TLA  Line data    Source code

       1                 : /*--------------------------------------------------------------------------
       2                 :  *
       3                 :  * test_ginpostinglist.c
       4                 :  *      Test varbyte-encoding in ginpostinglist.c
       5                 :  *
       6                 :  * Copyright (c) 2019-2023, PostgreSQL Global Development Group
       7                 :  *
       8                 :  * IDENTIFICATION
       9                 :  *      src/test/modules/test_ginpostinglist/test_ginpostinglist.c
      10                 :  *
      11                 :  * -------------------------------------------------------------------------
      12                 :  */
      13                 : #include "postgres.h"
      14                 : 
      15                 : #include "access/gin_private.h"
      16                 : #include "access/ginblock.h"
      17                 : #include "access/htup_details.h"
      18                 : #include "fmgr.h"
      19                 : 
      20 CBC           1 : PG_MODULE_MAGIC;
      21                 : 
      22               2 : PG_FUNCTION_INFO_V1(test_ginpostinglist);
      23                 : 
      24                 : /*
      25                 :  * Encodes a pair of TIDs, and decodes it back. The first TID is always
      26                 :  * (0, 1), the second one is formed from the blk/off arguments. The 'maxsize'
      27                 :  * argument is passed to ginCompressPostingList(); it can be used to test the
      28                 :  * overflow checks.
      29                 :  *
      30                 :  * The reason that we test a pair, instead of just a single TID, is that
      31                 :  * the GinPostingList stores the first TID as is, and the varbyte-encoding
      32                 :  * is only used for the deltas between TIDs. So testing a single TID would
      33                 :  * not exercise the varbyte encoding at all.
      34                 :  *
      35                 :  * This function prints NOTICEs to describe what is tested, and how large the
      36                 :  * resulting GinPostingList is. Any incorrect results, e.g. if the encode +
      37                 :  * decode round trip doesn't return the original input, are reported as
      38                 :  * ERRORs.
      39                 :  */
      40                 : static void
      41               4 : test_itemptr_pair(BlockNumber blk, OffsetNumber off, int maxsize)
      42                 : {
      43                 :     ItemPointerData orig_itemptrs[2];
      44                 :     ItemPointer decoded_itemptrs;
      45                 :     GinPostingList *pl;
      46                 :     int         nwritten;
      47                 :     int         ndecoded;
      48                 : 
      49               4 :     elog(NOTICE, "testing with (%u, %d), (%u, %d), max %d bytes",
      50                 :          0, 1, blk, off, maxsize);
      51               4 :     ItemPointerSet(&orig_itemptrs[0], 0, 1);
      52               4 :     ItemPointerSet(&orig_itemptrs[1], blk, off);
      53                 : 
      54                 :     /* Encode, and decode it back */
      55               4 :     pl = ginCompressPostingList(orig_itemptrs, 2, maxsize, &nwritten);
      56               4 :     elog(NOTICE, "encoded %d item pointers to %zu bytes",
      57                 :          nwritten, SizeOfGinPostingList(pl));
      58                 : 
      59               4 :     if (SizeOfGinPostingList(pl) > maxsize)
      60 UBC           0 :         elog(ERROR, "overflow: result was %zu bytes, max %d",
      61                 :              SizeOfGinPostingList(pl), maxsize);
      62                 : 
      63 CBC           4 :     decoded_itemptrs = ginPostingListDecode(pl, &ndecoded);
      64               4 :     if (nwritten != ndecoded)
      65 UBC           0 :         elog(NOTICE, "encoded %d itemptrs, %d came back", nwritten, ndecoded);
      66                 : 
      67                 :     /* Check the result */
      68 CBC           4 :     if (!ItemPointerEquals(&orig_itemptrs[0], &decoded_itemptrs[0]))
      69 UBC           0 :         elog(ERROR, "mismatch on first itemptr: (%u, %d) vs (%u, %d)",
      70                 :              0, 1,
      71                 :              ItemPointerGetBlockNumber(&decoded_itemptrs[0]),
      72                 :              ItemPointerGetOffsetNumber(&decoded_itemptrs[0]));
      73                 : 
      74 CBC           4 :     if (ndecoded == 2 &&
      75               3 :         !ItemPointerEquals(&orig_itemptrs[0], &decoded_itemptrs[0]))
      76                 :     {
      77 UBC           0 :         elog(ERROR, "mismatch on second itemptr: (%u, %d) vs (%u, %d)",
      78                 :              0, 1,
      79                 :              ItemPointerGetBlockNumber(&decoded_itemptrs[0]),
      80                 :              ItemPointerGetOffsetNumber(&decoded_itemptrs[0]));
      81                 :     }
      82 CBC           4 : }
      83                 : 
      84                 : /*
      85                 :  * SQL-callable entry point to perform all tests.
      86                 :  */
      87                 : Datum
      88               1 : test_ginpostinglist(PG_FUNCTION_ARGS)
      89                 : {
      90               1 :     test_itemptr_pair(0, 2, 14);
      91               1 :     test_itemptr_pair(0, MaxHeapTuplesPerPage, 14);
      92               1 :     test_itemptr_pair(MaxBlockNumber, MaxHeapTuplesPerPage, 14);
      93               1 :     test_itemptr_pair(MaxBlockNumber, MaxHeapTuplesPerPage, 16);
      94                 : 
      95               1 :     PG_RETURN_VOID();
      96                 : }