[lucene-solr] branch master updated: LUCENE-9816: lazy-init LZ4-HC hashtable in BlockTreeTermsWriter

[rm...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

rmuir pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/lucene-solr.git


The following commit(s) were added to refs/heads/master by this push:
     new dade99c  LUCENE-9816: lazy-init LZ4-HC hashtable in BlockTreeTermsWriter
dade99c is described below

commit dade99cb4d70a8d1fd9eecd85741668828f7b874
Author: Robert Muir <rm...@apache.org>
AuthorDate: Sun Feb 28 17:54:30 2021 -0500

    LUCENE-9816: lazy-init LZ4-HC hashtable in BlockTreeTermsWriter
    
    LZ4-HC hashtable is heavy (128kb int[] + 128kb short[]) and must be
    filled with special values on initialization. This is a lot of overhead
    for fields that might not use the compression at all.
    
    Don't initialize this for a field until we see hints that the data might
    be compressible and need to use the table in order to test it out.
---
 .../codecs/lucene90/blocktree/Lucene90BlockTreeTermsWriter.java     | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene90/blocktree/Lucene90BlockTreeTermsWriter.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene90/blocktree/Lucene90BlockTreeTermsWriter.java
index 11a02e3..3908992 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene90/blocktree/Lucene90BlockTreeTermsWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene90/blocktree/Lucene90BlockTreeTermsWriter.java
@@ -917,6 +917,9 @@ public final class Lucene90BlockTreeTermsWriter extends FieldsConsumer {
         // it out if the
         // average suffix length is greater than 6.
         if (suffixWriter.length() > 6L * numEntries) {
+          if (compressionHashTable == null) {
+            compressionHashTable = new LZ4.HighCompressionHashTable();
+          }
           LZ4.compress(
               suffixWriter.bytes(), 0, suffixWriter.length(), spareWriter, compressionHashTable);
           if (spareWriter.size() < suffixWriter.length() - (suffixWriter.length() >>> 2)) {
@@ -1139,8 +1142,7 @@ public final class Lucene90BlockTreeTermsWriter extends FieldsConsumer {
     private final ByteBuffersDataOutput metaWriter = ByteBuffersDataOutput.newResettableInstance();
     private final ByteBuffersDataOutput spareWriter = ByteBuffersDataOutput.newResettableInstance();
     private byte[] spareBytes = BytesRef.EMPTY_BYTES;
-    private final LZ4.HighCompressionHashTable compressionHashTable =
-        new LZ4.HighCompressionHashTable();
+    private LZ4.HighCompressionHashTable compressionHashTable;
   }
 
   private boolean closed;