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ASF GitHub Bot commented on HAWQ-927: ------------------------------------- Github user kavinderd commented on a diff in the pull request: https://github.com/apache/incubator-hawq/pull/796#discussion_r71559534 --- Diff: src/backend/access/external/pxfheaders.c --- @@ -158,6 +166,29 @@ static void add_tuple_desc_httpheader(CHURL_HEADERS headers, Relation rel) pfree(formatter.data); } +static void add_projection_desc_httpheader(CHURL_HEADERS headers, ProjectionInfo *projInfo) { + int i; + char long_number[sizeof(int32) * 8]; + int *varNumbers = projInfo->pi_varNumbers; + StringInfoData formatter; + initStringInfo(&formatter); + + /* Convert the number of projection columns to a string */ + pg_ltoa(list_length(projInfo->pi_targetlist), long_number); + churl_headers_append(headers, "X-GP-ATTRS-PROJ", long_number); + + for(i = 0; i < list_length(projInfo->pi_targetlist); i++) { --- End diff -- Yes it will be in another PR related to [this](https://issues.apache.org/jira/browse/HAWQ-583?jql=project%20%3D%20HAWQ%20AND%20resolution%20%3D%20Unresolved%20AND%20assignee%20%3D%20kavinderd%20ORDER%20BY%20priority%20DESC) Jira. > Send Projection Info Data from HAWQ to PXF > ------------------------------------------ > > Key: HAWQ-927 > URL: https://issues.apache.org/jira/browse/HAWQ-927 > Project: Apache HAWQ > Issue Type: Sub-task > Components: External Tables, PXF > Reporter: Kavinder Dhaliwal > Assignee: Kavinder Dhaliwal > Fix For: backlog > > > To achieve column projection at the level of PXF or the underlying readers we > need to first send this data as a Header/Param to PXF. Currently, PXF has no > knowledge whether a query requires all columns or a subset of columns. -- This message was sent by Atlassian JIRA (v6.3.4#6332)