Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * xlogstats.c
       4             :  *      Functions for WAL Statitstics
       5             :  *
       6             :  * Copyright (c) 2022-2024, PostgreSQL Global Development Group
       7             :  *
       8             :  * IDENTIFICATION
       9             :  *      src/backend/access/transam/xlogstats.c
      10             :  *
      11             :  *-------------------------------------------------------------------------
      12             :  */
      13             : #include "postgres.h"
      14             : 
      15             : #include "access/xlogreader.h"
      16             : #include "access/xlogstats.h"
      17             : 
      18             : /*
      19             :  * Calculate the size of a record, split into !FPI and FPI parts.
      20             :  */
      21             : void
      22      650320 : XLogRecGetLen(XLogReaderState *record, uint32 *rec_len,
      23             :               uint32 *fpi_len)
      24             : {
      25             :     int         block_id;
      26             : 
      27             :     /*
      28             :      * Calculate the amount of FPI data in the record.
      29             :      *
      30             :      * XXX: We peek into xlogreader's private decoded backup blocks for the
      31             :      * bimg_len indicating the length of FPI data.
      32             :      */
      33      650320 :     *fpi_len = 0;
      34     1374104 :     for (block_id = 0; block_id <= XLogRecMaxBlockId(record); block_id++)
      35             :     {
      36      723784 :         if (!XLogRecHasBlockRef(record, block_id))
      37         206 :             continue;
      38             : 
      39      723578 :         if (XLogRecHasBlockImage(record, block_id))
      40       20246 :             *fpi_len += XLogRecGetBlock(record, block_id)->bimg_len;
      41             :     }
      42             : 
      43             :     /*
      44             :      * Calculate the length of the record as the total length - the length of
      45             :      * all the block images.
      46             :      */
      47      650320 :     *rec_len = XLogRecGetTotalLen(record) - *fpi_len;
      48      650320 : }
      49             : 
      50             : /*
      51             :  * Store per-rmgr and per-record statistics for a given record.
      52             :  */
      53             : void
      54      138220 : XLogRecStoreStats(XLogStats *stats, XLogReaderState *record)
      55             : {
      56             :     RmgrId      rmid;
      57             :     uint8       recid;
      58             :     uint32      rec_len;
      59             :     uint32      fpi_len;
      60             : 
      61             :     Assert(stats != NULL && record != NULL);
      62             : 
      63      138220 :     stats->count++;
      64             : 
      65      138220 :     rmid = XLogRecGetRmid(record);
      66             : 
      67      138220 :     XLogRecGetLen(record, &rec_len, &fpi_len);
      68             : 
      69             :     /* Update per-rmgr statistics */
      70             : 
      71      138220 :     stats->rmgr_stats[rmid].count++;
      72      138220 :     stats->rmgr_stats[rmid].rec_len += rec_len;
      73      138220 :     stats->rmgr_stats[rmid].fpi_len += fpi_len;
      74             : 
      75             :     /*
      76             :      * Update per-record statistics, where the record is identified by a
      77             :      * combination of the RmgrId and the four bits of the xl_info field that
      78             :      * are the rmgr's domain (resulting in sixteen possible entries per
      79             :      * RmgrId).
      80             :      */
      81             : 
      82      138220 :     recid = XLogRecGetInfo(record) >> 4;
      83             : 
      84             :     /*
      85             :      * XACT records need to be handled differently. Those records use the
      86             :      * first bit of those four bits for an optional flag variable and the
      87             :      * following three bits for the opcode. We filter opcode out of xl_info
      88             :      * and use it as the identifier of the record.
      89             :      */
      90      138220 :     if (rmid == RM_XACT_ID)
      91         860 :         recid &= 0x07;
      92             : 
      93      138220 :     stats->record_stats[rmid][recid].count++;
      94      138220 :     stats->record_stats[rmid][recid].rec_len += rec_len;
      95      138220 :     stats->record_stats[rmid][recid].fpi_len += fpi_len;
      96      138220 : }