OpenText Analytics Database 26.2.x – COPY

Sql-Reference: Parameters

Mon, 01 Jan 0001 00:00:00 +0000

COPY parameters and their descriptions are divided into the following sections:

Target options

The following options apply to the target tables and their columns:

LABEL: Assigns a label to a statement to identify it for profiling and debugging.

{ database | namespace }

Name of the database or namespace that contains table:

Database name: If specified, it must be the current database.
Namespace name (Eon Mode only): You must specify the namespace of objects in non-default namespaces. If no namespace is provided, it is assumed the object is in the default namespace.

schema

Name of the schema, by default public. If you specify the namespace or database name, you must provide the schema name, even if the schema is public.

If you specify a schema name that contains a period, the part before the period cannot be the same as the name of an existing namespace.

Note

COPY ignores schema when used in CREATE EXTERNAL TABLE or CREATE FLEX EXTERNAL TABLE statements.

target-table

The target columnar or flexible table for loading new data. OpenText™ Analytics Database loads the data into all projections that include columns from the schema table.

column-as-expression

An expression used to compute values for the target column, which must not be of a complex type. For example:

=> COPY t(year AS TO_CHAR(k, 'YYYY')) FROM 'myfile.dat'

Use this option to transform data when it is loaded into the target database.

For details, see Transforming data during loads.

column

Restricts the load to one or more specified columns in the table. If you omit specifying columns, COPY loads all columns by default.

Table columns that you omit from the column list are assigned their DEFAULT or SET USING values, if any; otherwise, COPY inserts NULL.

If you leave the column parameter blank to load all columns in the table, you can use the optional parameter COLUMN OPTION to specify parsing options for specific columns.

The data file must contain the same number of columns as the COPY command's column list.

COLUMN OPTION

Specifies load metadata for one or more columns declared in the table column list. For example, you can specify that a column has its own DELIMITER, ENCLOSED BY, or NULL AS expression, and so on. You do not have to specify every column name explicitly in the COLUMN OPTION list, but each column you specify must correspond to a column in the table column list.

Column options

Depending on how they are specified, the following COPY options can qualify specific columns or all columns. Some parser-specific options can also apply to either specific columns or all columns. See Global and column-specific options For details about these two modes.

ENFORCELENGTH

If specified, COPY rejects data rows of type CHAR, VARCHAR, BINARY, and VARBINARY, or elements of those types in collections, if they are larger than the declared size.

By default, COPY truncates offending rows of these data types and elements of these types in collections, but does not reject the rows. For more details, see Handling Messy Data.

If a collection does not fit with all of its elements, COPY rejects the row without truncating. It does not reduce the number of elements. This can happen if each element is individually within limits but the number of elements causes the collection to exceed the maximum size for the column.

FILLER datatype

Reads but does not copy the data of an input column. Use filler columns to ignore input columns that do not have columns in the table. You can also use filler columns to transform data (see Examples and Transforming data during loads). Filler columns cannot be of complex types.

If a filler column has the same name as a column in the table, you must explicitly scope other uses of the name in the COPY statement. To refer to an ambiguous filler column, prefix the name with "*FILLER*".:

=> COPY names(first FILLER VARCHAR, last, 
   full AS "*FILLER*".first||' '||last) FROM ...;

FORMAT 'format'

Input format, one of the following:

octal
hex
bitstream

See Binary (native) data to learn more about these formats.

When loading date/time columns, using FORMAT significantly improves load performance. COPY supports the same formats as the TO_DATE function. See Template patterns for date/time formatting.

If you specify invalid format strings, the COPY operation returns an error.

NULL [AS]

The string representing a null value. The default is an empty string (''). You can specify a null value as any ASCII value in the range E'\000' to E'\177' inclusive. You cannot use the same character for both the DELIMITER and NULL options. For details, see Delimited data.

Input options

The following options are available for specifying source data:

LOCAL

Loads data files (up to 4,294,967,295 files) on a client system, rather than on a cluster host. LOCAL can qualify the STDIN and path-to-data arguments. For details, see COPY LOCAL.

Restrictions: Invalid for CREATE EXTERNAL TABLE AS COPY

STDIN

Reads from the client a standard input instead of a file. STDIN takes one input source only. To load multiple input sources, use path-to-data.

User must have INSERT privileges on the table and USAGE privileges on its schema.

Restrictions: Invalid for CREATE EXTERNAL TABLE AS COPY

path-to-data

Specifies the absolute path of the file (or files) containing the data, which can be from multiple input sources.

If the file is stored in HDFS, path-to-data is a URI in the webhdfs scheme, typically [[s]web]hdfs://[nameservice]/path. See HDFS file system.
If the file is stored in an S3 bucket, path-to-data is a URI in the format s3://bucket/path. See S3 object store.
If the file is stored in Google Cloud Storage, path-to-data is a URI in the format gs://bucket/path. See Google Cloud Storage (GCS) object store.
If the file is stored in Azure Blob Storage, path-to-data is a URI in the format azb://account/container/path. See Azure Blob Storage object store.
If the file is on the local Linux file system or an NFS mount, path-to-data is a local absolute file path.

path-to-data can optionally contain wildcards to match more than one file. The file or files must be accessible to the local client or the host on which the COPY statement runs. COPY skips empty files in the file list. A file list that includes directories causes the query to fail. See Specifying where to load data from. The supported patterns for wildcards are specified in the Linux Manual Page for Glob (7), and for ADO.net platforms, through the .NET Directory.getFiles method.

You can use variables to construct the pathname as described in Using load scripts.

If path-to-data resolves to a storage location on a local file system, and the user invoking COPY is not a superuser, the following requirements apply:

The storage location was created with CREATE LOCATION...USAGE USER.
The user must already have READ access to the file storage location.

Further, if a user has privileges but is not a superuser, and invokes COPY from that storage location, the database ensures that symbolic links do not result in unauthorized access.

PARTITION COLUMNS column[,...]

Columns whose values are specified in the directory structure and not in the data itself.

For Hive-style partitioning, paths contain directory names of the form form colname=value, and COPY parses values for the specified partition columns. If a value is missing or cannot be coerced to the column data type, the source path is rejected.
For other partition schemes, column expressions specify how to extract values using the CURRENT_LOAD_SOURCE function. If the expression cannot be evaluated, the source path is rejected.

For more information, see Partitioned data.

ON nodename

Specifies the node on which the data to copy resides and the node that should parse the load file. If you omit nodename, the location of the input file defaults to the initiator node. Use nodename to copy and parse a load file from a node other than the COPY initiator node.

Note

nodename is invalid with STDIN and LOCAL.

ON (nodeset)

Specifies a set of nodes on which to perform the load. The same data must be available for load on all named nodes. nodeset is a comma-separated list of node names in parentheses. For example:

=> COPY t FROM 'file1.txt' ON (v_vmart_node0001, v_vmart_node0002);

The database apportions the load among all of the specified nodes. If you also specify ERROR TOLERANCE or REJECTMAX, the database instead chooses a single node on which to perform the load.

If the data is available on all nodes, you usually use ON ANY NODE, which is the default for loads from HDFS and cloud object stores. However, you can use ON nodeset to do manual load-balancing among concurrent loads.

ON ANY NODE

Specifies that the data to load is available on all nodes, so COPY opens the path and parses it from any node in the cluster. For an Eon Mode database, COPY uses nodes within the same subcluster as the initiator.

Caution

The data must be the same on all nodes. If the data differs on two nodes, an incorrect or incomplete result is returned, with no error or warning.

The database attempts to apportion the load among several nodes if a file is large enough to benefit from apportioning. It chooses a single node if ERROR TOLERANCE or REJECTMAX is specified.

You can use a wildcard or glob (such as *.dat) to load multiple input files, combined with the ON ANY NODE clause. If you use a glob, COPY distributes the list of files to all cluster nodes and spreads the workload.

ON ANY NODE is invalid with STDIN and LOCAL. STDIN can only use the client host, and LOCAL indicates a client node.

ON ANY NODE is the default for loads from all paths other than Linux (HDFS and cloud object stores).

ON EACH NODE

Loads data from the specified path on each node. Use this option when the path exists on all nodes but the data files it contains are different on each node. If the path is not valid on all nodes, COPY loads the valid paths and produces a warning. If the path is a shared location, COPY loads it only once as for ON ANY NODE.

compression

The input compression type, one of the following:

UNCOMPRESSED (default)
BZIP
GZIP
LZO
ZSTD

Input files can be of any format. If you use wildcards, all qualifying input files must be in the same format. To load different file formats, specify the format types specifically.

The following requirements and restrictions apply:

When using concatenated BZIP or GZIP files, verify that all source files terminate with a record terminator before concatenating them.
Concatenated BZIP and GZIP files are not supported for NATIVE (binary) and NATIVE VARCHAR formats.
LZO files are assumed to be compressed with lzop. The database supports the following lzop arguments:
- --no-checksum / -F
- --crc32
- --adler32
- --no-name / -n
- --name / -N
- --no-mode
- --no-time
- --fast
- --best
- Numbered compression levels
BZIP, GZIP, ZSTD, and LZO compression cannot be used with ORC format.

VERTICA

See COPY FROM VERTICA.

[WITH] UDL-clause[...]

Specifies one or more user-defined load functions—one source, and optionally one or more filters and one parser, as follows:

SOURCE source( [arg=value[,...] ]
[ FILTER filter( [arg=value[,...] ] ) ]...
[ PARSER parser( [arg=value[,...] ] ) ]

To use a flex table parser for column tables, use the PARSER parameter followed by a flex table parser argument. For supported flex table parsers, see Bulk loading data into flex tables.

Handling options

The following options control how COPY handles different contingencies:

ABORT ON ERROR

Specifies that COPY stops if any row is rejected. The statement is rolled back and no data is loaded.

COLSIZES (integer[,...])

Specifies column widths when loading fixed-width data. COPY requires that you specify COLSIZES when using the FIXEDWIDTH parser. COLSIZES and the list of integers must correspond to the columns listed in the table column list. For details, see Fixed-width format data.

ERROR TOLERANCE

Specifies that COPY treats each source during execution independently when loading data. The statement is not rolled back if a single source is invalid. The invalid source is skipped and the load continues.

Using this parameter disables apportioned load.

Restrictions: Invalid for ORC or Parquet data

EXCEPTIONS { 'path' [ ON nodename ] [,...]

Exceptions, used in combination with REJECTED DATA, describe why each rejected row was rejected. Each exception row corresponds to a rejection row.

This option specifies the file name or absolute path of the output file for exceptions. If the file already exists, it is overwritten.

Files are written on the node or nodes executing the load or, if ON is used, on the designated node. You cannot specify a path on a shared file system or qualify the path with ON ANY NODE. For more information, see Saving load exceptions (EXCEPTIONS).

To collect exceptions together with the rejected rows, use REJECTED DATA AS TABLE. You cannot use EXCEPTIONS with REJECTED DATA AS TABLE.

If you use this option with COPY...ON ANY NODE, you must still specify the individual nodes for the exception files, as in the following example:

EXCEPTIONS '/home/ex01.txt' on v_db_node0001,'/home/ex02.txt'
on v_db_node0002,'/home/ex03.txt' on v_db_node0003

If path resolves to a storage location, non-superusers have the following requirements:

The storage location must be created with the USER option (see CREATE LOCATION).
The user must have READ access to the storage location where the files exist, as described in GRANT (storage location).

REJECTED DATA { 'path' [ ON nodename ] [,...] | AS TABLE reject-table

Specifies where to write each row that failed to load. If this option is specified, records that failed due to parsing errors are always written. Records that failed due to an error during a transformation are written only if the CopyFaultTolerantExpressions configuration parameter is set.

The database can write rejected data to the local file system or to a table:

Local file system: The database writes rejected row data to the specified path on the node or nodes executing the load or, if ON is used, on the designated node. You cannot specify a path on a shared file system or qualify the path with ON ANY NODE. To make rejected data available on all nodes, write rejections to a table.

The value of path can be a directory or a file prefix. If there are multiple load sources, path is always treated as a directory. If there are not multiple load sources but path ends with '/', or if a directory of that name already exists, it is also treated as a directory. Otherwise, path is treated as a file prefix.

If the output file already exists, it is overwritten.

When REJECTED DATA with a path is used with LOCAL, the output is written to the client.
Table: The database writes rejected row data and exceptions to a table. You cannot use this option with EXCEPTIONS.

Writing rejections to a table is generally the better option, because they can then be queried from any node. If rejected data needs to be available from outside of the database, you can write it to a table and then export that table to a shared file system.

For more information about both options, see Handling messy data.

REJECTMAX integer

The maximum number of logical records that can be rejected before a load fails. For details, see Handling messy data.

REJECTMAX disables apportioned load.

SKIP integer

The number of records to skip in a load file. For example, you can use the SKIP option to omit table header information.

Restrictions: Invalid for ORC or Parquet data

STREAM NAME

Supplies a COPY load stream identifier. Using a stream name helps to quickly identify a particular load. The STREAM NAME value that you supply in the load statement appears in the STREAM_NAME column of system tables LOAD_STREAMS and LOAD_SOURCES.

A valid stream name can contain any combination of alphanumeric or special characters up to 128 bytes in length.

For example:

=> COPY mytable FROM myfile 
   DELIMITER '|' STREAM NAME 'My stream name';

WITH parser

Specifies the parser to use when bulk loading columnar tables, one of the following:

NATIVE
NATIVE VARCHAR
FIXEDWIDTH
ORC
PARQUET

By default, COPY uses the DELIMITER parser for UTF-8 format, delimited text input data. You do not specify the DELIMITER parser directly; absence of a specific parser indicates the default.

To use a flex table parser for column tables, use the PARSER parameter followed by a flex table parser argument. For supported flex table parsers, see Bulk loading data into flex tables.

When loading into flex tables, you must use a compatible parser. For supported flex table parsers, see Bulk loading data into flex tables.

COPY LOCAL does not support the NATIVE, NATIVE VARCHAR, ORC, and PARQUET parsers.

For parser support for complex data types, see the documentation of the specific parser.

For parser details, see Data formats in Data load.

NO COMMIT

Prevents the COPY statement from committing its transaction automatically when it finishes copying data. This option must be the last COPY statement parameter. For details, see Using transactions to stage a load.

This option is ignored by CREATE EXTERNAL TABLE AS COPY.

Parser-specific options

The following options apply only when using specific parsers.

DELIMITED parser

DELIMITER

Indicates the single ASCII character used to separate columns within each record of a file. You can use any ASCII value in the range E'\000' to E'\177', inclusive. You cannot use the same character for both the DELIMITER and NULL parameters. For more information, see Delimited data.

Default: Vertical bar ('|').

ENCLOSED [BY]

Sets the quote character within which to enclose data, allowing delimiter characters to be embedded in string values. You can choose any ASCII value in the range E'\001' to E'\177' inclusive (any ASCII character except NULL: E'\000'). By default, ENCLOSED BY has no value, meaning data is not enclosed by any sort of quote character.

ESCAPE [AS]

Sets the escape character. Once set, the character following the escape character is interpreted literally, rather than as a special character. You can define an escape character using any ASCII value in the range E'\001' to E'\177', inclusive (any ASCII character except NULL: E'\000').

The COPY statement does not interpret the data it reads in as String literals. It also does not follow the same escape rules as other SQL statements (including the COPY parameters). When reading data, COPY interprets only the characters defined by these options as special values:

ESCAPE [AS]
DELIMITER
ENCLOSED [BY]
RECORD TERMINATOR
All COLLECTION options

Default: Backslash ('\').

NO ESCAPE

Eliminates escape-character handling. Use this option if you do not need any escape character and you want to prevent characters in your data from being interpreted as escape sequences.

RECORD TERMINATOR

Specifies the literal character string indicating the end of a data file record. For more information about using this parameter, see Delimited data.

TRAILING NULLCOLS

Specifies that if Vertica encounters a record with insufficient data to match the columns in the table column list, COPY inserts the missing columns with NULL values. For other information and examples, see Fixed-width format data.

COLLECTIONDELIMITER

For columns of collection types, indicates the single ASCII character used to separate elements within each collection. You can use any ASCII value in the range E'\000' to E'\177', inclusive. No COLLECTION option may have the same value as any other COLLECTION option. For more information, see Delimited data.

Default: Comma (',').

COLLECTIONOPEN, COLLECTIONCLOSE

For columns of collection types, these options indicate the characters that mark the beginning and end of the collection. It is an error to use these characters elsewhere within the list of elements without escaping them. No COLLECTION option may have the same value as any other COLLECTION option.

Default: Square brackets ('[' and ']').

COLLECTIONNULLELEMENT

The string representing a null element value in a collection. You can specify a null value as any ASCII value in the range E'\001' to E'\177' inclusive (any ASCII value except NULL: E'\000'). No COLLECTION option may have the same value as any other COLLECTION option. For more information, see Delimited data.

Default: 'null'

COLLECTIONENCLOSE

For columns of collection types, sets the quote character within which to enclose individual elements, allowing delimiter characters to be embedded in string values. You can choose any ASCII value in the range E'\001' to E'\177' inclusive (any ASCII character except NULL: E'\000').

No COLLECTION option may have the same value as any other COLLECTION option.

Default: double quote ('"')

FIXEDWIDTH parser

SKIP BYTES integer: The total number of bytes in a record to skip.
TRIM: Trims the number of bytes you specify from a column. This option is only available when loading fixed-width data. You can set TRIM at the table level for a column, or as part of the COLUMN OPTION parameter.

Sql-Reference: Restrictions

Mon, 01 Jan 0001 00:00:00 +0000

COPY has the following restrictions:

Invalid data

COPY considers the following data invalid:

Missing columns (an input line has fewer columns than the recipient table).
Extra columns (an input line has more columns than the recipient table).
Empty columns for an INTEGER or DATE/TIME data type. If a column is empty for either of these types, COPY does not use the default value that was defined by CREATE TABLE. However, if you do not supply a column option as part of the COPY statement, the default value is used.
Incorrect representation of a data type. For example, trying to load a non-numeric value into an INTEGER column is invalid.

Constraint violations

If primary key, unique key, or check constraints are enabled for automatic enforcement in the target table, the database enforces those constraints when you load new data. If a violation occurs, the database rolls back the operation and returns an error.

Empty line handling

When COPY encounters an empty line while loading data, the line is neither inserted nor rejected, but COPY increments the line record number. Consider this behavior when evaluating rejected records. If you return a list of rejected records and COPY encountered an empty row while loading data, the position of rejected records is not incremented by one, as demonstrated in the following example.

The example first loads values into a table that defines the first column as INT. Note the errors on rows 3, 4, and 8:

=> \! cat -n /home/dbadmin/test.txt
     1 1|A|2
     2 2|B|4
     3 A|D|7
     4 A|E|7
     5
     6
     7 6|A|3
     8 B|A|3

The empty rows (5 and 6) shift the reporting of the error on row 8:

=> SELECT row_number, rejected_data, rejected_reason FROM test_bad;
 row_number | rejected_data | rejected_reason
------------+---------------+----------------------------------------------
          3 | A|D|7 | Invalid integer format 'A' for column 1 (c1)
          4 | A|E|7 | Invalid integer format 'A' for column 1 (c1)
          6 | B|A|3 | Invalid integer format 'B' for column 1 (c1)
(3 rows)

Compressed file errors

When loading compressed files, COPY might abort and report an error, if the file seems to be corrupted. For example, this behavior can occur if reading the header block fails.

Disk quota

Tables and schemas can have disk quotas. If a load would violate either quota, the operation fails. For more information, see Disk quotas.

Sql-Reference: Parsers

Mon, 01 Jan 0001 00:00:00 +0000

OpenText™ Analytics Database supports several parsers to load different types of data. Some parsers are for use only with flex tables, as noted.

Sql-Reference: Examples

Mon, 01 Jan 0001 00:00:00 +0000

For additional COPY examples, see the reference pages for specific parsers, including: DELIMITED, ORC, PARQUET, FJSONPARSER, and FAVROPARSER.

Specifying string options

Use COPY with FORMAT, DELIMITER, NULL, and ENCLOSED BY options:

=> COPY public.customer_dimension (customer_since FORMAT 'YYYY')
   FROM STDIN
   DELIMITER ','
   NULL AS 'null'
   ENCLOSED BY '"';

This example sets and references a vsql variable for the input file:

=> \set input_file ../myCopyFromLocal/large_table.gzip
=> COPY store.store_dimension
   FROM :input_file
   DELIMITER '|'
   NULL ''
   RECORD TERMINATOR E'\f';

Including multiple source files

Create a table and then copy multiple source files to it:

=> CREATE TABLE sampletab (a int);
CREATE TABLE

=> COPY sampletab FROM '/home/dbadmin/one.dat', 'home/dbadmin/two.dat';
 Rows Loaded
-------------
           2
(1 row)

Use wildcards to indicate a group of files:

=> COPY myTable FROM 'webhdfs:///mydirectory/ofmanyfiles/*.dat';

Wildcards can include regular expressions:

=> COPY myTable FROM 'webhdfs:///mydirectory/*_[0-9]';

Specify multiple paths in a single COPY statement:

=> COPY myTable FROM 'webhdfs:///data/sales/01/*.dat', 'webhdfs:///data/sales/02/*.dat',
    'webhdfs:///data/sales/historical.dat';

Distributing a load

Load data that is shared across all nodes. OpenText™ Analytics Database distributes the load across all nodes, if possible:

=> COPY sampletab FROM '/data/file.dat' ON ANY NODE;

Load data from two files. Because the first load file does not specify nodes (or ON ANY NODE), the initiator performs the load. Loading the second file is distributed across all nodes:

=> COPY sampletab FROM '/data/file1.dat', '/data/file2.dat' ON ANY NODE;

Specify different nodes for each load file:

=> COPY sampletab FROM '/data/file1.dat' ON (v_vmart_node0001, v_vmart_node0002),
    '/data/file2.dat' ON (v_vmart_node0003, v_vmart_node0004);

Loading data from shared storage

To load data from shared storage, use URLs in the corresponding schemes:

HDFS: [[s]web]hdfs://[nameservice]/path
S3: s3://bucket/path
Google Cloud: gs://bucket/path
Azure: azb://account/container/path

Note

Loads from HDFS, S3, GCS, and Azure default to ON ANY NODE; you do not need to specify it.

Load a file stored in HDFS using the default name node or name service:

=> COPY t FROM 'webhdfs:///opt/data/file1.dat';

Load data from a particular HDFS name service (testNS). You specify a name service if your database is configured to read from more than one HDFS cluster:

=> COPY t FROM 'webhdfs://testNS/opt/data/file2.csv';

Load data from an S3 bucket:

=> COPY t FROM 's3://AWS_DataLake/*' ORC;

Partitioned data

Data files can be partitioned using the directory structure, such as:

path/created=2016-11-01/region=northeast/*
path/created=2016-11-01/region=central/*
path/created=2016-11-01/region=southeast/*
path/created=2016-11-01/...
path/created=2016-11-02/region=northeast/*
path/created=2016-11-02/region=central/*
path/created=2016-11-02/region=southeast/*
path/created=2016-11-02/...
path/created=2016-11-03/...
path/...

Load partition columns using the PARTITION COLUMNS option:

=> CREATE EXTERNAL TABLE records (id int, name varchar(50), created date, region varchar(50))
   AS COPY FROM 'webhdfs:///path/*/*/*'
   PARTITION COLUMNS created, region;

Using filler columns

In the following example, the table has columns for first name, last name, and full name, but the data being loaded contains columns for first, middle, and last names. The COPY statement reads all of the source data but only loads the source columns for first and last names. It constructs the data for the full name by concatenating each of the source data columns, including the middle name. The middle name is read as a FILLER column so it can be used in the concatenation, but is ignored otherwise. (There is no table column for middle name.)

=> CREATE TABLE names(first VARCHAR(20), last VARCHAR(20), full VARCHAR(60));
CREATE TABLE
=> COPY names(first,
              middle FILLER VARCHAR(20),
              last,
              full AS first||' '||middle||' '||last)
      FROM STDIN;
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> Marc|Gregory|Smith
>> Sue|Lucia|Temp
>> Jon|Pete|Hamilton
>> \.
=> SELECT * from names;
 first |   last   |        full
-------+----------+--------------------
 Jon   | Hamilton | Jon Pete Hamilton
 Marc  | Smith    | Marc Gregory Smith
 Sue   | Temp     | Sue Lucia Temp
(3 rows)

In the following example, JSON data contains an unencrypted password. The JSON data and the table definition use the same name for the field. Instead of loading the value directly, the COPY statement uses a filler column and a (hypothetical) function to encrypt the value. Both the table column (users.password) and the filler column ("*FILLER*".password) are fully qualified:

=> CREATE TABLE users(user VARCHAR(32), password VARCHAR(32));

=> COPY users(user, password FILLER VARCHAR(32),
        users.password AS encrypt("*FILLER*".password))
   FROM ... PARSER FJSONPARSER();

Setting defaults for null values

When creating a table, you can specify a default value for a column. When loading data, the database uses the default if the column value is not present. However, defaults do not override null values.

To intercept null values and apply defaults, you can first stage the load with COPY NO COMMIT and then update the values:

=> CREATE TABLE sales (id INT, shipped TIMESTAMP(6) DEFAULT now());

=> COPY sales FROM ... NO COMMIT;

=> UPDATE sales SET shipped = DEFAULT WHERE epoch IS NULL;

=> COMMIT;

All database tables have an implicit epoch column, which records when the data was committed. For data that is not yet committed, this value is null. You can use this column to identify the just-loaded data and update it before committing.

Loading data into a flex table

Create a Flex table and copy JSON data into it:

=> CREATE FLEX TABLE darkdata();
CREATE TABLE
=> COPY tweets FROM '/myTest/Flexible/DATA/tweets_12.json' PARSER FJSONPARSER();
 Rows Loaded
-------------
          12
(1 row)

Using named pipes

COPY supports named pipes that follow the same naming conventions as file names on the given file system. Permissions are open, write, and close.

Create a named pipe and set two vsql variables:

=> \! mkfifo  pipe1
=> \set dir `pwd`/
=> \set file '''':dir'pipe1'''

Copy an uncompressed file from the named pipe:

=> \! cat pf1.dat > pipe1 &
=> COPY large_tbl FROM :file delimiter '|';
=> SELECT * FROM large_tbl;
=> COMMIT;

Loading compressed data

Copy a GZIP file from a named pipe and uncompress it:

=> \! gzip pf1.dat
=> \! cat pf1.dat.gz > pipe1 &
=> COPY large_tbl FROM :file ON site01 GZIP delimiter '|';
=> SELECT * FROM large_tbl;
=> COMMIT;
=> \!gunzip pf1.dat.gz