Some Iceberg Basics for Beginners (CDP).pdf
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The document describes the recommended Iceberg workflow which includes 8 steps: 1) Create Iceberg tables from existing datasets or sample datasets 2) Batch insert data to prepare for time travel scenarios 3) Create security policies for fine-grained access control 4) Build BI queries for reporting 5) Build visualizations from query results 6) Perform time travel queries to audit changes 7) Optimize partition schemas to improve query performance 8) Manage and expire snapshots for table maintenance
![Table Conversion SQL commands /
Utility [Tech Preview]](https://image.slidesharecdn.com/someicebergbasicsforbeginnerscdp-221201120023-3a81ac89/85/Some-Iceberg-Basics-for-Beginners-CDP-pdf-8-320.jpg)
![Table Maintenance [ Tech Preview ]](https://image.slidesharecdn.com/someicebergbasicsforbeginnerscdp-221201120023-3a81ac89/85/Some-Iceberg-Basics-for-Beginners-CDP-pdf-16-320.jpg)
![© 2022 Cloudera, Inc. All rights reserved. 17
Table Maintenance [ Tech Preview ]
Time Travel Ops Examples
Hive / Impala
Query
// Tentative, Proposed Syntax, not in GA
// Expires snapshots that are older than 7 days.
ALTER TABLE test_table EXECUTE expire_snapshots_lt
(now() - interval 7
days);
Spark Scala API // Not in GA
// Expires snapshots that are older than 7 day
Table test_table = …
long tsToExpire = System.currentTimeMillis() - (1000*60*60*24*7);
test_table.expireSnapshots()
.expireOlderThan(tsToExpire)
.commit();
Expiring old snapshots removes them from metadata, so they are no longer available for time travel operations. Data files are
not deleted until they are no longer referenced by a snapshot that may be used for time travel. Regularly expiring snapshots
deletes unused data files.](https://image.slidesharecdn.com/someicebergbasicsforbeginnerscdp-221201120023-3a81ac89/85/Some-Iceberg-Basics-for-Beginners-CDP-pdf-17-320.jpg)
Some Iceberg Basics for Beginners (CDP).pdf
- 1. HOW to use First steps
- 2. © 2022 Cloudera, Inc. All rights reserved. 2 Recommended Iceberg Workflow Create Iceberg tables a. Bring your own datasets by converting your Hive external tables OR b. Use the sample airline datasets CDW: Hive CDE: Spark SQL 1 Batch Insert data To prepare Time Travel scenario: Insert more data into Iceberg tables with Hive or Spark CDE: Spark SQL 2 Create Security Policy Create a Ranger policy to mask a column for Fine Grained Access Control (FGAC) SDX: Ranger 3 Build BI Query Create SQL Queries for standard ops. reporting CDW: Impala SQL 4 Build Visualizations Create data sets & Visuals from Query CDV: Create data set from query & Build Visuals 5 Perform Time Travel Create Time Travel Queries and Execute them to audit what has changed CDW: Hive/Impala SQL CDE: Spark Scala API 6 Partition Evolution Optimize partition schema to improve query performance CDW: Hive/Impala SQL CDE: Spark SQL 7 Table Maintenance Manage / Expire Snapshots CDE: Spark SQL 8 CREATE INGEST/ PREP SERVE OPERATION / MAINTENANCE GOVERN
- 3. © 2022 Cloudera, Inc. All rights reserved. 3 SQL Commands ( Hive, Spark, Impala)
- 4. © 2022 Cloudera, Inc. All rights reserved. 4 SQL Commands Iceberg Tables T a b l e C o n v e r s i o n Tim e Travel DDL Query D M L Ease of Use through consistent SQL Syntax across compute engines Rich set of SQL commands are developed for Hive, Impala and Spark to • Create and manipulate database objects • Run Queries • Load data into tables • Modify data in tables • Perform Time Travel operations • Convert to Iceberg tables
- 5. © 2022 Cloudera, Inc. All rights reserved. 5 Snapshot of Iceberg SQL Commands Hive Impala Spark Select ⬤ ⬤ ⬤ DML (INSERT INTO, INSERT OVERWRITE) ⬤ ⬤ ⬤ Create Table ⬤ ⬤ ⬤ Alter Table ⬤ ⬤ ⬤ Drop Table ⬤ ⬤ ⬤ Truncate Table ⬤ ⬤ NA Create-Table-As-Select ⬤ ⬤ ⬤ Replace-Table-As-Select NA NA ⬤ Partition Evolution ⬤ ⬤ ⬤ Partition Transformation ⬤ ⬤ ⬤ Schema Evolution ⬤ ⬤ ⬤ Table Metadata (DESCRIBE TABLE, SHOW CREATE TABLE) ⬤ ⬤ ⬤ Time Travel ⬤ ⬤ Scala API now, SQL is planned Table Migration ⬤ NA ⬤ Table Maintenance NA NA ⬤ ⬤ General Availability ⬤ Tech Preview
- 6. Compute Engines Interoperability & Fine Grained Access Control
- 7. © 2022 Cloudera, Inc. All rights reserved. 7 Compute Engine Interoperability & FGAC ❏ Consistent Iceberg table access and processing with SQL using Hive, Spark and Impala (reads and writes) ❏ No partial reads ❏ No adapters needed ❏ Iceberg FGAC support through Ranger integration with Hive / Impala ❏ Spark is planned ❏ Compatible with existing workflows ❏ Optimized for performance, cost and developer efficiency Iceberg Tables Apache Impala
- 8. Table Conversion SQL commands / Utility [Tech Preview]
- 9. © 2022 Cloudera, Inc. All rights reserved. 9 Table Conversion from Hive External to Iceberg Tables 1. Hive table migration: ALTER TABLE tbl SET TBLPROPERTIES (‘storage_handler’=’org.apache.iceberg.mr.hive.HiveIcebergStorageHandler’) 2. Spark 3: a. Import Hive tables into Iceberg spark.sql("CALL <catalog>.system.snapshot('<src>', '<dest>')") b. Migrate Hive tables to Iceberg tables spark.sql("CALL <catalog>.system.migrate('<src>')")
- 11. © 2022 Cloudera, Inc. All rights reserved. 11 Time Travel t Time Travel is the ability to make a query reproducible at a given snapshot and/or time Time Travel operations: ● SELECT … AS OF … Apache Impala Snapshot A Snapshot Z Standard SQL operations: ● Queries ● DDL ● DML t | | T 0
- 12. © 2022 Cloudera, Inc. All rights reserved. 12 Time Travel Operations Time Travel Ops SQL Examples Hive / Impala Query SELECT * FROM table FOR SYSTEM_TIME AS OF ’2021-08-09 10:35:57’; SELECT * FROM table FOR SYSTEM_VERSION AS OF 1234567; Spark Scala API // time travel to snapshot with ID 10963874102873L spark.read .option("snapshot-id", 10963874102873L) .format("iceberg") .load("path/to/table") // time travel to October 26, 1986 at 01:21:00 spark.read .option("as-of-timestamp", "499162860000") .format("iceberg") .load("path/to/table")
- 14. © 2022 Cloudera, Inc. All rights reserved. 14 In-place Partition Evolution ❏ Existing big data solution doesn’t support in-place partition evolution. Entire table must be completely rewritten with new partition column ❏ With Iceberg’s hidden partition, a separation between physical and logical, users are not required to maintain partition columns. ❏ Iceberg tables can evolve partition schemas over time as data volume changes. ❏ Benefits: ❏ No costly table rewrites or table migration ❏ No query rewrites ❏ Reduce downtime and improve SLA 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 2022-01-01 t Partitions included in query plan Partitioned by Month(date) Partitioned by Day(date) 2021-10-01 2021-11-01 2021-12-01 2022-01… SELECT * FROM SALES_ORDER WHERE DATE > 2021-11-23 AND DATA < 2022-01-19 Split plan 1 Split plan 2
- 15. © 2022 Cloudera, Inc. All rights reserved. 15 Partition Evolution SQL examples Engine SQL Examples Hive / Impala // Partition evolution to hour ALTER TABLE t SET PARTITION SPEC (hour(ts)) Spark SQL // Partition evolution to hour ALTER TABLE t ADD PARTITION FIELD (hour(ts))
- 16. Table Maintenance [ Tech Preview ]
- 17. © 2022 Cloudera, Inc. All rights reserved. 17 Table Maintenance [ Tech Preview ] Time Travel Ops Examples Hive / Impala Query // Tentative, Proposed Syntax, not in GA // Expires snapshots that are older than 7 days. ALTER TABLE test_table EXECUTE expire_snapshots_lt (now() - interval 7 days); Spark Scala API // Not in GA // Expires snapshots that are older than 7 day Table test_table = … long tsToExpire = System.currentTimeMillis() - (1000*60*60*24*7); test_table.expireSnapshots() .expireOlderThan(tsToExpire) .commit(); Expiring old snapshots removes them from metadata, so they are no longer available for time travel operations. Data files are not deleted until they are no longer referenced by a snapshot that may be used for time travel. Regularly expiring snapshots deletes unused data files.