TLA  Line data    Source code

       1                 : /*-------------------------------------------------------------------------
       2                 :  *
       3                 :  * xlogstats.c
       4                 :  *      Functions for WAL Statitstics
       5                 :  *
       6                 :  * Copyright (c) 2022-2023, 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 CBC          16 : 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              16 :     *fpi_len = 0;
      34              28 :     for (block_id = 0; block_id <= XLogRecMaxBlockId(record); block_id++)
      35                 :     {
      36              12 :         if (!XLogRecHasBlockRef(record, block_id))
      37 UBC           0 :             continue;
      38                 : 
      39 CBC          12 :         if (XLogRecHasBlockImage(record, block_id))
      40 UBC           0 :             *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 CBC          16 :     *rec_len = XLogRecGetTotalLen(record) - *fpi_len;
      48              16 : }
      49                 : 
      50                 : /*
      51                 :  * Store per-rmgr and per-record statistics for a given record.
      52                 :  */
      53                 : void
      54              16 : XLogRecStoreStats(XLogStats *stats, XLogReaderState *record)
      55                 : {
      56                 :     RmgrId      rmid;
      57                 :     uint8       recid;
      58                 :     uint32      rec_len;
      59                 :     uint32      fpi_len;
      60                 : 
      61              16 :     Assert(stats != NULL && record != NULL);
      62                 : 
      63              16 :     stats->count++;
      64                 : 
      65              16 :     rmid = XLogRecGetRmid(record);
      66                 : 
      67              16 :     XLogRecGetLen(record, &rec_len, &fpi_len);
      68                 : 
      69                 :     /* Update per-rmgr statistics */
      70                 : 
      71              16 :     stats->rmgr_stats[rmid].count++;
      72              16 :     stats->rmgr_stats[rmid].rec_len += rec_len;
      73              16 :     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              16 :     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              16 :     if (rmid == RM_XACT_ID)
      91               4 :         recid &= 0x07;
      92                 : 
      93              16 :     stats->record_stats[rmid][recid].count++;
      94              16 :     stats->record_stats[rmid][recid].rec_len += rec_len;
      95              16 :     stats->record_stats[rmid][recid].fpi_len += fpi_len;
      96              16 : }