the +only_cols+ parameter to restrict.
+
As of +pgloader 2.2+ the column list used might not be the same as the
table columns definition.
+
As of +pgloader 2.2.1+ you can omit column numbering if you want to, a
counter is then maintained for you, starting from 1 and set to +$$last
value + 1$$+ on each column, where +last value+ was either computed or
given in the config. So you can even omit only 'some' columns in
there.
+
In case you have a lot a columns per table, you will want to use
multiple lines for this parameter value. Python ConfigParser module
knows how to read multi-line parameters, you don't have to escape
anything.
+
An easy way to get the list of attributes (columns) of your tables
(say +a+, +b+ and +c+) is by the following query:
+
    BEGIN;
    CREATE AGGREGATE array_acc(anyelement) (
        SFUNC = array_append,
        STYPE = anyarray,
        INITCOND = '{}'
    );
    
    SELECT relname, array_acc(attname)
      FROM pg_attribute a join pg_class c on a.attrelid = c.oid
     WHERE relname in ('a', 'b', 'c')
           and attname not in ('tableoid','cmax','xmax','cmin','xmin','ctid')
  GROUP BY relname;
    
    ROLLBACK;
+

user_defined_columns::
+
Those are special columns not found in the data file but which you
want to load into the database. The configuration options beginning
with +udc_+ are taken as column names with constant values. The
following example define the column +c+ as having the value +constant
value+ for each and every row of the input data file.
+
    udc_c = constant value
+
The option +copy_columns+ is used to define the exact +columnsList+
given to +COPY+.
+
A simple use case is the loading into the same database table of data
coming from more than one file. If you need to keep track of the data
origin, add a column to the table model and define a 'udc_' for
+pgloader+ to add a constant value in the database.
+
Using user-defined columns require defining +copy_columns+ and is not
compatible with +only_cols+ usage.
+

copy_columns::
+
This options defines the columns to load from the input data file and
the user defined columns, and in which order to do this. Place here
the column names separated by commas.
+
    copy_columns = b, c, d
+
This option is required if any user column is defined, and conflicts
with the +only_cols+ option. It won't have any effect when used in a
section where no user column is defined.

only_cols::
+
If you want to only load a part of the columns you have into the data
file, this option let you define which columns you're interrested
in. +only_col+ is a comma separated list of ranges or values, as in
following example.
+
    only_cols = 1-3, 5
+
This parameter is optionnal and defaults to the list of all columns
given on the columns parameter list, in the colname order.
+
This option conflicts with user defined columns and +copy_columns+
option.

blob_columns::
+
The definition of the colums where to find some blob or clob
reference. This definition is composed by a table column name, a
column number (couting from one) reference into the Informix +UNLOAD+
data file, and a large object type, separated by a colon. You can have
several columns in this field, separated by a comma.
+
Supported large objects type are Informix blob and clob, the awaited
configuration string are respectively +ifx_blob+ for binary (bytea)
content type and +ifx_clob+ for text type values.
+
Here's an example:
+
    blob_type = clob_column:3:ifx_blob, other_clob_column:5:ifx_clob

reformat::
+
Use this option when you need to preprocess some column data with
+pgloader+ reformating modules, or your own. The value of this option is
a comma separated list of columns to rewrite, which are a colon
separated list of column name, reformat module name, reformat function
name. Here's an example to reformat column +dt_cx+ with the
+mysql.timestamp()+ reformating function:
+
    reformat = dt_cx:mysql:timestamp
+
See global setting option +reformat_path+ for configuring where
+pgloader+ will look for reformat packages and modules.
+
If you want to write a new formating function, provide a python
package called +reformat+ (a directory of this name containing an
empty +$$ __init__.py$$+ file will do) and place in there arbitrary named
modules (+foo.py+ files) containing functions with the following
signature:
+
    def bar(reject, input)
+
The reject object has a +log(self, messages, data = None)+ method for
you to log errors into +section.rej.log+ and +section.rej+ files.



== TEXT FORMAT CONFIGURATION PARAMETERS ==

field_count::
+
The +UNLOAD+ command does not escape newlines when they appear into
table data. Hence, you may obtain multi-line data files, where a
single database row (say tuple if you prefer to) can span multiple
physical lines into the unloaded file.
+
If this is your case, you may want to configure here the number of
columns per tuple. Then pgloader will count columns and buffer line
input in order to re-assemble several physical lines into one data row
when needed.
+
This parameter is optionnal.

trailing_sep::
+
If this option is set to True, the input data file is known to append
a +field_sep+ as the last character of each of its lines. With this
option set, this last character is then not considered as a field
separator.
+
This parameter is optionnal and defaults to +False+.

newline_escapes::
+
Sometimes the input data file has field values containing newlines,
and the export program used (as Informix +UNLOAD+ command) escape
in-field newlines.  So you want +pgloader+ to keep those newlines,
while at the same time preserving them.
+
This option does the described work on specified fields and
considering the escaping character you configure, following this
syntax:
+
    newline_escapes = colname:\, other_colname:§
+
This parameter is optionnal, and the extra work is only done when
set. You can configure +newline_escapes+ for as many fields as
necessary, and you may configure a different escaping character each
time.
+
Please note that at the moment, +pgloader+ does only support one
character length +newline_escapes+.
+
When both a global (see +[pgsql]+ section) +newline_escapes+ parameter
and a table local one are set, +pgloader+ issues a warning and only
consider the global setting.

== CSV FORMAT CONFIGURATION PARAMETERS ==

doublequote::

    Controls how instances of +quotechar+ appearing inside a field
    should be themselves be quoted. When +True+, the character is
    doubled. When +False+, the +escapechar+ is used as a prefix to the
    +quotechar+. It defaults to +True+.

escapechar::

    A one-character string used by the writer to escape the delimiter
    if quoting is set to +QUOTE_NONE+ and the +quotechar+ if
    +doublequote+ is +False+. On reading, the +escapechar+ removes any
    special meaning from the following character. It defaults to
    +None+, which disables escaping.

quotechar::

    A one-character string used to quote fields containing special
    characters, such as the +delimiter+ or +quotechar+, or which
    contain new-line characters.  It defaults to '"'.

skipinitialspace::

    When +True+, whitespace immediately following the +delimiter+ is
    ignored. The default is +False+.

== CONFIGURATION EXAMPLE ==

Please see the given configuration example which should be distributed in
+/usr/share/doc/pgloader/examples/pgloader.conf+.

The example configuration file comes with example data and can be used
a unit test of +pgloader+.

== HISTORY ==

+pgloader+ has first been a +tcl+ tool written by Jan Wieck and
released by Christopher Kings-Lynne, who created the
http://pgfoundry.org[pgfoundry] project for it to be published. Later
on, Jean-Paul Argudo took over the maintenance.  When it became clear
that it would be easier to rewrite it in another language than to
properly learn +tcl+ and develop some missing options, +pgloader+ was
rewritten in python by Dimitri Fontaine.

+pgloader+ was rewritten to act as an Informix to PostgreSQL migration
helper which imported Informix large objects directly into a
PostgreSQL database.

Then as we got some data we couldn't file tools to care about, we
decided +ifx_blob+ would become +pgloader+, as it had to be able to
import all Informix +UNLOAD+ data. Those data contains escaped
separator into unquoted data field and multi-lines fields (+\r+ and
+\n+ are not escaped).

+pgloader+ has since gained some more features allowing it to directly
import +mysqldump -T+ data, and is known to be used in production
environments where a +PostgreSQL+ database is used for reporting
against data from several servers running different RDBMS softwares.

== BUGS ==

Please report bugs to Dimitri Fontaine <dim@tapoueh.org>.

When last line is alone on a +COPY+ command and its parsing ends in
error (not enough columns read for example), no information is given
back by +pgloader+.

== AUTHORS ==

+pgloader+ is written by Dimitri Fontaine <dim@tapoueh.org>.