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https://issues.apache.org/jira/browse/DRILL-1394?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14267261#comment-14267261
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Jacques Nadeau commented on DRILL-1394:
---------------------------------------
One important note: schema change internally can be caused by a change in a
types or simply a creation of a new vector of the same type. This could also
happen if we were spuriously recreating the vector of the same type for some
reason. This may have been resolved by some of [~hgunes]'s recent changes with
regards to added and replacing vectors.
> COUNT(*) with UNION subquery returns two rows
> ---------------------------------------------
>
> Key: DRILL-1394
> URL: https://issues.apache.org/jira/browse/DRILL-1394
> Project: Apache Drill
> Issue Type: Bug
> Components: Query Planning & Optimization
> Affects Versions: 0.5.0
> Reporter: Bob Rumsby
> Assignee: Sean Hsuan-Yi Chu
> Priority: Critical
> Fix For: 0.8.0
>
>
> The following COUNT(*) query with a UNION subquery returns two rows, one
> count for each side of the union. Run by itself, the subquery returns 70000
> rows.
> 0: jdbc:drill:> select count(*) from (select trans_id from
> `clicks/clicks.campaign.json` union all select trans_id from
> `clicks/clicks.json`);
> +------------+
> | EXPR$0 |
> +------------+
> | 40000 |
> | 30000 |
> +------------+
> 2 rows selected (5.896 seconds)
> 0: jdbc:drill:> explain plan for select count(*) from (select trans_id from
> `clicks/clicks.campaign.json` union all select trans_id from
> `clicks/clicks.json`);
> +------------+------------+
> | text | json |
> +------------+------------+
> | 00-00 Screen
> 00-01 StreamAgg(group=[{}], EXPR$0=[COUNT()])
> 00-02 Project($f0=[0])
> 00-03 UnionAll(all=[true])
> 00-05 Project(trans_id=[$1])
> 00-07 Scan(groupscan=[EasyGroupScan
> [selectionRoot=/mapr/demorig/data/nested/clicks/clicks.campaign.json, columns
> = null]])
> 00-04 Project(trans_id=[$1])
> 00-06 Scan(groupscan=[EasyGroupScan
> [selectionRoot=/mapr/demorig/data/nested/clicks/clicks.json, columns = null]])
> | {
> "head" : {
> "version" : 1,
> "generator" : {
> "type" : "ExplainHandler",
> "info" : ""
> },
> "type" : "APACHE_DRILL_PHYSICAL",
> "options" : [ ],
> "queue" : 0,
> "resultMode" : "EXEC"
> },
> "graph" : [ {
> "pop" : "fs-scan",
> "@id" : 7,
> "files" : [
> "maprfs:/mapr/demorig/data/nested/clicks/clicks.campaign.json" ],
> "storage" : {
> "type" : "file",
> "enabled" : true,
> "connection" : "maprfs:///",
> "workspaces" : {
> "root" : {
> "location" : "/mapr/demorig/data",
> "writable" : false,
> "storageformat" : null
> },
> "nested" : {
> "location" : "/mapr/demorig/data/nested",
> "writable" : true,
> "storageformat" : "parquet"
> },
> "flat" : {
> "location" : "/mapr/demorig/data/flat",
> "writable" : true,
> "storageformat" : "parquet"
> },
> "views" : {
> "location" : "/mapr/demorig/data/views",
> "writable" : true,
> "storageformat" : "parquet"
> },
> "yelp" : {
> "location" : "/mapr/demorig/data/yelp",
> "writable" : true,
> "storageformat" : "json"
> }
> },
> "formats" : {
> "psv" : {
> "type" : "text",
> "extensions" : [ "tbl" ],
> "delimiter" : "|"
> },
> "csv" : {
> "type" : "text",
> "extensions" : [ "csv" ],
> "delimiter" : ","
> },
> "tsv" : {
> "type" : "text",
> "extensions" : [ "tsv" ],
> "delimiter" : "\t"
> },
> "parquet" : {
> "type" : "parquet"
> },
> "json" : {
> "type" : "json"
> }
> }
> },
> "format" : {
> "type" : "json"
> },
> "selectionRoot" : "/mapr/demorig/data/nested/clicks/clicks.campaign.json",
> "cost" : 7876.0
> }, {
> "pop" : "project",
> "@id" : 5,
> "exprs" : [ {
> "ref" : "`trans_id`",
> "expr" : "`trans_id`"
> } ],
> "child" : 7,
> "initialAllocation" : 1000000,
> "maxAllocation" : 10000000000,
> "cost" : 7876.0
> }, {
> "pop" : "fs-scan",
> "@id" : 6,
> "files" : [ "maprfs:/mapr/demorig/data/nested/clicks/clicks.json" ],
> "storage" : {
> "type" : "file",
> "enabled" : true,
> "connection" : "maprfs:///",
> "workspaces" : {
> "root" : {
> "location" : "/mapr/demorig/data",
> "writable" : false,
> "storageformat" : null
> },
> "nested" : {
> "location" : "/mapr/demorig/data/nested",
> "writable" : true,
> "storageformat" : "parquet"
> },
> "flat" : {
> "location" : "/mapr/demorig/data/flat",
> "writable" : true,
> "storageformat" : "parquet"
> },
> "views" : {
> "location" : "/mapr/demorig/data/views",
> "writable" : true,
> "storageformat" : "parquet"
> },
> "yelp" : {
> "location" : "/mapr/demorig/data/yelp",
> "writable" : true,
> "storageformat" : "json"
> }
> },
> "formats" : {
> "psv" : {
> "type" : "text",
> "extensions" : [ "tbl" ],
> "delimiter" : "|"
> },
> "csv" : {
> "type" : "text",
> "extensions" : [ "csv" ],
> "delimiter" : ","
> },
> "tsv" : {
> "type" : "text",
> "extensions" : [ "tsv" ],
> "delimiter" : "\t"
> },
> "parquet" : {
> "type" : "parquet"
> },
> "json" : {
> "type" : "json"
> }
> }
> },
> "format" : {
> "type" : "json"
> },
> "selectionRoot" : "/mapr/demorig/data/nested/clicks/clicks.json",
> "cost" : 5097.0
> }, {
> "pop" : "project",
> "@id" : 4,
> "exprs" : [ {
> "ref" : "`trans_id`",
> "expr" : "`trans_id`"
> } ],
> "child" : 6,
> "initialAllocation" : 1000000,
> "maxAllocation" : 10000000000,
> "cost" : 5097.0
> }, {
> "pop" : "union-all",
> "@id" : 3,
> "children" : [ 5, 4 ],
> "initialAllocation" : 1000000,
> "maxAllocation" : 10000000000,
> "cost" : 12973.0
> }, {
> "pop" : "project",
> "@id" : 2,
> "exprs" : [ {
> "ref" : "`$f0`",
> "expr" : "0"
> } ],
> "child" : 3,
> "initialAllocation" : 1000000,
> "maxAllocation" : 10000000000,
> "cost" : 12973.0
> }, {
> "pop" : "streaming-aggregate",
> "@id" : 1,
> "child" : 2,
> "keys" : [ ],
> "exprs" : [ {
> "ref" : "`EXPR$0`",
> "expr" : "count(1) "
> } ],
> "initialAllocation" : 1000000,
> "maxAllocation" : 10000000000,
> "cost" : 1.0
> }, {
> "pop" : "screen",
> "@id" : 0,
> "child" : 1,
> "initialAllocation" : 1000000,
> "maxAllocation" : 10000000000,
> "cost" : 1297.3
> } ]
> } |
> +------------+------------+
> 1 row selected (0.142 seconds)
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