oracle 11g归档日志研究_1

第2块的数据格式：

typedef struct scn {
    uint32_t scnbase;
    uint16_t scnwrapper;
    uint16_t filler;
}Redo_scn;

typedef struct fh1 {
    Redo_bh blockhead;
    uint32_t unknown0;
    uint32_t comvsn;        //Compatibility Vsn
    uint32_t dbid;
    uint8_t dbname[8];      //"ORCL"(sid)
    uint32_t controlseq;
    uint32_t filesize;
    uint32_t blocksize;
    uint16_t filenum;
    uint16_t filetype;
    uint32_t activid;
    uint8_t nouse0[36];     //0
    uint8_t descript[64];
    uint32_t nab;           //next available block
    uint32_t resetcount;
    Redo_scn resetscn;
    uint32_t hws;           //后3字节为0
    uint32_t thread;
    Redo_scn lowscn;
    uint32_t lowscntime;
    Redo_scn nextscn;
    uint32_t nextscntime;
    uint32_t unknown11;
    Redo_scn enablescn;
    uint32_t enablescntime;
    Redo_scn thrclosescn;
    uint32_t thrclosescntime;
    uint8_t unknown13[52];
    Redo_scn prevresetscn;
    uint32_t prevresetcount;
    uint8_t nouse1[152];    //0
    uint8_t unknown14[36];
    uint8_t nouse2[28];     //0
}Redo_fh1;

第1块与其他块完全不同，它不含有块头，也不被包含在块总数之内。从第2块开始，所有的数据块的前16个字节为块头，格式：

typedef struct bh {
    uint32_t signature;     //签名
    uint32_t blocknum;      //块号
    uint32_t sequence;      //顺序号
    uint16_t offset;        //最高位1需过滤掉
    uint16_t checksum;
}Redo_bh;

下面详细研究归档日志。

oracle 11g归档日志研究_1

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