clientid Dec 1, 2022 · I have a Merge into statement that I use to update existing entries or create new entries in a dimension table based on a natural business key. Previously, the MERGE INTO statement was commonly used for processing CDC records on Databricks. I have published a test notebook, but am unable to reproduce the issue. Compare cost. However, MERGE INTO can produce incorrect results because of out-of-sequence records, or require complex logic to re-order records. <path of delta table> oldData USING ( SELECT * FROM df WHERE year = '2023' AND month = '10' AND day = '12' ) newData ON oldData. You trigger compaction by running the OPTIMIZE command. while reading a table from Synapse into a datafrmae in Spark, driver will first make Synapse export data to Dec 23, 2022 · %sql MERGE INTO target as t USING source as s ON t. #list of table names tables = ['default. In this example, the partition columns (year, month, day) are used in the subquery in the USING clause to filter the data being merged. schema. 1 and above for delta file format; Apache Spark for hudi file format; dbt will run an atomic merge statement which looks nearly identical to the default merge Apr 18, 2024 · Applies to: Databricks SQL Databricks Runtime 10. Mer Spark 3. t1','default. enabled = true; create table if not exists catlog. unionByName(spark. Enabled Change Data Feed feature. Databricks Git folders provides source control for data and AI projects by integrating with Git providers. Attempting to add an additional field, or remove a field, causes any upcoming insert or update transaction on the table to fail, even if mergeSchema is Apr 24, 2024 · I want to use in-memory cached views in a merge into operation, but I am not entirely sure if the exactly saved in-memory view is used in this operation or not. When I run explain select * from cached_view_1 from the output I see that in-memory view is used: Dec 1, 2020 · You can also do this using a staging table in Synapse and use Synapse's compute to do the upsert instead of Spark's compute. Apply a merge with a dataframe that involves inserts, deletes, updates. June 12, 2024. Specify the join condition to match and combine the records. date_field WHEN MATCHED THEN UPDATE SET * WHEN NOT MATCHED THEN INSERT * WHEN NOT MATCHED BY SOURCE THEN DELETE') Inspect data. Databricks - Merge Into Snap is a write-type Snap that inserts and updates data in a DLP instance. Part 1: Loading zipped files into dataframe is running fine Mar 8, 2021 · MERGE allows column references in the OUTPUT clause that are not in the inserted table. See Upsert into a Delta Lake table using merge. That will be in a helper function, which specifies the number of streams to handle the tables in parallel with Auto Loader. Aug 25, 2022 · mergeのプログラム上のオペレーションの詳細な説明を以下に示します。 任意の数のwhenMatched、whenNotMatched句を追加することができます。 注意 Databricksランタイム7. WHEN MATCHED THEN DELETE -- Conditionally update target rows that have a match in the source table using the source value. key = target_table . UPDATE SET. Apr 26, 2024 · However, MERGE INTO can produce incorrect results because of out-of-sequence records, or require complex logic to re-order records. 04-25-2023 10:18 PM. Jan 11, 2023 · I have created new table with csv file with following code %sql SET spark. USING (VALUES()) // round brackets are required to denote a subquery. The data that is to be loaded into a table is validated but not written to the table. I added the third column for this post. spark. table with the output of it. Deleted = 1. , leading zeros, precision, and time zones are not as important as id correctly combining ‘ dt ’ & ‘ tm ’. However the merge into statement doesn't allow me to use `uuid()` . clientid = newData. month = '10' and oldData. date_field = t. FROM tmp. Jul 18, 2023 · create table default. Execute the merge query to perform the merge operation. Admittedly, the current query does not have that, but it is possible that other references were originally there or intended to be added. delta. Delta Lake on Azure Databricks can improve the speed of reading queries from a table. col0 WHEN MATCHED THEN UPDATE SET target. I'm having trouble with part 2 below. Read and write to/from Spark to/from Synapse using their driver uses Datalake as stage. Then i write another stream to apply some tranformations to union_stream and write it to union_stream2 (step 3). sql (f "" " SELECT YEAR, MONTH, DAY, COLLECT_LIST (DISTINCT TYPE) AS TYPES Incremental FROM GROUP BY YEAR, MONTH, DAY ORDER BY 1, 2, 3 "" ") . %sql. Sep 25, 2020 · SELECT id, country_code, fullname_1 AS fullname, firstname_1 AS firstname. When using a Delta table as a stream source, the query first processes all of the data present in the table. INSERT (id, Name, Deleted) VALUES (S. e. This statement is supported only for Delta Lake tables. This is a re-triable and idempotent operation; files in the source location that have already been loaded are skipped. 1 and is slashed for release in upcoming version of OSS Delta - 2. My results: I suppose one advantage over the flatMap technique is you don't have to specify the datatypes and it appears simpler on the face of it. A merge operation is a way to combine the commit history from one branch into another branch; the only difference is the strategy it uses to Feb 27, 2023 · SELECT * FROM df WHERE year = '2023' AND month = '10' AND day = '12'. This is a great trick to play on your unsuspecting coworkers. key = target_table. Suppose you have a source table named people10mupdates or a Mar 19, 2019 · Simplify building big data pipelines for change data capture (CDC) and GDPR use cases. tablename; COPY INTO catlog. col1 WHEN NOT MATCHED THEN INSERT (col0, col1) VALUES (source. In the meantime I found a workaround: explicitly set the column mapping Jan 13, 2023 · To do this, you can use the . By automatically handling out-of-sequence records, the APPLY CHANGES API in Delta Live Tables ensures correct processing of CDC records and removes the need to develop complex logic for handling out-of-sequence Jun 9, 2021 · Below, you can see how to use the changed data to determine which dates and stock symbols have changed. Dec 21, 2022 · What I've done so far can be summed up in two approaches. To create a single table with merged schema, you can use the following code:. 4 LTS version we have low shuffle merge, so merge is more faster. Once MERGE INTO. In this step all the data from source 1 flows perfectly through the stream but the data from source 2 doesn't. The COPY INTO SQL command lets you load data from a file location into a Delta table. col1 = source. sql Jan 25, 2023 · Matillion's low-code, visual ELT platform makes it easy for anyone to integrate data from any source into Databricks SQL Warehouse thus making analytics and AI data business-ready, and faster. Aug 5, 2022 · Spoke with a Databricks Solution Architect today, and he mentioned that I needed to use a ThreadPoolExecutor, which is something outside the Auto Loader or Databricks itself, but native to Python. from 10. Apr 23, 2024 · SQL. id bigint generated always as identity (START WITH 1 INCREMENT BY 1), name string. Read each matching file into memory, update the relevant rows, and write out the result into a new data file. -- Delete all target rows that have no matches in the source table. このページでは、 MERGE コマンドで正しい Oct 30, 2023 · Hi @Mohammad_Younus , When dealing with large Delta tables with over 200 million rows, optimizing merge operations becomes crucial to avoid memory overflow and reduce execution time. option ("partitionBy", "partition_key"). 0 (see corresponding PR1, PR2). See Low shuffle merge on Azure Jun 3, 2024 · Databricks SQL UI caching. Delta Live Tables simplifies change data capture (CDC) with the APPLY CHANGES API. So, suppose I have a table named table_1 and a cached view named cached_view_1. id, S. ON false // an artificial merge condition. Create and manage branches for development work, including merging, rebasing, and resolving conflicts. 1 and above. > SELECT * FROM person WHERE age > (SELECT avg(age) FROM person); 300 Mike 80 -- Correlated Subquery in `WHERE` clause. 复制. Your job is to create column 3, ‘ dttm ’, timestamp, formatting. This eliminates the need to manually track and apply schema changes over time. May 23, 2022 · Failed to merge incompatible data types LongType and StringType. Important. When inserting or manipulating rows in a table Databricks automatically dispatches rows into the appropriate partitions. sql ('MERGE INTO test t USING src s ON s. The merge into is used, and the merge works fine for 1 year. day = '12' and oldData. I'm trying to merge data to this on all three partition columns + an extra column (an ID). This includes the row data along with metadata indicating whether the specified row was inserted, deleted, or updated. To keep a Git folder in Databricks at the latest version, you can set up Git automation to call the Repos API. Databricks Delta Lake, the next-generation engine built on top of Apache Spark™, now supports the MERGE command, which allows you to efficiently upsert and delete records in your data lakes. Jun 1, 2023 · Learn how to use partition pruning to improve the performance of Delta Lake MERGE INTO queries. I used PySpark in Feb 27, 2023 · I have a delta table that is partitioned by Year, Date and month. sql(f'select * from {tables[0]}') #load 1st table to a dataframe #display(final_df) final = 'final_df' for table in tables[1:]: final = final + f'. Delta Lake MERGE statements. MERGE INTO demo dst USING ( SELECT DISTINCT <required columns>, "9" AS col9 FROM demo_raw WHERE <where clause> ) src ON src. Hi @Tássio Santos . Suppose you have a source table named Oct 22, 2020 · WHEN NOT MATCHED THEN. converting the two delta live tables into spark dataframes and then perform the merge () operation with them is the first and then create a new dlt. Delta Lake supports upserts using the merge operation. Sep 29, 2020 · Delta Lake performs an UPDATE on a table in two steps: Find and select the files containing data that match the predicate, and therefore need to be updated. The semantics for ignoreChanges differ greatly from skipChangeCommits. merge (upsert) does two passes on the source data. Similarly for other use case, we have requirement to merge and update existing records in delta table. While in the Databricks ecosystem it’s a lot easier to merge data from a Spark Structured Stream into a Delta Lake table & really easy to connect to and use, sometimes I’m still coming across projects, where the business users don’t want to abandon their Relational Database (such as SQL Server) just yet, so they want the data streamed to the database — or sometimes both to the May 10, 2022 · Cause. t3'] final_df = spark. I know that apply_changes function Merge into and data loss. But recently I begin notice some of data is deleted from merge into without delete specified. s Jun 25, 2021 · Options. But what about MERGE INTO function that we run in sql notebook of databricks. Id and s. Feb 3, 2022 · We are reading files using Autoloader in Databricks. Whether all nullability and check constraints are met. Whether the schema matches that of the table or if the schema needs to be evolved. 2) ‘ tm ’ string, as shown. Applies to: Databricks SQL Databricks Runtime 10. To use partitions, you define the set of partitioning column when you create a table by including the PARTITIONED BY clause. Aug 18, 2023 · All the resources I checked mentioned to perform Merge into operation but what happens is I have to overwrite the entire table and cannot just update/replace one record directly in Azure SQL table. fee = 40; merge vs MERGE INTO. 4 LTS and above. マージを使用して一致しない行をすべて変更する. For an example, let's say the existing table looks like this: Target (existing delta table) Nov 3, 2021 · if they are already written, you have to bite the apple and read them (with spark/databricks or ADF data flow). When creating new entries I would like to also create a unique uuid for that entry that I can use to crossreference with other tables. Another option is by using delta lake, using MERGE statement (incoming data is merged in the existing). > MERGE INTO target USING source ON target. 06-06-2022 05:39 AM. So if you DO care about the Spark metrics or logs in Arbitrary Stateful Aggregation inside mapGroupsWithState / flatmapGroupsWithState - do persist/cache before merge inside foreachBatch , otherwise sent metrics will have double (x2) values and logs aggregation logs will be emitted twice Apr 4, 2023 · Yes, using the Spark Synapse connector could be a good option for upserting data from a Delta table into a SQL Server table. If they don’t match, an exception is raised. MERGE INTO support for row-level concurrency requires Photon in Databricks Runtime 14. May 19, 2020 · Support for schema evolution in merge operations ( #170) - You can now automatically evolve the schema of the table with the merge operation. You can upsert data from a source table, view, or DataFrame into a target Delta table by using the MERGE SQL operation. Halloween Protection is much more efficient on MERGE. If not then you'll have to read another dataframe from Synapse, merge them in Spark/Databricks and then do an upsert. May 8, 2024 · Low Shuffle Merge is now enabled by default. I haven't tried but I suspect it will fail with the same message on INSERT because uc. Databricks SQL および Databricks Runtime 12. Prerequisites Valid access credentials to a DLP instance with adequate access permissions to perform the action in context. databricks. Liquid Clustering Internals: Jan 23, 2023 · If each table has unique columns, you can use unionByName. Delta Lake supports inserts, updates, and deletes in MERGE, and it supports extended syntax beyond the SQL standards to facilitate advanced use cases. You can also specify the partition directly using a PARTITION clause. > SELECT * FROM person AS parent WHERE EXISTS (SELECT 1 FROM person AS child WHERE parent. Apr 8, 2024 · MERGE INTO my_table AS target USING new_data AS source ON target. The Spark Synapse connector allows you to read and write data from Azure Synapse Analytics, formerly known as SQL Data Warehouse, and it supports both read and write operations. One way is to coalesce small files into larger ones. You can also increase this threshold by changing the following configuration: Sep 15, 2023 · Summary. testidentityfinal (. col0, source. The first thing to do is to save the table using the delta format to provide support for transactional capabilities and support for DELETE/UPDATE/MERGE operations with spark Access the Git Merge operation by selecting it from the kebab in the upper right of the Git operations dialog. 3 LTS and above, Photon is not required. Apr 18, 2024 · MERGE INTO. Source system is giving full snapshot of complete data in files. col0 = source. The Delta table at this version is called the initial snapshot. 2 and above, you can specify schema evolution in a merge statement using the following syntax: MERGE WITH SCHEMA EVOLUTION INTO target_table USING source ON source. date::DATE) < -30) s ON m. t2','default. WHEN NOT MATCHED BY SOURCE THEN. As shown below, you can use the changed data from the silver table to aggregate only the data on the rows that need to be updated or inserted into the gold table. I have a delta table with 20 M rows, Ther table is being updated dozens of times per day. MERGE dramatically simplifies how a number of common data Jul 17, 2023 · Step2: While inserting values into the table mention the column name under () for which you want to insert the values. Sep 25, 2023 · The new Git merge, Git rebase and conflict resolution features in Repos make collaboration more effective and seamless, further enhancing the developer experience. WHEN NOT MATCHED BY SOURCE THEN DELETE -- Multiple NOT MATCHED BY SOURCE clauses conditionally deleting unmatched target rows and updating two columns for all other matched rows. Applies to: Databricks SQL Databricks Runtime. . Jun 5, 2022 · I have a delta table with 20 M rows, Ther table is being updated dozens of times per day. Databricks recommends you avoid interacting directly with data and transaction log files in Delta Lake file directories to avoid corrupting your tables. Many tens of billions of records. A source table can be a subquery so the following should give you what you're after. D. Easily configurable file or directory filters from cloud storage, including S3, ADLS Gen2, ABFS, GCS, and Unity Catalog volumes. Sep 8, 2022 · 09-08-2022 03:41 AM. So we want to read the data and write in delta table in override mode so all old data is replaced by the new data. SELECT id, country_code, fullname_2, firstname_2. The configuration setting that was previously used to enable this feature has been removed. Per user caching of all query and legacy dashboard results results in the Databricks SQL UI. id = s. 適用対象: Databricks SQL Databricks Runtime. Only when you are writing the data in delta format, you can use this functionality. Name, S. This can happen if you have made changes to the nested column fields. . I. ); Step2: While inserting values into the table mention the column name under () for which you want to insert the values. My merge statement is below: MERGE INTO delta. Here are some effective strategies to enhance the efficiency of your merge operations: Utilize the MERGE Operation: The MERGE operation is the recommended method Feb 10, 2021 · I'm using a Databricks notebook to extract gz-zipped csv files and loading into a dataframe object. Merges a set of updates, insertions, and deletions based on a source table into a target Delta table. 2以前では、mergeに指定できるwhenMatchedは最大2つ、whenNotMatchedは最大1つとなります。 Nov 29, 2023 · I am trying to update a Databricks Delta table that already exists (the target) with an incoming json file (the source) with a MERGE INTO operation in Databricks. ソース テーブルに基づいて、更新、挿入、および削除のセットをターゲット Delta テーブルにマージします。. Jan 18, 2020 · DeltaTable. To do this, use INNER JOIN on the table_changes ('table_name','version') The Aug 11, 2023 · Saved some data inside. col1 WHEN MATCHED THEN UPDATE SET * EXCEPT (col9) WHEN NOT MATCHED THEN INSERT * EXCEPT (col9) May 14, 2024 · The following example shows how to create a Delta table and then use the COPY INTO SQL command to load sample data from Databricks datasets into the table. When i ran this command i have below error: It seems that we do not have NOT MATCHED BY SOURCE in spark! Follow these steps: Open the notebook where you want to write the merge query. This behavior improves the performance of the MERGE INTO command significantly for most workloads. 2. Mar 27, 2023 · Hi @andrew li Merge functionality is a part of Delta Lake API and not native dataframe API. Nov 17, 2023 · So far everything works fine. 3. Apr 21, 2023 · Options. Delta Lake uses data skipping whenever possible to speed up this process. id WHEN MATCHED THEN UPDATE SET m. The partition columns are not included in the ON condition, as they are already being used to filter the data. Jun 12, 2024 · In Databricks Runtime 15. option ("replaceWhere", "partition_key = 'partition_value'") method when creating the Delta table object for each partition. In Databricks Git folders, you can use Git functionality to: Clone, push to, and pull from a remote Git repository. dl_id is NULL for some rows and `whenNotMatchedInsertAll` will attempt to insert a value for dl_id field instead of generating one (as if it has been user provided). When enabled on a Delta table, the runtime records change events for all the data written into the table. id Upsert into a table using merge. Merge into onmly do updates. May 16, 2024 · For other Databricks Runtime versions, see Row-level concurrency preview behavior (legacy). id WHEN MATCHED THEN UPDATE SET * WHEN NOT MATCHED THEN INSERT * I get the error: Is there any way that I can merge two DataFrames? Should I convert them into Delta table first? Jan 25, 2023 · This kind of functionality is supported with the new WHEN NOT MATCHED BY SOURCE clause in the MERGE statement . In Databricks Runtime 15. col1); Remember to adjust the MERGE condition according to your specific use case. The delta table performs schema validation of every column, and the source dataframe column data types must match the column data types in the target table. key WHEN MATCHED THEN UPDATE SET * WHEN NOT MATCHED THEN INSERT * WHEN NOT MATCHED BY SOURCE THEN DELETE For other Databricks Runtime versions, see Row-level concurrency preview behavior (legacy). In the beginning we were loading data into the delta table by using the merge function as given below. year = '2023' and oldData. These validations include: Whether the data can be parsed. Dec 12, 2018 · You are given a two column dataframe: 1) ‘ dt ’, string, as shown. pdr_debit_card as TARGET USING (SELECT * FROM ( - 10794 WHEN NOT MATCHED BY TARGET support Databricks Runtime 12. MERGE INTO events. This feature is in Public Preview. With ignoreChanges enabled, rewritten data files in the source table are re-emitted after a data changing operation such as UPDATE, MERGE INTO, DELETE (within partitions), or OVERWRITE Dec 1, 2021 · One problem I recently ran into when building a large Data Lake on Databricks was the issue of populating new and updated records into massive Fact tables. You can also run the SQL code from a query associated with a SQL warehouse in Applies to: Databricks SQL Databricks Runtime 10. key = source. This incoming dataframe inc_df had data for all partitions. <path of delta table> oldData using df newData on oldData. Change data feed allows Databricks to track row-level changes between versions of a Delta table. Deleted) -- DELETE. Pick the lower cost. Use compaction. View solution You can configure Auto Loader to automatically detect the schema of loaded data, allowing you to initialize tables without explicitly declaring the data schema and evolve the table schema as new columns are introduced. -- Delete all target rows that have a match in the source table. 3 LTS and lower, ignoreChanges is the only supported option. In your Git provider, set up automation that, after every successful merge of a PR into the main branch, calls the Repos API endpoint on the appropriate Git folder to update it to the latest version. It was just released on Databricks as part of the Databricks Runtime 12. merge" function vs databricks Mar 13, 2023 · MERGE INTO delta. To upsert data, you can first read the data Sep 8, 2020 · Here are some thoughts: You'll be using spark cluster's compute in option 1 and Synapse' compute in option 2. See examples of queries with and without partition pruning, and how to specify the partition columns in the query. You can use the merge operation to merge data from your source into your target Delta table, and then use whenMatchedUpdate to update the id2 column to be equal to the id1 column in the source data. This is a common use case that we observe many of Databricks customers are leveraging Delta Lakes to perform, and keeping their data lakes up to date Apr 23, 2024 · SQL. Mar 6, 2021 · You can supply a proxy value for that column and then exclude it in the statement using EXCEPT clause. Jan 13, 2023 · I have a PySpark streaming pipeline which reads data from a Kafka topic, data undergoes thru various transformations and finally gets merged into a databricks delta table. A common use case that we run into at Databricks is that customers looking to perform change data capture (CDC) from one or many sources into a set of Databricks Delta tables. You can run the example Python, R, Scala, or SQL code from a notebook attached to an Azure Databricks cluster. 06-25-2021 09:22 AM. The merge function in Databricks Git folders merges one branch into another using git merge. Ready to get started? Try running a merge or rebase operation within Databricks or dive deeper into the Databricks Repos documentation to learn more. toPandas () Jun 12, 2024 · The merge strategy The merge incremental strategy requires: file_format: delta or hudi; Databricks Runtime 5. insert into default. This feature is available on Databricks Runtime 11. To elaborate: If you have this in DB: This is the dataframe (say df_new) you're trying to write to DB: Atomic transactions with Delta Lake provide many options for updating data and metadata. 0 and above comes with AQE (Adaptive Query Execution), which can also convert the sort-merge join into broadcast hash join (BHJ) when the runtime statistics of any join side is smaller than the adaptive broadcast hash join threshold, which is 30MB by default. This will acquire a lock on the partition and prevent other jobs from modifying it while the merge operation is in progress. This blog will show you how to create an ETL pipeline that loads a Slowly Changing Dimensions (SCD) Type 2 using Matillion into the Databricks Lakehouse Databricks - Merge Into Snap is a write-type Snap that inserts and updates data in a DLP instance. key WHEN MATCHED THEN UPDATE SET * WHEN NOT MATCHED THEN INSERT * WHEN NOT MATCHED BY SOURCE THEN DELETE Oct 6, 2017 · Spark does support MERGE operation using Delta Lake as storage format. autoMerge. See the following code. Id = t. key. Is there any performance difference when we use databrciks pyspark ". @Robert Pearce : It is possible to achieve the desired behavior using apply_changes in Databricks Delta Lake. 2 LTS 以降では、 WHEN NOT MATCHED BY SOURCE 句を使用して、ソース テーブル内に対応するレコードがないターゲット テーブル内のレコードを UPDATE または DELETE できます。 MERGE INTO warehouse. The MERGE INTO command now always uses the new low-shuffle implementation. Auto Loader can also “rescue” data that was The MERGE statement applies a standard $40 fee to members who joined the gym more than 30 days ago, after the free trial expired: MERGE INTO members m USING ( SELECT id, date FROM signup WHERE DATEDIFF(day, CURRENT_DATE(), signup. So it is necessary to identify all the cases where the merge can update the data, for this A query is made on the incremental data to generate a dictionary of this type: filter_columns = spark. “How the devil do I merge 35 million records from one Delta Lake table into another table that has 10’s of billions of records? And do this a few times Apr 25, 2022 · The MERGE INTO command in Delta Lake on Databricks enables customers to efficiently upsert and delete records in their data lakes – you can check out our previous deep dive on the topic here. SELECT * FROM person WHERE id BETWEEN 200 AND 300 ORDER BY id; 200 Mary NULL 300 Mike 80 -- Scalar Subquery in `WHERE` clause. Delta Lake is truly a wonderful tool for big data. Write the SQL-like merge query using the appropriate syntax. This page contains details for using the correct syntax with the MERGE command. For example, assume we have a column called Address with the fields streetName, houseNumber, and city nested inside. 3 LTS and above. Please check the below link to achieve Merge using delta lake API. This is useful in scenarios where you want to upsert change data into a table and the schema of the data changes over time. April 18, 2024. このステートメントは、Delta Lake テーブルでのみサポートされます。. Delta Lake supports inserts, updates and deletes in MERGE, and it supports extended syntax beyond the SQL standards to facilitate advanced use cases. 2 and above, you can specify schema evolution in a merge statement using the following syntax: MERGE WITH SCHEMA EVOLUTION INTO target_table USING source ON source . 2. Then you can coalesce/repartition them and write the merged files back to the data lake. In Databricks Runtime 14. clientid WHEN MATCHED THEN DELETE; In this example, the partition columns (year, month, day) are used in the subquery in the USING clause to filter the data being merged. The second option is to use CDC, but I am unsure on how to actually do this. col1 = dst. testidentityfinal (name) values ("Vinay") I have also attached the snapshots of the notebook of internal repro along with the output for your reference. Is there any way to update just one record at a time without overwriting the entire table? In Databricks Runtime 11. Feb 3, 2022 · Today I want to talk about a wonderful feature of Databricks + Delta Lake MERGE statements that are perfect for quietly and insidiously injecting duplicates into your Data Warehouse or Data Lake. UNION. When i filter on source_name = source2, i get the error: Keeping the source of the MERGE Oct 29, 2018 · Note: We also recommend you read Efficient Upserts into Data Lakes with Databricks Delta which explains the use of MERGE command to do efficient upserts and deletes. yo sa ov ua qf cn jh sy fy ki