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https://issues.apache.org/jira/browse/IGNITE-6917?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16347230#comment-16347230
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Alexander Paschenko edited comment on IGNITE-6917 at 1/31/18 5:28 PM:
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[~kirill.shirokov],
Regarding 7.2 - yes, please disregard empty columns list. Suppose there's _key
and _val.
Regarding empty lines - they are always added for readability but we don't add
them right after line ending with {, be it method or class declaration or loop
or switch. Yes, with long method declarations this may not look good, but for
consistency let's stick with what I suggest, thanks.
Regarding 5 - ok, Vlad's always right. Still IMHO main thing is not simpler
code but better usability here. (Just saying.)
was (Author: al.psc):
[~kirill.shirokov],
Regarding 7.2 - yes, please disregard empty columns list. Suppose there's _key
and _val.
Regarding empty fields - they are always added for readability but we don't add
them right after line ending with {, be it method or class declaration or loop
or switch. Yes, with long method declarations this may not look good, but for
consistency let's stick with what I suggest, thanks.
Regarding 5 - ok, Vlad's always right. Still IMHO main thing is not simpler
code but better usability here. (Just saying.)
> SQL: implement COPY command for efficient data loading
> ------------------------------------------------------
>
> Key: IGNITE-6917
> URL: https://issues.apache.org/jira/browse/IGNITE-6917
> Project: Ignite
> Issue Type: New Feature
> Components: sql
> Reporter: Vladimir Ozerov
> Assignee: Kirill Shirokov
> Priority: Major
> Labels: iep-1
>
> Inspired by Postgres [1]
> Common use case - bulk data load through JDBC/ODBC interface. Currently it is
> only possible to execute single commands one by one. We already can batch
> them to improve performance, but there is still big room for improvement.
> We should think of a completely new command - {{COPY}}. It will accept a file
> (or input stream in general case) on the client side, then transfer data to
> the cluster, and then execute update inside the cluster, e.g. through
> streamer.
> First of all we need to create quick and dirty prototype to assess potential
> performance improvement. It speedup is confirmed, we should build base
> implementation which will accept only files. But at the same time we should
> understand how it will evolve in future: multiple file formats (probably
> including Hadoop formarts, e.g. Parquet), escape characters, input streams,
> etc..
> [1] [https://www.postgresql.org/docs/9.6/static/sql-copy.html]
> h1. Proposed syntax
> Curent implementation:
> {noformat}
> COPY
> FROM "file.name"
> INTO <schema>.<table>
> [(col-name, ...)]
> FORMAT <format-name> -- Only CSV format is supported in the current
> release
> [BATCH_SIZE <batch-size-in-bytes>]
> {noformat}
> We may want to gradually add features to this command in future to have
> something like this:
> {noformat}
> COPY
> FROM "file.name"[CHARSET "<charset-name>"]
> INTO <schema>.<table> [CREATE [IF NOT EXISTS]]
> [(col-name [<data-type>] [NULLABLE] [ESCAPES], ...) [MATCH HEADER]]
> FORMAT (csv|tsv|...)
> -- CSV format options:
> [FIELDSEP='column-separators-regexp']
> [LINESEP='row-separators-regexp']
> [QUOTE='quote-chars']
> [ESCAPE='escape-char']
> [NULL='null-sequence']
> [COMMENT='single-line-comment-start-char']
> [TRIM_LINES]
> [IMPORT_EMPTY_LINES]
> [CHARSET "<charset-name>"]
> [ROWS <first>-<last>]
> --or--
> [SKIP ROWS <num>] [MAX ROWS <num>]
> [COLS <first>-<last>]
> --or--
> [SKIP COLS <num>] [MAX COLS <num>]
> [(MATCH | SKIP) HEADER]
> [(REPLACE|IGNORE|ABORT ON [<max-error-number>])) DUPLICATE KEYS]
> [BATCH SIZE (<num> ROWS | <num>[K|M|G|T|P])]
> [COMPRESS "codec-name" [codec options]]
> [LOCK (TABLE|ROWS)]
> [NOLOGGING]
> [BACKEND (DIRECT | STREAMER)]
> {noformat}
> h1. Implementation decisions and notes
> h2. Parsing
> * We support CSV format described in RFC 4180.
> * Custom row and column separators, quoting characters are currently hardcoded
> * Escape sequences, line comment characters are currently not supported
> * We may want to support fixed-length formats (via format descriptors) in
> future
> * We may want to strip comments from lines (for example, starting with '#')
> * We may want to allow user to either ignore empty lines or treat them as a
> special case of record having all default values
> * We may allow user to enable whitespace trimming from beginning and end of a
> line
> * We may want to allow user to specify error handling strategy: e.g., only
> one quote character is present or escape sequence is invalid.
> h2. File handling
> * File character set to be supported in future
> * Skipped/imported row number (or first/last line or skip header option),
> skipped/imported column number (or first/last column): to be supported in
> future
> * Line start pattern (as in MySQL): no support planned
> * We currently support only client-side import. No server-side file import.
> * We may want to support client-side stdin import in future.
> * We do not handle importing multiple files from single command
> * We don't benefit from any kind of pre-sorting pre-partitioning data on
> client side.
> * We don't include any any metadata, such as line number from client side.
> h3. Transferring data
> * We send file data via batches. In future we will support batch size
> (specified with rows per batch or data block size
> per batch).
> * We may want to implement data compression in future.
> * We connect to single node in JDBC driver (no multi-node connections).
> h3. Cache/tables/column handling
> * We don't create table in the bulk load command
> * We may want to have and option for reading header row, which contains
> column names to match columns
> * In future we may wish to support COLUMNS (col1, _, col2, _, col3) syntax,
> where '_' marker means a skipped column (MySQL uses '@dummy' for this)
> h3. Data types
> * Data types are converted as if they were supplied to INSERT SQL command.
> * We may want type conversion (automatic, custom using sql function, custom
> via Java code, string auto-trimming) in future.
> * We will support optional null sequence ("\N") later
> * We may want to allow user to specify what to do if the same record exists
> (e.g., ignore record, replace it, report error with a max. error counter
> before failing the command)
> * We don't currently support any generated/autoincremented row IDs or any
> custom generators.
> * We don't support any filtering/conditional expressions
> * We don't support any files/recordsets/tables with multiple conversion
> errors generated during import.
> h3. Backend / Transactional / MVCC / other
> * We may want an option to select how do we insert the data into cache: using
> cache.putAll(...), for example, or via data streamer interface (see BACKEND
> option)
> * We don't use transactions
> * We don't create locks on rows or tables.
> * We don't try to minimize any indexing overhead (it's up to the user)
> * We may want to minimize WAL impact in future via NOLOGGING option.
> h3. Miscellanea
> * We don't supply an utility to load data
> * We don't currently supply any java loaders (as in PG and MSSQL) that stream
> data (not neccessary from file)
> * Security-related questions are out of scope of this JIRA
> * We don't have triggers and constraints in Apache Ignite
> h1. Implementations from other vendors
> h2. PostgreSQL
> {noformat}
> COPY table_name [ ( column_name [, ...] ) ]
> FROM { 'filename' | STDIN }
> [ [ WITH ]
> [ BINARY ]
> [ OIDS ]
> [ DELIMITER [ AS ] 'delimiter' ]
> [ NULL [ AS ] 'null string' ]
> [ CSV [ HEADER ]
> [ QUOTE [ AS ] 'quote' ]
> [ ESCAPE [ AS ] 'escape' ]
> [ FORCE NOT NULL column_name [, ...] ] ] ]
> {noformat}
> ([https://www.postgresql.org/docs/9.2/static/sql-copy.html])
> h3. Notes
> * Server-side file import
> * Client-side: only from STDIN
> * Protocol implementation: via special command in the protocol
> * Special bulk data loaders in implemented as part of JDBC driver package:
> org.postgresql.copy.CopyManager
>
> ([https://jdbc.postgresql.org/documentation/publicapi/org/postgresql/copy/CopyManager.html])
> * Custom loaders available (e.g.,
> [https://github.com/bytefish/PgBulkInsert.git])
> h2. MySQL
> {noformat}
> LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name'
> [REPLACE | IGNORE]
> INTO TABLE tbl_name
> [PARTITION (partition_name [, partition_name] ...)]
> [CHARACTER SET charset_name]
> [{FIELDS | COLUMNS}
> [TERMINATED BY 'string']
> [[OPTIONALLY] ENCLOSED BY 'char']
> [ESCAPED BY 'char']
> ]
> [LINES
> [STARTING BY 'string']
> [TERMINATED BY 'string']
> ]
> [IGNORE number {LINES | ROWS}]
> [(col_name_or_user_var
> [, col_name_or_user_var] ...)]
> [SET col_name={expr | DEFAULT},
> [, col_name={expr | DEFAULT}] ...]
> {noformat}
> ([https://dev.mysql.com/doc/refman/5.7/en/load-data.html])
> h3. Notes
> * Both client- and server-side import
> * Protocol implementation via a hack: if result set returned with column
> count == -1, read file name from server and send it immediately.
> h2. Microsoft SQL Server
> {noformat}
> BULK INSERT
> [ database_name . [ schema_name ] . | schema_name . ] [ table_name |
> view_name ]
> FROM 'data_file'
> [ WITH
> (
> [ [ , ] BATCHSIZE = batch_size ]
> [ [ , ] CHECK_CONSTRAINTS ]
> [ [ , ] CODEPAGE = { 'ACP' | 'OEM' | 'RAW' | 'code_page' } ]
> [ [ , ] DATAFILETYPE =
> { 'char' | 'native'| 'widechar' | 'widenative' } ]
> [ [ , ] DATASOURCE = 'data_source_name' ]
> [ [ , ] ERRORFILE = 'file_name' ]
> [ [ , ] ERRORFILE_DATASOURCE = 'data_source_name' ]
> [ [ , ] FIRSTROW = first_row ]
> [ [ , ] FIRE_TRIGGERS ]
> [ [ , ] FORMATFILE_DATASOURCE = 'data_source_name' ]
> [ [ , ] KEEPIDENTITY ]
> [ [ , ] KEEPNULLS ]
> [ [ , ] KILOBYTES_PER_BATCH = kilobytes_per_batch ]
> [ [ , ] LASTROW = last_row ]
> [ [ , ] MAXERRORS = max_errors ]
> [ [ , ] ORDER ( { column [ ASC | DESC ] } [ ,...n ] ) ]
> [ [ , ] ROWS_PER_BATCH = rows_per_batch ]
> [ [ , ] ROWTERMINATOR = 'row_terminator' ]
> [ [ , ] TABLOCK ]
> -- input file format options
> [ [ , ] FORMAT = 'CSV' ]
> [ [ , ] FIELDQUOTE = 'quote_characters']
> [ [ , ] FORMATFILE = 'format_file_path' ]
> [ [ , ] FIELDTERMINATOR = 'field_terminator' ]
> [ [ , ] ROWTERMINATOR = 'row_terminator' ]
> )]
> {noformat}
> ([https://docs.microsoft.com/en-us/sql/t-sql/statements/bulk-insert-transact-sql])
> h3. Notes
> * Server-side import
> * CLI utility to import from client side
> * Protocol implementation: Special packet types: column definition and row
> * Custom bulk data supplied in JDBC driver package:
> com.microsoft.sqlserver.jdbc.SqlServerBulkCopy.
> h2. Oracle
> There is no bulk load SQL command. Bulk loading external data can be achieved
> via:
> * Oracle External Tables
> ([https://docs.oracle.com/en/database/oracle/oracle-database/12.2/sutil/oracle-external-tables-concepts.html])
> * SQL*Loader
> ([https://docs.oracle.com/database/121/SUTIL/GUID-8D037494-07FA-4226-B507-E1B2ED10C144.htm#SUTIL3311]).
> * There is a separate utility for Oracle TimesTen in-memory database:
> [https://docs.oracle.com/database/121/TTREF/util.htm#TTREF324]
> h2. Vertica DB
> {noformat}
> COPY [ [db-name.]schema-name.]target-table
> ... [ ( { column-as-expression | column }
> ...... [ DELIMITER [ AS ] 'char' ]
> ...... [ ENCLOSED [ BY ] 'char' ]
> ...... [ ENFORCELENGTH ]
> ...... [ ESCAPE [ AS ] 'char' | NO ESCAPE ]
> ...... [ FILLER datatype]
> ...... [ FORMAT 'format' ]
> ...... [ NULL [ AS ] 'string' ]
> ...... [ TRIM 'byte' ]
> ... [, ... ] ) ]
> ... [ COLUMN OPTION ( column
> ...... [ DELIMITER [ AS ] 'char' ]
> ...... [ ENCLOSED [ BY ] 'char' ]
> ...... [ ENFORCELENGTH ]
> ...... [ ESCAPE [ AS ] 'char' | NO ESCAPE ]
> ...... [ FORMAT 'format' ]
> ...... [ NULL [ AS ] 'string' ]
> ...... [ TRIM 'byte' ]
> ... [, ... ] ) ]
> [ FROM {
> ...STDIN
> ...... [ BZIP | GZIP | LZO | UNCOMPRESSED ]
> ...| 'pathToData' [ ON nodename | ON ANY NODE ]
> ...... [ BZIP | GZIP | LZO | UNCOMPRESSED ] [, ...]
> ...| LOCAL {STDIN | 'pathToData'}
> ...... [ BZIP | GZIP | LZO | UNCOMPRESSED ] [, ...]
> ...| VERTICA source_database.[source_schema.]source_table[(source_column
> [,...]) ]
> } ]
> ...[ NATIVE
> .....| NATIVE VARCHAR
> .....| FIXEDWIDTH COLSIZES (integer [,...])
> .....| ORC
> .....| PARQUET
> ...]
> ...[ WITH ]
> ......[ SOURCE source([arg=value [,...] ]) ]
> ......[ FILTER filter([arg=value [,...] ]) ]
> ......[ PARSER parser([arg=value [,...] ]) ]
> ...[ DELIMITER [ AS ] 'char' ]
> ...[ TRAILING NULLCOLS ]
> ...[ NULL [ AS ] 'string' ]
> ...[ ESCAPE [ AS ] 'char' | NO ESCAPE ]
> ...[ ENCLOSED [ BY ] 'char' ]
> ...[ RECORD TERMINATOR 'string' ]
> ...[ SKIP records ]
> ...[ SKIP BYTES integer ]
> ...[ TRIM 'byte' ]
> ...[ REJECTMAX integer ]
> ...[ REJECTED DATA {'path' [ ON nodename ] [, ...] | AS TABLE reject-table} ]
> ...[ EXCEPTIONS 'path' [ ON nodename ] [, ...] ]
> ...[ ENFORCELENGTH ]
> ...[ ERROR TOLERANCE ]
> ...[ ABORT ON ERROR ]
> ...[ [ STORAGE ] load-method ]
> ...[ STREAM NAME 'streamName']
> ...[ NO COMMIT ]
> {noformat}
> ([https://my.vertica.com/docs/7.2.x/HTML/index.htm#Authoring/SQLReferenceManual/Statements/COPY/COPY.htm])
> h2. Various solutions from vendors not mentioned above
> * Apache Hive:
>
> [https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DML#LanguageManualDML-Loadingfilesintotables]
> * Apache HBase:
> [http://dwgeek.com/apache-hbase-bulk-load-csv-examples.html]
> * SAP IQ:
>
> [https://help.sap.com/viewer/a898a5b484f21015a377cd1ccb6ee9b5/16.0.11.12/en-US/a6209de484f21015bcb2d858c21ab35e.html]
> * VoltDB:
> [https://docs.voltdb.com/UsingVoltDB/clicsvloader.php]
> * MemSQL:
> [https://docs.memsql.com/sql-reference/v6.0/load-data/]
> (creating pipelines and connecting them to LOAD DATA statement is also a
> notable feature)
> * Sybase:
>
> [http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.sqlanywhere.12.0.1/dbreference/input-statement.html]
> * IBM DB2:
>
> [https://www.ibm.com/support/knowledgecenter/en/SSEPGG_9.5.0/com.ibm.db2.luw.admin.cmd.doc/doc/r0008305.html]
> * IBM Informix:
>
> [https://www.ibm.com/support/knowledgecenter/en/SSGU8G_12.1.0/com.ibm.sqls.doc/ids_sqs_0884.htm]
> * Apache Derby (AKA Java DB, Apache DB):
> [https://db.apache.org/derby/docs/10.7/tools/ttoolsimporting.html]
> * Google Cloud Spanner:
> [https://cloud.google.com/spanner/docs/bulk-loading]
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