On 2017/06/23 10:22, Masahiko Sawada wrote:
> On Thu, Jun 22, 2017 at 6:55 PM, Amit Langote
> <[email protected]> wrote:
>> On 2017/06/22 16:56, Michael Paquier wrote:
>>> Did you check this patch with wal_consistency_checking? I am getting
>>> failures so your patch does not have the masking of GIN pages
>>> completely right:
>>> FATAL: inconsistent page found, rel 1663/16385/28133, forknum 0, blkno 0
>>> CONTEXT: WAL redo at 0/39379EB8 for Gin/UPDATE_META_PAGE:
>>> That's easily reproducible with installcheck and a standby replaying
>>> the changes. I did not look at the code in details to see what you may
>>> be missing here.
>>
>> Oh, wasn't sure about the gin_mask() changes myself. Thanks for checking.
>>
>> Actually, the WAL consistency check fails even without patching
>> gin_mask(), so the problem may be with the main patch itself. That is,
>> the patch needs to do something else other than just teaching
>> GinInitMetabuffer() to initialize pd_lower. Will look into that.
>>
>
> I've not read the code deeply but I guess we should use
> GinInitMetabuffer() in ginRedoUpdateMetapage() instead of
> GinInitPage(). Maybe also GinInitPage() in ginRedoDeleteListPages() is
> the same.
That was it, thanks for the pointer.
Attached updated patch, which I confirmed, passes wal_consistency_check = gin.
Thanks,
Amit
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index 91e4a8cf70..52de599b29 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -372,6 +372,13 @@ GinInitMetabuffer(Buffer b)
metadata->nDataPages = 0;
metadata->nEntries = 0;
metadata->ginVersion = GIN_CURRENT_VERSION;
+
+ /*
+ * Set pd_lower just past the end of the metadata. This is not
essential
+ * but it makes the page look compressible to xlog.c.
+ */
+ ((PageHeader) page)->pd_lower =
+ ((char *) metadata + sizeof(GinMetaPageData)) - (char
*) page;
}
/*
diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index 7ba04e324f..6d2e528852 100644
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -514,7 +514,7 @@ ginRedoUpdateMetapage(XLogReaderState *record)
Assert(BufferGetBlockNumber(metabuffer) == GIN_METAPAGE_BLKNO);
metapage = BufferGetPage(metabuffer);
- GinInitPage(metapage, GIN_META, BufferGetPageSize(metabuffer));
+ GinInitMetabuffer(metabuffer);
memcpy(GinPageGetMeta(metapage), &data->metadata,
sizeof(GinMetaPageData));
PageSetLSN(metapage, lsn);
MarkBufferDirty(metabuffer);
@@ -656,7 +656,7 @@ ginRedoDeleteListPages(XLogReaderState *record)
Assert(BufferGetBlockNumber(metabuffer) == GIN_METAPAGE_BLKNO);
metapage = BufferGetPage(metabuffer);
- GinInitPage(metapage, GIN_META, BufferGetPageSize(metabuffer));
+ GinInitMetabuffer(metabuffer);
memcpy(GinPageGetMeta(metapage), &data->metadata,
sizeof(GinMetaPageData));
PageSetLSN(metapage, lsn);
@@ -776,18 +776,11 @@ gin_mask(char *pagedata, BlockNumber blkno)
mask_page_hint_bits(page);
/*
- * GIN metapage doesn't use pd_lower/pd_upper. Other page types do.
Hence,
- * we need to apply masking for those pages.
+ * For GIN_DELETED page, the page is initialized to empty. Hence, mask
+ * the page content.
*/
- if (opaque->flags != GIN_META)
- {
- /*
- * For GIN_DELETED page, the page is initialized to empty.
Hence, mask
- * the page content.
- */
- if (opaque->flags & GIN_DELETED)
- mask_page_content(page);
- else
- mask_unused_space(page);
- }
+ if (opaque->flags & GIN_DELETED)
+ mask_page_content(page);
+ else
+ mask_unused_space(page);
}
--
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