From b486c5ce2f342f4ec659b31764320d740ab40f46 Mon Sep 17 00:00:00 2001
From: Keith Bostic <keith.bostic@mongodb.com>
Date: Fri, 21 Oct 2016 23:10:39 -0400
Subject: WT-2880 Add Zstandard compression support (#3075)

* Fix a bug found by inspection in LZ4 code: we're going to offset the destination buffer by sizeof(LZ4_PREFIX), so we need to offset the destination buffer length by the same amount.

* Prettiness pass through the snappy driver so it and the zstd driver look the same, minor cleanup in zlib.

* Add the compression_level configuration option to the zstd extension initialization function so it's possible to set the compression level from an application.

* Fix a bug in zlib raw compression: the destination buffer size (dst_len), can be smaller than the target page size (page_max), use the smaller of the two values to set the target compression size.

* The zlib raw compression function could return without calling deflateEnd on its z_stream structures, potentially leaking memory and scratch buffers.

* If the default reserved bytes for zlib raw compression isn't sufficient, we fail on compression of what might be very large blocks. We don't have information on how many bytes need to be reserved in order to know the final deflate() will succeed, and the default value was experimentally derived, for all we know there are workloads where the default will fail
a lot. Add a fallback before failing hard, try with 2x the default reserved space.
---
 examples/java/com/wiredtiger/examples/ex_all.java | 29 +++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'examples/java/com/wiredtiger')

diff --git a/examples/java/com/wiredtiger/examples/ex_all.java b/examples/java/com/wiredtiger/examples/ex_all.java
index 83a37e9a6a5..cf8491aa4f8 100644
--- a/examples/java/com/wiredtiger/examples/ex_all.java
+++ b/examples/java/com/wiredtiger/examples/ex_all.java
@@ -549,6 +549,12 @@ session_ops(Session session)
         "block_compressor=zlib,key_format=S,value_format=S");
     /*! [Create a zlib compressed table] */
     ret = session.drop("table:mytable", null);
+
+    /*! [Create a zstd compressed table] */
+    ret = session.create("table:mytable",
+        "block_compressor=zstd,key_format=S,value_format=S");
+    /*! [Create a zstd compressed table] */
+    ret = session.drop("table:mytable", null);
     } // if (false)
 
     /*! [Configure checksums to uncompressed] */
@@ -942,6 +948,29 @@ allExample()
     /*! [Configure zlib extension] */
     conn.close(null);
 
+    /*! [Configure zlib extension with compression level] */
+    conn = wiredtiger.open(home,
+        "create," +
+        "extensions=[/usr/local/lib/" +
+	"libwiredtiger_zlib.so=[config=[compression_level=3]]]");
+    /*! [Configure zlib extension with compression level] */
+    conn.close(null);
+
+    /*! [Configure zstd extension] */
+    conn = wiredtiger.open(home,
+        "create," +
+        "extensions=[/usr/local/lib/libwiredtiger_zstd.so]");
+    /*! [Configure zstd extension] */
+    conn.close(null);
+
+    /*! [Configure zstd extension with compression level] */
+    conn = wiredtiger.open(home,
+        "create," +
+        "extensions=[/usr/local/lib/" +
+	"libwiredtiger_zstd.so=[config=[compression_level=9]]]");
+    /*! [Configure zstd extension with compression level] */
+    conn.close(null);
+
     /*
      * This example code gets run, and direct I/O might not be available,
      * causing the open to fail.  The documentation requires code snippets,
-- 
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