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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2012-11-30 17:02:29 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2012-11-30 17:03:31 -0500 |
| commit | d54a94b806825a119be86d5f73232b06dd9e9a16 (patch) | |
| tree | 96ce647864a22dd34458821167a676ff78663859 | |
| parent | b86327c1c53aab732e21666e8c8a97b11cded804 (diff) | |
| download | postgresql-d54a94b806825a119be86d5f73232b06dd9e9a16.tar.gz postgresql-d54a94b806825a119be86d5f73232b06dd9e9a16.zip | |
Take buffer lock while inspecting btree index pages in contrib/pageinspect.
It's not safe to examine a shared buffer without any lock.
| -rw-r--r-- | contrib/pageinspect/btreefuncs.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/contrib/pageinspect/btreefuncs.c b/contrib/pageinspect/btreefuncs.c index dbb2158ba8d..bc34af9b3c7 100644 --- a/contrib/pageinspect/btreefuncs.c +++ b/contrib/pageinspect/btreefuncs.c @@ -156,9 +156,9 @@ GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat *stat) } /* ----------------------------------------------- - * bt_page() + * bt_page_stats() * - * Usage: SELECT * FROM bt_page('t1_pkey', 1); + * Usage: SELECT * FROM bt_page_stats('t1_pkey', 1); * ----------------------------------------------- */ Datum @@ -204,6 +204,7 @@ bt_page_stats(PG_FUNCTION_ARGS) CHECK_RELATION_BLOCK_RANGE(rel, blkno); buffer = ReadBuffer(rel, blkno); + LockBuffer(buffer, BUFFER_LOCK_SHARE); /* keep compiler quiet */ stat.btpo_prev = stat.btpo_next = InvalidBlockNumber; @@ -211,6 +212,9 @@ bt_page_stats(PG_FUNCTION_ARGS) GetBTPageStatistics(blkno, buffer, &stat); + UnlockReleaseBuffer(buffer); + relation_close(rel, AccessShareLock); + /* Build a tuple descriptor for our result type */ if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE) elog(ERROR, "return type must be a row type"); @@ -247,10 +251,6 @@ bt_page_stats(PG_FUNCTION_ARGS) result = HeapTupleGetDatum(tuple); - ReleaseBuffer(buffer); - - relation_close(rel, AccessShareLock); - PG_RETURN_DATUM(result); } @@ -322,6 +322,7 @@ bt_page_items(PG_FUNCTION_ARGS) CHECK_RELATION_BLOCK_RANGE(rel, blkno); buffer = ReadBuffer(rel, blkno); + LockBuffer(buffer, BUFFER_LOCK_SHARE); /* * We copy the page into local storage to avoid holding pin on the @@ -335,7 +336,7 @@ bt_page_items(PG_FUNCTION_ARGS) uargs->page = palloc(BLCKSZ); memcpy(uargs->page, BufferGetPage(buffer), BLCKSZ); - ReleaseBuffer(buffer); + UnlockReleaseBuffer(buffer); relation_close(rel, AccessShareLock); uargs->offset = FirstOffsetNumber; @@ -466,6 +467,8 @@ bt_metap(PG_FUNCTION_ARGS) errmsg("cannot access temporary tables of other sessions"))); buffer = ReadBuffer(rel, 0); + LockBuffer(buffer, BUFFER_LOCK_SHARE); + page = BufferGetPage(buffer); metad = BTPageGetMeta(page); @@ -492,8 +495,7 @@ bt_metap(PG_FUNCTION_ARGS) result = HeapTupleGetDatum(tuple); - ReleaseBuffer(buffer); - + UnlockReleaseBuffer(buffer); relation_close(rel, AccessShareLock); PG_RETURN_DATUM(result); |