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Manual Reference Pages  -  PGLOADER (1)


pgloader - Import CSV data and Large Object to PostgreSQL



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]


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, where you'll find a debian package, a source package and an anonymous CVS.


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.


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.

-1, --psycopg1

Force usage of psycopg version 1.

-2, --psycopg2

Force usage of psycopg version 2.


Force pgloader to use given version of psycopg, either 1 or 2.


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.


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.


PostgreSQL database server name, for example localhost.


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


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


Connecting PostgreSQL user name.


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.


Set this parameter to have pgloader connects to PostgreSQL using this encoding.

This parameter is optionnal and defaults to latin9.


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.


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.


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.


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.


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).


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).


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 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.


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


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


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.


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.


Number of sections to load at the same time, each in its own thread. Default to 1, which is the legacy behaviour and the more common wanted one.


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.


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.


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.


The table name of the database where to load data.


The format data are to be found, either text or csv.

See next sections for format specific options.


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 used by pgloader.


The encoding of the configured filename.


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


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


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 '|'.


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.


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.


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.


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.


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:

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;


As of pgloader 2.3.0 you can simply set columns = * and pgloader will issue the needed SQL for you. This only works if your data file and your table definition both present the columns in the exact same order, obviously.

Internally, pgloader will issue a COPY statement without the column names if possible, meaning when only_cols is not used at the same time as columns = * is used.


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.


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.


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.


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


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 file will do) and place in there arbitrary named modules ( 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.


This section is about loading a single given section by multiple threads. To load several sections at once in a parallel fashion, please refer to max_parallel_sections global option.


This option allows to configure how many threads pgloader will use to process current section. See split_file_reading for more information about how those threads will serve the loading. Defaults to 1, which is the legacy behaviour and the more needed one too.


This option is only used by pgloader when section_threads is more than 1, and configures how the work will be spread to threads. It defaults to False.

When split_file_reading is True, pgloader will have each section thread process a part of the input file. The file splitting is done at the byte level, not at the line count level: knowing how many lines the input file has would require loading it first...

When split_file_reading is False, pgloader will have one thread read the input file and give workers threads input lines to process in a round-robin fashion. Please note the reader thread will have to parse the lines (according to format parameter).


When split_file_reading is False, this is the size of the pgloader queue used to balance input lines to workers threads. Instead of giving them one line at a time in a round-robin fashion, pgloader will feed workers rrqueue_size lines at a time. This defaults to copy_every.



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.


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.


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.



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.


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.


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 ".


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


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.


pgloader has first been a tcl tool written by Jan Wieck and released by Christopher Kings-Lynne, who created the pgfoundry[1] 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.


Please report bugs to Dimitri Fontaine <>, and see current list of known bugs in the BUGS.txt distributed file (debian package includes it at /usr/share/doc/pgloader/BUGS.txt or online at following url:


pgloader is written by Dimitri Fontaine <>.


1. pgfoundry
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PGLOADER (1) 03/10/2008

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