Posts Tagged ‘psql’

How Data-Pipeline’s RDS to Redshift copy template works ? (and limitations)

Written by mannem on March 3, 2016. Posted in Data Pipelines

The template contains 4 Activities.

1. RDSToS3CopyActivity – Creates a CSV file in S3 based on mySQL table.
2. RedshiftTableCreateActivity – Translates MySQL table to PSQL and creates a table(if it does not exist).
3. S3ToRedshiftCopyActivity – Runs a Redshift COPY command.
4. S3StagingCleanupActivity – Cleans up the staging S3 directory.

RedshiftTableCreateActivity is the key activity and where all the complexity lies.

It runs a shell script using ShellCommandActivity which Translates the MySQL table structure to Psql syntax , and creates a table on Redshift with translated table structure. the data-type translation between RDS and Redhsift is provided here

http://docs.aws.amazon.com/datapipeline/latest/DeveloperGuide/dp-template-redshift.html
Now, if you dig more into the ShellCommandActivity, The conversion script is downloaded as part of s3://datapipeline-us-east-1/sample-scripts/dbconv.sh , which in-turn downloads the translator python script

curl -O https://s3.amazonaws.com/datapipeline-us-east-1/sample-scripts/mysql_to_redshift.py

You can check out the contents of this script on how exactly it translates.

Ex:

mysql> create table TestTable (Id int not null , Lname varchar(20));

According to translation table , this activity , translates to a psql script , which runs on the ec2 instance.

[ec2-user@ip-172-31-1-122 ~]$ cat red0303180850.psql
-- Converted by MySql to Redshift db converter
START TRANSACTION;
 CREATE TABLE RedshiftTarget (Id int not null , Lname varchar(80));
COMMIT;

[ec2-user@ip-172-31-1-122 ~]$ cat red0303180850.psql

-- Converted by MySql to Redshift db converter

START TRANSACTION;

CREATE TABLE RedshiftTarget (Id int not null , Lname varchar(80));

COMMIT;

Make note of limitations on this script while using it !

mysql_to_redshift.py :

__author__ = 'ramaraa'

#!/usr/bin/env python

"""
Fixes a MySQL dump made with the right format so it can be
imported to a Redshift database.

Dump using:
mysqldump --compatible=postgresql --default-character-set=utf8 -r databasename.mysql -u root databasename tablename

"""

import re
import sys
import os
import time
import getopt


def file_len(filename):
    """
    Returns the equivalent of wc - l
    :param filename: file name
    :return: number of lines in the file
    """
    with open(filename) as f:
        i = 0
        for i, l in enumerate(f):
            pass
    return i + 1


def parse(input_filename, output_filename, table_name, distribution_key, redshift_sort_keys, type_map):
    # State storage
    """
    Feed it a mysqldump file, and it'll output a redshift equivalent one.
    Optional params specified here are designed for mysqldump containing only one table definition


    :rtype : void
    :param input_filename: input mysqldump file
    :param output_filename:
    :param table_name: optional. generated table name for the first table encountered, else the same as input.
    :param distribution_key: optional. distribution key column in redshift for the first table encountered.
    :param redshift_sort_keys: optional. sort key(s) column(s) in redshift for the first table encountered.
    :param type_map: optional. override type conversion from mysql to redshift.
                     tinyint(1):smallint,char(35):varchar(70),bigint(20) unsigned:bigint
    :param insert_mode: optional. https://docs.aws.amazon.com/console/datapipeline/redshiftcopyactivity.
        Determines how to handle pre-existing data in the target table that overlaps with rows in the data to be loaded.
        "allowedValues": [ "OVERWRITE_EXISTING", "KEEP_EXISTING", "TRUNCATE"]
        if insert_mode is OVERWRITE_EXISTING and distribution_key not specified, first primary key is set as dist key.
    """
    if input_filename == "-":
        num_lines = -1
    else:
        num_lines = int(file_len(input_filename))
    tables = {}
    current_table = None
    creation_lines = []
    foreign_key_lines = []
    num_inserts = 0
    started = time.time()
    table_primary_key_not_done = True

    # Open output file and write header. Logging file handle will be std out
    # unless we're writing output to std out, in which case NO PROGRESS FOR YOU.
    if output_filename == "-":
        output = sys.stdout
        logging = open(os.devnull, "w")
    else:
        output = open(output_filename, "w")
        logging = sys.stdout

    if input_filename == "-":
        input_fh = sys.stdin
    else:
        input_fh = open(input_filename)

    output.write("-- Converted by MySql to Redshift db converter\n")
    output.write("START TRANSACTION;\n")

    for i, line in enumerate(input_fh):
        time_taken = time.time() - started
        percentage_done = (i + 1) / float(num_lines)
        secs_left = (time_taken / percentage_done) - time_taken
        logging.write("\rLine %i (of %s: %.2f%%) [%s tables] [%s inserts] [ETA: %i min %i sec]" % (
            i + 1,
            num_lines,
            ((i + 1) / float(num_lines)) * 100,
            len(tables),
            num_inserts,
            secs_left // 60,
            secs_left % 60,
        ))
        logging.flush()

        line = line.decode("utf8").strip()
        # Ignore comment lines
        if line.startswith("--") or line.startswith("/*") or line.startswith("LOCK TABLES") or line.startswith(
                "DROP TABLE") or line.startswith("UNLOCK TABLES") or not line:
            continue

        # Outside of anything handling
        if current_table is None:
            # Start of a table creation statement?
            if line.startswith("CREATE TABLE"):
                # current_table is the table name in MySQL
                current_table = line.split('"')[1]
                if table_name and not table_name.isspace():
                    logging.write("\rLine %i [Encountered table %s ] [Generated table name %s]" % (
                        i + 1, current_table, table_name))
                    current_table = table_name
                    table_name = None
                tables[current_table] = {"columns": []}
                creation_lines = []
                table_primary_key_not_done = True
            # Inserting data into a table?
            elif line.startswith("INSERT INTO"):
                output.write(line.encode("utf8").replace("'0000-00-00 00:00:00'", "NULL") + "\n")
                num_inserts += 1
            # ???
            else:
                print "\n ! Ignore. Unknown line in main body: %s" % line

        # Inside-create-statement handling
        else:
            # Is it a column?
            if line.startswith('"'):
                useless, name, definition = line.strip(",").split('"', 2)
                try:
                    sql_type, extra = definition.strip().split(" ", 1)

                    # This must be a tricky enum
                    if ')' in extra:
                        sql_type, extra = definition.strip().split(")")

                except ValueError:
                    sql_type = definition.strip()
                    extra = ""

                # check if extra contains unsigned
                unsigned = "unsigned" in extra.lower()
                # remove unsigned now
                extra = re.sub("CHARACTER SET [\w\d]+\s*", "", extra.replace("unsigned", ""))
                extra = re.sub("COLLATE [\w\d]+\s*", "", extra.replace("unsigned", ""))
                extra = extra.replace("AUTO_INCREMENT", "")
                extra = extra.replace("SERIAL", "")
                extra = extra.replace("ZEROFILL", "")
                extra = extra.replace("UNSIGNED", "")
                sql_type = sql_type.lower()

                if type_map is not None and sql_type in type_map:
                    red_type = type_map[sql_type]
                elif type_map is not None and unsigned and sql_type+ " unsigned" in type_map:
                    red_type = type_map[sql_type+ " unsigned"]
                elif sql_type == "tinyint(1)":
                    red_type = "boolean"
                elif sql_type.startswith("tinyint("):
                    red_type = "smallint"
                elif sql_type.startswith("smallint("):
                    if unsigned:
                        red_type = "integer"
                    else:
                        red_type = "smallint"
                elif sql_type.startswith("mediumint("):
                    red_type = "integer"
                elif sql_type.startswith("int("):
                    if unsigned:
                        red_type = "bigint"
                    else:
                        red_type = "integer"
                elif sql_type.startswith("bigint("):
                    if unsigned:
                        red_type = "varchar(80)"
                    else:
                        red_type = "bigint"
                elif sql_type.startswith("float"):
                    red_type = "real"
                elif sql_type.startswith("double"):
                    red_type = "double precision"
                elif sql_type.startswith("decimal"):
                    # same decimal
                    red_type = sql_type
                elif sql_type.startswith("char("):
                    size = int(sql_type.split("(")[1].rstrip(")"))
                    red_type = "varchar(%s)" % (size * 4)
                elif sql_type.startswith("varchar("):
                    size = int(sql_type.split("(")[1].rstrip(")"))
                    red_type = "varchar(%s)" % (size * 4)
                elif sql_type == "longtext":
                    red_type = "varchar(max)"
                elif sql_type == "mediumtext":
                    red_type = "varchar(max)"
                elif sql_type == "tinytext":
                    red_type = "text(%s)" % (255 * 4)
                elif sql_type == "text":
                    red_type = "varchar(max)"
                elif sql_type.startswith("enum(") or sql_type.startswith("set("):
                    red_type = "varchar(%s)" % (255 * 2)
                elif sql_type == "blob":
                    red_type = "varchar(max)"
                elif sql_type == "mediumblob":
                    red_type = "varchar(max)"
                elif sql_type == "longblob":
                    red_type = "varchar(max)"
                elif sql_type == "tinyblob":
                    red_type = "varchar(255)"
                elif sql_type.startswith("binary"):
                    red_type = "varchar(255)"
                elif sql_type == "date":
                    # same
                    red_type = sql_type
                elif sql_type == "time":
                    red_type = "varchar(40)"
                elif sql_type == "datetime":
                    red_type = "timestamp"
                elif sql_type == "year":
                    red_type = "varchar(16)"
                elif sql_type == "timestamp":
                    # same
                    red_type = sql_type
                else:
                    # all else, e.g., varchar binary
                    red_type = "varchar(max)"

                # Record it
                creation_lines.append('"%s" %s %s' % (name, red_type, extra))
                tables[current_table]['columns'].append((name, red_type, extra))
            # Is it a constraint or something?
            elif line.startswith("PRIMARY KEY"):
                #composite primary key not supported in redshift
                if table_primary_key_not_done:
                    #aws datapipeline redshift copy only supports 1 primary key. remove this restriction after that is fixed
                    #creation_lines.append(line.rstrip(","))
                    first_pkey = line.rstrip(",").rstrip(")").lstrip("PRIMARY KEY").lstrip("(\"").split(",")[0].rstrip("\"")
                    pkey_line ='PRIMARY KEY("' + first_pkey + '")'
                    creation_lines.append(pkey_line)
                    if not distribution_key:
                        distribution_key = first_pkey
                    table_primary_key_not_done = False
            elif line.startswith("CONSTRAINT"):
                # Try adding foreign key in a different transaction. If it fails, no big deal.
                foreign_key_lines.append("ALTER TABLE \"%s\" ADD CONSTRAINT %s DEFERRABLE INITIALLY DEFERRED" % (
                    current_table, line.split("CONSTRAINT")[1].strip().rstrip(",")))
                # No need for index on foreign key column as Redshift does not support indexes
            elif line.startswith("UNIQUE KEY"):
                creation_lines.append("UNIQUE (%s)" % line.split("(")[1].split(")")[0])
            elif line.startswith("FULLTEXT KEY"):
                # No indexes in Redshift
                pass
            elif line.startswith("KEY"):
                pass
            # Is it the end of the table?
            elif line == ");":
                output.write("CREATE TABLE IF NOT EXISTS \"%s\" (\n" % current_table)
                for j, outline in enumerate(creation_lines):
                    output.write("    %s%s\n" % (outline, "," if j != (len(creation_lines) - 1) else ""))
                output.write(')\n')
                if distribution_key and not distribution_key.isspace():
                    output.write('distkey(%s)\n' % distribution_key)
                    distribution_key = None
                if redshift_sort_keys and not redshift_sort_keys.isspace():
                    output.write('sortkey(%s)\n' % redshift_sort_keys)
                    redshift_sort_keys = None
                output.write(';\n\n')
                current_table = None
            # ???
            else:
                print "\n ! Ignore. Unknown line inside table creation: %s" % line

    # Finish file
    output.write("COMMIT;\n")

    #output.write("START TRANSACTION;\n")
    # Write FK constraints out
    #output.write("\n-- Foreign keys --\n")
    #for line in foreign_key_lines:
    #    output.write("%s;\n" % line)
    # Finish file
    #output.write("\n")
    #output.write("COMMIT;\n")

    print ""


def usage():
    print("Usage: %s -i input -o output [-t table_name] [-d DistKey] [-s SortKey1,SortKey2...] "
          "[-m MySQL1:RedType1,MySQL2:RedType2...]" % sys.argv[0])


if __name__ == "__main__":

    input_file = ''
    output_file = ''
    gen_table_name = None
    dist_key = None
    sort_keys = None
    map_types = None
    insert_mode = None

    try:
        opts, args = getopt.getopt(sys.argv[1:], "i:o:t:d:s:m:n:",
                                   ["input_file=", "output_file=", "table_name=", "dist_key=", "sort_keys=",
                                    "map_types=", "insert_mode="])
    except getopt.GetoptError as e:
        print (str(e))
        usage()
        sys.exit(2)

    for opt, arg in opts:
        if opt in ("-i", "--input_file"):
            input_file = arg
        elif opt in ("-o", "--output_file"):
            output_file = arg
        elif opt in ("-t", "--table_name"):
            gen_table_name = arg
        elif opt in ("-d", "--dist_key"):
            dist_key = arg
        elif opt in ("-s", "--sort_keys"):
            sort_keys = arg
        elif opt in ("-m", "--map_types"):
            map_types = arg
        elif opt in ("-n", "--insert_mode"):
            insert_mode = arg

    map_types_dict = None
    if map_types and not map_types.isspace():
        map_types_dict_temp = dict([arg.split(':') for arg in map_types.lower().lstrip().split(',')])
        #sanitize keys to strip whitespaces
        map_types_dict = dict()
        for key in map_types_dict_temp:
            map_types_dict[key.lstrip().rstrip()] = map_types_dict_temp[key]

    parse(input_file, output_file, gen_table_name, dist_key, sort_keys, map_types_dict)
    sys.exit(0)

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__author__ = 'ramaraa'

#!/usr/bin/env python

"""

Fixes a MySQL dump made with the right format so it can be

imported to a Redshift database.

Dump using:

mysqldump --compatible=postgresql --default-character-set=utf8 -r databasename.mysql -u root databasename tablename

"""

import re

import sys

import os

import time

import getopt

def file_len(filename):

"""

Returns the equivalent of wc - l

:param filename: file name

:return: number of lines in the file

"""

with open(filename) as f:

i = 0

for i, l in enumerate(f):

pass

return i + 1

def parse(input_filename, output_filename, table_name, distribution_key, redshift_sort_keys, type_map):

# State storage

"""

Feed it a mysqldump file, and it'll output a redshift equivalent one.

Optional params specified here are designed for mysqldump containing only one table definition

:rtype : void

:param input_filename: input mysqldump file

:param output_filename:

:param table_name: optional. generated table name for the first table encountered, else the same as input.

:param distribution_key: optional. distribution key column in redshift for the first table encountered.

:param redshift_sort_keys: optional. sort key(s) column(s) in redshift for the first table encountered.

:param type_map: optional. override type conversion from mysql to redshift.

tinyint(1):smallint,char(35):varchar(70),bigint(20) unsigned:bigint

:param insert_mode: optional. https://docs.aws.amazon.com/console/datapipeline/redshiftcopyactivity.

Determines how to handle pre-existing data in the target table that overlaps with rows in the data to be loaded.

"allowedValues": [ "OVERWRITE_EXISTING", "KEEP_EXISTING", "TRUNCATE"]

if insert_mode is OVERWRITE_EXISTING and distribution_key not specified, first primary key is set as dist key.

"""

if input_filename == "-":

num_lines = -1

else:

num_lines = int(file_len(input_filename))

tables = {}

current_table = None

creation_lines = []

foreign_key_lines = []

num_inserts = 0

started = time.time()

table_primary_key_not_done = True

# Open output file and write header. Logging file handle will be std out

# unless we're writing output to std out, in which case NO PROGRESS FOR YOU.

if output_filename == "-":

output = sys.stdout

logging = open(os.devnull, "w")

else:

output = open(output_filename, "w")

logging = sys.stdout

if input_filename == "-":

input_fh = sys.stdin

else:

input_fh = open(input_filename)

output.write("-- Converted by MySql to Redshift db converter\n")

output.write("START TRANSACTION;\n")

for i, line in enumerate(input_fh):

time_taken = time.time() - started

percentage_done = (i + 1) / float(num_lines)

secs_left = (time_taken / percentage_done) - time_taken

logging.write("\rLine %i (of %s: %.2f%%) [%s tables] [%s inserts] [ETA: %i min %i sec]" % (

i + 1,

num_lines,

((i + 1) / float(num_lines)) * 100,

len(tables),

num_inserts,

secs_left // 60,

secs_left % 60,

))

logging.flush()

line = line.decode("utf8").strip()

# Ignore comment lines

if line.startswith("--") or line.startswith("/*") or line.startswith("LOCK TABLES") or line.startswith(

"DROP TABLE") or line.startswith("UNLOCK TABLES") or not line:

continue

# Outside of anything handling

if current_table is None:

# Start of a table creation statement?

if line.startswith("CREATE TABLE"):

# current_table is the table name in MySQL

current_table = line.split('"')[1]

if table_name and not table_name.isspace():

logging.write("\rLine %i [Encountered table %s ] [Generated table name %s]" % (

i + 1, current_table, table_name))

current_table = table_name

table_name = None

tables[current_table] = {"columns": []}

creation_lines = []

table_primary_key_not_done = True

# Inserting data into a table?

elif line.startswith("INSERT INTO"):

output.write(line.encode("utf8").replace("'0000-00-00 00:00:00'", "NULL") + "\n")

num_inserts += 1

# ???

else:

print "\n ! Ignore. Unknown line in main body: %s" % line

# Inside-create-statement handling

else:

# Is it a column?

if line.startswith('"'):

useless, name, definition = line.strip(",").split('"', 2)

try:

sql_type, extra = definition.strip().split(" ", 1)

# This must be a tricky enum

if ')' in extra:

sql_type, extra = definition.strip().split(")")

except ValueError:

sql_type = definition.strip()

extra = ""

# check if extra contains unsigned

unsigned = "unsigned" in extra.lower()

# remove unsigned now

extra = re.sub("CHARACTER SET [\w\d]+\s*", "", extra.replace("unsigned", ""))

extra = re.sub("COLLATE [\w\d]+\s*", "", extra.replace("unsigned", ""))

extra = extra.replace("AUTO_INCREMENT", "")

extra = extra.replace("SERIAL", "")

extra = extra.replace("ZEROFILL", "")

extra = extra.replace("UNSIGNED", "")

sql_type = sql_type.lower()

if type_map is not None and sql_type in type_map:

red_type = type_map[sql_type]

elif type_map is not None and unsigned and sql_type+ " unsigned" in type_map:

red_type = type_map[sql_type+ " unsigned"]

elif sql_type == "tinyint(1)":

red_type = "boolean"

elif sql_type.startswith("tinyint("):

red_type = "smallint"

elif sql_type.startswith("smallint("):

if unsigned:

red_type = "integer"

else:

red_type = "smallint"

elif sql_type.startswith("mediumint("):

red_type = "integer"

elif sql_type.startswith("int("):

if unsigned:

red_type = "bigint"

else:

red_type = "integer"

elif sql_type.startswith("bigint("):

if unsigned:

red_type = "varchar(80)"

else:

red_type = "bigint"

elif sql_type.startswith("float"):

red_type = "real"

elif sql_type.startswith("double"):

red_type = "double precision"

elif sql_type.startswith("decimal"):

# same decimal

red_type = sql_type

elif sql_type.startswith("char("):

size = int(sql_type.split("(")[1].rstrip(")"))

red_type = "varchar(%s)" % (size * 4)

elif sql_type.startswith("varchar("):

size = int(sql_type.split("(")[1].rstrip(")"))

red_type = "varchar(%s)" % (size * 4)

elif sql_type == "longtext":

red_type = "varchar(max)"

elif sql_type == "mediumtext":

red_type = "varchar(max)"

elif sql_type == "tinytext":

red_type = "text(%s)" % (255 * 4)

elif sql_type == "text":

red_type = "varchar(max)"

elif sql_type.startswith("enum(") or sql_type.startswith("set("):

red_type = "varchar(%s)" % (255 * 2)

elif sql_type == "blob":

red_type = "varchar(max)"

elif sql_type == "mediumblob":

red_type = "varchar(max)"

elif sql_type == "longblob":

red_type = "varchar(max)"

elif sql_type == "tinyblob":

red_type = "varchar(255)"

elif sql_type.startswith("binary"):

red_type = "varchar(255)"

elif sql_type == "date":

# same

red_type = sql_type

elif sql_type == "time":

red_type = "varchar(40)"

elif sql_type == "datetime":

red_type = "timestamp"

elif sql_type == "year":

red_type = "varchar(16)"

elif sql_type == "timestamp":

# same

red_type = sql_type

else:

# all else, e.g., varchar binary

red_type = "varchar(max)"

# Record it

creation_lines.append('"%s" %s %s' % (name, red_type, extra))

tables[current_table]['columns'].append((name, red_type, extra))

# Is it a constraint or something?

elif line.startswith("PRIMARY KEY"):

#composite primary key not supported in redshift

if table_primary_key_not_done:

#aws datapipeline redshift copy only supports 1 primary key. remove this restriction after that is fixed

#creation_lines.append(line.rstrip(","))

first_pkey = line.rstrip(",").rstrip(")").lstrip("PRIMARY KEY").lstrip("(\"").split(",")[0].rstrip("\"")

pkey_line ='PRIMARY KEY("' + first_pkey + '")'

creation_lines.append(pkey_line)

if not distribution_key:

distribution_key = first_pkey

table_primary_key_not_done = False

elif line.startswith("CONSTRAINT"):

# Try adding foreign key in a different transaction. If it fails, no big deal.

foreign_key_lines.append("ALTER TABLE \"%s\" ADD CONSTRAINT %s DEFERRABLE INITIALLY DEFERRED" % (

current_table, line.split("CONSTRAINT")[1].strip().rstrip(",")))

# No need for index on foreign key column as Redshift does not support indexes

elif line.startswith("UNIQUE KEY"):

creation_lines.append("UNIQUE (%s)" % line.split("(")[1].split(")")[0])

elif line.startswith("FULLTEXT KEY"):

# No indexes in Redshift

pass

elif line.startswith("KEY"):

pass

# Is it the end of the table?

elif line == ");":

output.write("CREATE TABLE IF NOT EXISTS \"%s\" (\n" % current_table)

for j, outline in enumerate(creation_lines):

output.write(" %s%s\n" % (outline, "," if j != (len(creation_lines) - 1) else ""))

output.write(')\n')

if distribution_key and not distribution_key.isspace():

output.write('distkey(%s)\n' % distribution_key)

distribution_key = None

if redshift_sort_keys and not redshift_sort_keys.isspace():

output.write('sortkey(%s)\n' % redshift_sort_keys)

redshift_sort_keys = None

output.write(';\n\n')

current_table = None

# ???

else:

print "\n ! Ignore. Unknown line inside table creation: %s" % line

# Finish file

output.write("COMMIT;\n")

#output.write("START TRANSACTION;\n")

# Write FK constraints out

#output.write("\n-- Foreign keys --\n")

#for line in foreign_key_lines:

# output.write("%s;\n" % line)

# Finish file

#output.write("\n")

#output.write("COMMIT;\n")

print ""

def usage():

print("Usage: %s -i input -o output [-t table_name] [-d DistKey] [-s SortKey1,SortKey2...] "

"[-m MySQL1:RedType1,MySQL2:RedType2...]" % sys.argv[0])

if __name__ == "__main__":

input_file = ''

output_file = ''

gen_table_name = None

dist_key = None

sort_keys = None

map_types = None

insert_mode = None

try:

opts, args = getopt.getopt(sys.argv[1:], "i:o:t:d:s:m:n:",

["input_file=", "output_file=", "table_name=", "dist_key=", "sort_keys=",

"map_types=", "insert_mode="])

except getopt.GetoptError as e:

print (str(e))

usage()

sys.exit(2)

for opt, arg in opts:

if opt in ("-i", "--input_file"):

input_file = arg

elif opt in ("-o", "--output_file"):

output_file = arg

elif opt in ("-t", "--table_name"):

gen_table_name = arg

elif opt in ("-d", "--dist_key"):

dist_key = arg

elif opt in ("-s", "--sort_keys"):

sort_keys = arg

elif opt in ("-m", "--map_types"):

map_types = arg

elif opt in ("-n", "--insert_mode"):

insert_mode = arg

map_types_dict = None

if map_types and not map_types.isspace():

map_types_dict_temp = dict([arg.split(':') for arg in map_types.lower().lstrip().split(',')])

#sanitize keys to strip whitespaces

map_types_dict = dict()

for key in map_types_dict_temp:

map_types_dict[key.lstrip().rstrip()] = map_types_dict_temp[key]

parse(input_file, output_file, gen_table_name, dist_key, sort_keys, map_types_dict)

sys.exit(0)

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Running complex queries on redshift with Data-pipelines

Written by mannem on December 5, 2015. Posted in Data Pipelines, Redshift

Sometimes AWS Data-Pipelines SQLActivity may not support complex queries. This is because Data-Pieplines SqlActivity passes this script to JDBS executeStatement(Prepared statement). This script is supposed to be idempotent. So here’s an alternative to run psql/sql commands using Data-Pipelines.

Suppose you have the following psql command,

select 'insert into event_data_' ||to_char(current_date,'yyyymm')|| '_v2 select * from stage_event_data_v2 where event_time::date >= '''||to_char(current_date, 'YYYY-MM')||'-01'' and event_time::date <= '''||last_day(current_date)||''';';

and it should output,

insert into event_data_201511_v2 select * from stage_event_data_v2 where event_time::date >= '2015-11-01' and event_time::date <= '2015-11-30';

This is a valid command in psql and can be successfully executed with workbenches and psql shell.

But using Data-pipelines, executing the above command will throw and error:

ERROR processing query/statement. Error: Parsing failed

This is because the script appears to be changing(not idempotent) when it is executed.

If you have a complex redshift commands and wish to performing operations against Redshift that involve custom logic. You could rather write a program in your favorite language and run it
using ShellCommandActivity. This is a quite valid way of interacting with Redshift.

There are several ways to do this. I am including a shell script and its Data-pipelne template as a reference here.

Sample shell command:

#----A sample shell code to run psql queries----
#!/bin/bash -x
sudo yum install postgresql -y
sudo yum install aws-cli -y
export PGPASSWORD=$2
scriptFile=$(aws s3 ls $1 --region us-west-2 | awk '{print $4}')
aws s3 cp $1 /home/ec2-user/ --region us-west-2
psql -h redshift.rkcloud.us -p 5439 -d rkevents -U rkevents -f /home/ec2-user/$scriptFile -o /home/ec2-user/v2.sql -t
aws s3 cp /home/ec2-user/v2.sql s3://bucket/ --region us-west-2
#-------------------------------------------------

#----A sample shell code to run psql queries----

#!/bin/bash -x

sudo yum install postgresql -y

sudo yum install aws-cli -y

export PGPASSWORD=$2

scriptFile=$(aws s3 ls $1 --region us-west-2 | awk '{print $4}')

aws s3 cp $1 /home/ec2-user/ --region us-west-2

psql -h redshift.rkcloud.us -p 5439 -d rkevents -U rkevents -f /home/ec2-user/$scriptFile -o /home/ec2-user/v2.sql -t

aws s3 cp /home/ec2-user/v2.sql s3://bucket/ --region us-west-2

#-------------------------------------------------

Sample Data-pipelines template:

{
  "objects": [
    {
      "schedule": {
        "ref": "DefaultSchedule"
      },
      "instanceType": "t1.micro",
      "name": "EC2ResourceObj",
      "id": "EC2ResourceObj",
      "type": "Ec2Resource",
      "terminateAfter": "20 Minutes"
    },
    {
      "schedule": {
        "ref": "DefaultSchedule"
      },
      "scriptUri": "s3://YourBucket/shellCommands.sh",
      "name": "ShellCommandActivityObj",
      "scriptArgument": [
        "s3://YourBucket/event_data_yyyymm.sql",
        "#{*myRedshiftPass}"
      ],
      "id": "ShellCommandActivityObj",
      "runsOn": {
        "ref": "EC2ResourceObj"
      },
      "type": "ShellCommandActivity"
    },
    {
      "failureAndRerunMode": "CASCADE",
      "resourceRole": "DataPipelineDefaultResourceRole",
      "role": "DataPipelineDefaultRole",
      "pipelineLogUri": "s3://yourLogBucket/",
      "scheduleType": "cron",
      "name": "Default",
      "id": "Default"
    },
    {
      "occurrences": "1",
      "period": "1 Hour",
      "name": "MyRunOnce",
      "id": "DefaultSchedule",
      "type": "Schedule",
      "startAt": "FIRST_ACTIVATION_DATE_TIME"
    }
  ],
  "parameters": [
    {
      "description": "Redhift password",
      "id": "*myRedshiftPass"
    }
  ],
  "values": {
    "*myRedshiftPass": "MyRedshiftPass123"
  }
}

{

"objects": [

{

"schedule": {

"ref": "DefaultSchedule"

"instanceType": "t1.micro",

"name": "EC2ResourceObj",

"id": "EC2ResourceObj",

"type": "Ec2Resource",

"terminateAfter": "20 Minutes"

{

"schedule": {

"ref": "DefaultSchedule"

"scriptUri": "s3://YourBucket/shellCommands.sh",

"name": "ShellCommandActivityObj",

"scriptArgument": [

"s3://YourBucket/event_data_yyyymm.sql",

"#{*myRedshiftPass}"

"id": "ShellCommandActivityObj",

"runsOn": {

"ref": "EC2ResourceObj"

"type": "ShellCommandActivity"

{

"failureAndRerunMode": "CASCADE",

"resourceRole": "DataPipelineDefaultResourceRole",

"role": "DataPipelineDefaultRole",

"pipelineLogUri": "s3://yourLogBucket/",

"scheduleType": "cron",

"name": "Default",

"id": "Default"

{

"occurrences": "1",

"period": "1 Hour",

"name": "MyRunOnce",

"id": "DefaultSchedule",

"type": "Schedule",

"startAt": "FIRST_ACTIVATION_DATE_TIME"

}

"parameters": [

{

"description": "Redhift password",

"id": "*myRedshiftPass"

}

"values": {

"*myRedshiftPass": "MyRedshiftPass123"

}

-------------------------------------------------
Some info on the script and Data-pipeline:

1. This script file has 2 arguments (Arg 1 is the sql script that you need to execute , Arg 2 is the Redshift password). These arguments are provided in Data-pipeline shellCommandActivity object using scriptArgument field.

2. The script outputs its result to v2.sql and uploads to s3 bucket (with -t tuples only option), so that you can run the script later.

3. The Data-pipeline template uses the *myRedshiftPass parameter id to hide the password from DataPipelines.
-------------------------------------------------

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