apache-drill

问题 i want use apache drill to do a page search. But it just provide a limit key words,I don't know how to write a good sql.Do any anybody can help me?Thank you! 回答1: Drill supports both LIMIT and OFFSET operators. So, pagination can be achieved using these. Sample query: SELECT * FROM cp.`employee.json` order by employee_id LIMIT 20 OFFSET 10 ROWS Some important ponits from Drill docs: The OFFSET number must be a positive integer and cannot be larger than the number of rows in the underlying

问题 I'm trying to make storage plugin for Hadoop (hdfs) and Apache Drill. Actually I'm confused and I don't know what to set as port for hdfs:// connection, and what to set for location. This is my plugin: { "type": "file", "enabled": true, "connection": "hdfs://localhost:54310", "workspaces": { "root": { "location": "/", "writable": false, "defaultInputFormat": null }, "tmp": { "location": "/tmp", "writable": true, "defaultInputFormat": null } }, "formats": { "psv": { "type": "text", "extensions

问题 I want to create storage plugin in drill for oracle jdbc. I copy ojdbc7.jar to apache-drill-1.3.0/jars/3rdparty path and add drill.exec.sys.store.provider.local.path = "/mypath" to dill.override.conf . when I want to create a new storage plugin with below configuration: { "type": "jdbc", "enabled": true, "driver": "oracle.jdbc.OracleDriver", "url":"jdbc:oracle:thin:user/pass@x.x.x.x:1521/orcll" } I get unable to create/update storage error. I am using Redhat 7 & Drill version - 1.3. in

问题 I am running SQL on MongoDB backend using Drill. I am getting response time ~500ms. But most of that time is spent on "First start" phase. Actual processing in drill is taking much less time(~50ms). Why does "First start" take so much time? I would like to know what drill in doing in that phase and if possible optimise that. Fragment profile Operator profile 回答1: After the first query Drill creates a lot of cache objects to improve the further work, see Generated Code Cache [1], [2], [3] for

问题 With help from the documentation : http://drill.apache.org/docs/rdbms-storage-plugin/ I've been trying to create a storage plugin for Mysql in Apache Drill, I tried multiple jdbc drivers : mysql-connector-java-5.1.39-bin , sqlserverjdbc but I always get the error: Please retry: error (unable to create/update storage) my configuration is as follows : { "type":"jdbc", "driver":"mysql-connector-java-5.1.39-bin", "url":"jdbc:mysql://localhost:3306", "username":"root", "password":"password",

问题 I am looking to convert HL7 v2 (older EDI format) messages to JSON, so I could make them processable under Apache Drill and compressible under Parquet. I looked into HAPI, but I am not having luck finding utility for non-XML HL7 to JSON conversion. Does anyone have a suggestion or a reference to a library? 回答1: Just use HAPI to convert to XML. The code below requires Saxon, because the XML-to-JSON requires XSLT 2.0, but if you already have a method to convert XML to JSON, then you just need

问题 what are the limitations of Apache Drill? where it fails when compared to Apache hive/impala? 回答1: My view on drill holistically, One of the main advantage of Apache drill is you can query across multiple databases. You just need to configure the sources & directly query them. Thats the biggest advantage of Apache drill. It was proved that its a best query among many other technologies.(check reference 2) I cannot call it as limitations but since its a query engine like it just takes the sql

问题 I'm using the text/tsv storage plugin with Apache drill and the output tsv files have ? for unicode characters. If I use the JSON storage plugin, the unicode is fine. Something like: URL: http://localhost:8047/query.json Payload: { "queryType":"SQL", "query": "CREATE TABLE st.`repo`.`test` AS SELECT * FROM st.`repo`.`unicode_data`" } 回答1: Set the JVM file encoding and this is fixed. JAVA_TOOL_OPTIONS=-Dfile.encoding=UTF8 来源： https://stackoverflow.com/questions/43151313/apache-drill-losing

问题 There are two JDBC drivers for apache-drill: drill-jdbc & drill-jdbc-all Maven dependencies: <dependency> <groupId>org.apache.drill.exec</groupId> <artifactId>drill-jdbc</artifactId> <version>1.4.0</version> </dependency> and <dependency> <groupId>org.apache.drill.exec</groupId> <artifactId>drill-jdbc-all</artifactId> <version>1.4.0</version> </dependency> I am using drill-jdbc and things are working fine. But according to drill's documentation for JDBC, driver is located at: <drill

问题 We have generated a parquet file in Dask (Python) and with Drill (R using the Sergeant packet ). We have noticed a few issues: The format of the Dask (i.e. fastparquet ) has a _metadata and a _common_metadata files while the parquet file in R \ Drill does not have these files and have parquet.crc files instead (which can be deleted). what is the difference between these parquet implementations? 回答1: (only answering to 1), please post separate questions to make it easier to answer) _metadata