Commita6370fd

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Ensure that XLOG_HEAP2_VISIBLE always targets an initialized page.

Andres Freund

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Original file line number	Diff line number	Diff line change
`@@ -663,6 +663,24 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,`
`663`	`663`	`/* empty pages are always all-visible */`
`664`	`664`	`if (!PageIsAllVisible(page))`
`665`	`665`	`{`
	`666`	`+/*`
	`667`	`+ * It's possible that another backend has extended the heap,`
	`668`	`+ * initialized the page, and then failed to WAL-log the page`
	`669`	`+ * due to an ERROR. Since heap extension is not WAL-logged,`
	`670`	`+ * recovery might try to replay our record setting the`
	`671`	`+ * page all-visible and find that the page isn't initialized,`
	`672`	`+ * which will cause a PANIC. To prevent that, check whether`
	`673`	`+ * the page has been previously WAL-logged, and if not, do that`
	`674`	`+ * now.`
	`675`	`+ *`
	`676`	`+ * XXX: It would be nice to use a logging method supporting`
	`677`	`+ * standard buffers here since log_newpage_buffer() will write`
	`678`	`+ * the full block instead of omitting the hole.`
	`679`	`+ */`
	`680`	`+if (RelationNeedsWAL(onerel)&&`
	`681`	`+PageGetLSN(page)==InvalidXLogRecPtr)`
	`682`	`+log_newpage_buffer(buf);`
	`683`	`+`
`666`	`684`	`PageSetAllVisible(page);`
`667`	`685`	`MarkBufferDirty(buf);`
`668`	`686`	`visibilitymap_set(onerel,blkno,buf,InvalidXLogRecPtr,`

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