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https://issues.apache.org/jira/browse/PHOENIX-4594?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16619722#comment-16619722
]
ASF GitHub Bot commented on PHOENIX-4594:
-----------------------------------------
Github user karanmehta93 commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/347#discussion_r218595912
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/iterate/BaseResultIterators.java
---
@@ -972,32 +977,84 @@ private static boolean clipKeyRangeBytes(RowKeySchema
schema, int fieldIndex, in
decoder = new PrefixByteDecoder(gps.getMaxLength());
firstRegionStartKey = new
ImmutableBytesWritable(regionLocations.get(regionIndex).getRegionInfo().getStartKey());
try {
- int c;
- // Continue walking guideposts until we get past the
currentKey
- while ((c=currentKey.compareTo(currentGuidePost =
PrefixByteCodec.decode(decoder, input))) >= 0) {
- // Detect if we found a guidepost that might be in
the first region. This
- // is for the case where the start key may be past
the only guidepost in
- // the first region.
- if (!gpsForFirstRegion &&
firstRegionStartKey.compareTo(currentGuidePost) <= 0) {
- gpsForFirstRegion = true;
+ if (firstRegionStartKey.getLength() > 0 &&
this.gpsMovingWindowSize > 0) {
+ // Continuously decode and load guide posts in
batches (moving window). For each moving window,
+ // firstly compare the searching key with the last
element to see whether the searching key is
+ // in the current window. If it isn't, perform
binary search in the window; otherwise, move to
--- End diff --
nit: `If it is`
> Perform binary search on guideposts during query compilation
> ------------------------------------------------------------
>
> Key: PHOENIX-4594
> URL: https://issues.apache.org/jira/browse/PHOENIX-4594
> Project: Phoenix
> Issue Type: Improvement
> Reporter: James Taylor
> Assignee: Bin Shi
> Priority: Major
> Attachments: PHOENIX-4594-0913.patch, PHOENIX-4594_0917.patch,
> PHOENIX-4594_0918.patch
>
>
> If there are many guideposts, performance will suffer during query
> compilation because we do a linear search of the guideposts to find the
> intersection with the scan ranges. Instead, in
> BaseResultIterators.getParallelScans() we should populate an array of
> guideposts and perform a binary search.
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