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https://issues.apache.org/jira/browse/PHOENIX-6907?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17738844#comment-17738844
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ASF GitHub Bot commented on PHOENIX-6907:
-----------------------------------------
jpisaac commented on code in PR #1598:
URL: https://github.com/apache/phoenix/pull/1598#discussion_r1247322349
##########
phoenix-core/src/main/java/org/apache/phoenix/iterate/ExplainTable.java:
##########
@@ -111,8 +126,63 @@ private String explainSkipScan() {
return buf.toString();
}
- protected void explain(String prefix, List<String> planSteps,
- ExplainPlanAttributesBuilder explainPlanAttributesBuilder) {
+ /**
+ * Get regions that represent the given range of start and end key for the
given table, and
+ * all the regions to the regionLocations list.
+ *
+ * @param tableName the table name.
+ * @param startKey the start rowkey.
+ * @param endKey the end rowkey.
+ * @param includeEndKey true if end key needs to be included.
+ * @param reload true if reload from meta is necessary.
+ * @param regionBoundaries set of region boundaries to get the unique list
of region locations.
+ * @param regionLocations the list of region locations as output.
+ * @throws IOException if something goes wrong while creating connection
or querying region
+ * locations.
+ */
+ private void getRegionsInRange(final byte[] tableName,
+ final byte[] startKey,
+ final byte[] endKey,
+ final boolean includeEndKey,
+ final boolean reload,
+ Set<RegionBoundary> regionBoundaries,
+ List<HRegionLocation> regionLocations)
+ throws IOException, SQLException {
+ final boolean endKeyIsEndOfTable = Bytes.equals(endKey,
HConstants.EMPTY_END_ROW);
+ if ((Bytes.compareTo(startKey, endKey) > 0) && !endKeyIsEndOfTable) {
+ throw new IllegalArgumentException(
+ "Invalid range: " + Bytes.toStringBinary(startKey) + " > "
+
+ Bytes.toStringBinary(endKey));
+ }
+ byte[] currentKey = startKey;
+ try (Table table =
context.getConnection().getQueryServices().getTable(tableName)) {
+ do {
+ HRegionLocation regionLocation =
+ table.getRegionLocator().getRegionLocation(currentKey,
reload);
+ RegionBoundary regionBoundary =
+ new
RegionBoundary(regionLocation.getRegion().getStartKey(),
+ regionLocation.getRegion().getEndKey());
+ if (!regionBoundaries.contains(regionBoundary)) {
+ regionLocations.add(regionLocation);
+ regionBoundaries.add(regionBoundary);
+ }
+ currentKey = regionLocation.getRegion().getEndKey();
+ // condition1 = currentKey != END_ROW_KEY
+ // condition2 = endKeyIsEndOfTable == true
+ // condition3 = currentKey < endKey
+ // condition4 = includeEndKey == true
+ // condition5 = currentKey == endKey
+ // while (condition1 && (condition2 || condition3 ||
(condition4 && condition5)))
Review Comment:
nit: Might be easier on the reader if it is in plain layman's language
> Explain Plan should output region locations with servers
> --------------------------------------------------------
>
> Key: PHOENIX-6907
> URL: https://issues.apache.org/jira/browse/PHOENIX-6907
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Viraj Jasani
> Assignee: Viraj Jasani
> Priority: Major
> Fix For: 5.2.0, 5.1.4
>
>
> As of today, explain plan provides details related to scan key range size,
> size of the scan lists (for parallel scans), hints, client/server sorted by,
> order by, server filter etc. It provides as much close details to the
> physical plans as possible.
> If we could also make explain plan output to include region locations that
> also contains regionserver details on which the region is currently residing,
> this might turn out to be really good insights. For full table scans, this
> also means that we would end up including very higher number of region
> locations and it would not be ideal to print all of them in the output. We
> can enforce a limit on the num of region locations to print (default value
> could be 10 or so). For point lookup and range scans, we can find the region
> locations with regionserver as quite useful for the real time analysis of
> slowness experienced by the given query.
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