On Mon, 25 Jan 2021 21:25:54 GMT, Chris Plummer <[email protected]> wrote:
>> Lin Zang has updated the pull request incrementally with one additional
>> commit since the last revision:
>>
>> fix coding style issue
>
> test/hotspot/jtreg/serviceability/sa/ClhsdbDumpheap.java line 73:
>
>> 71: File out = new File(deCompressedFile);
>> 72: try {
>> 73: GZIPInputStream gis = new GZIPInputStream(new
>> FileInputStream(dump));
>
> `printStackTraces()` uses `Reader.getStack()`, which does not know about
> gzipped hprof files. However, `Reader.readFile()` was modified to
> automatically detect gzipped hprof files. I suggest you do the same for
> `getStack()` rather than making the test do all the work. Probably
> `getStack()` and `readFile()` can share the code that does this.
Hi Chris,
Thanks for review and nice catch on this.
I have considered using Reader.readFile() but it can not parse the gziped heap
dump successfully, and I investigated the reason is that the underlying
GzipAccess class requires the gziped heap dump file to have "HPROF
BLOCKSIZE=xxx" bytes in the gziped file header.
I also investigated that the implementation of jmap command in jdk.jcmd added
these words as a "comment section" in gz file headers, by passing it to the
"ZIP_GZip_Fully()" when it is first called.
But I cannot find a way to do same thing in GZIPOutputStream(), it's
writeHeader() does not support "comment" section.
Also I have verified the gziped heap dump file generated with
GZIPOutputStream() could be parsed by heaphero.io successfully.
So it seems to me that "HPROF BLOCKSIZE" may not be a must for general gziped
heap dump, but I am not sure whether it is required for testing the jmap
command, so I didn't touch GzipAccess in test and do decompress manually in
ClhsdbDumpheap.java.
I am considering another way to modify GzipAccess for testing to accept heap
dump file without "HPROF BLOCKSIZE" header, I will try to investigate whether
it could work.
What do you think?
Thanks!
Lin
-------------
PR: https://git.openjdk.java.net/jdk/pull/1712
