今天无意发现了个PostgreSQL环境,线上学习了下,一般的数据注射(读写数据库)差异不大,不做讨论,个人比较关心PostgreSQL的文件读取和命令执行方面。 1,文件读取/写入 PostgreSQL 8.1 以后提供了一组现成的文件操作函数 pg_logdir_ls()、pg_ls_dir()、pg_file_rename()、pg_file_write()、 pg_read_file()、pg_...
\copy ... perform SQL COPY with data stream to the client host \echo [STRING] write string to standard output \i FILE execute commands from file \o [FILE] send all query results to file or |pipe \qecho [STRING] write string to query output stream (see \o) Informational (options: S...
.smgr_open=mdopen,.smgr_close=mdclose,.smgr_create=mdcreate,.smgr_exists=mdexists,.smgr_unlink=mdunlink,.smgr_extend=mdextend,.smgr_zeroextend=mdzeroextend,.smgr_prefetch=mdprefetch,.smgr_readv=mdreadv,.smgr_writev=mdwritev,.smgr_writeback=mdwriteback,.smgr_nblocks=mdnblocks,.smgr_...
#full_page_writes = on # 当这个参数为打开时,PostgreSQL服务器在一个检查点之后的页面的第一次修改期间将每个页面的全部内容写到 WAL 中。默认值是on wal_compression = on # 当这个参数为on时,如果full_page_writes 为打开或者处于基础备份期间,PostgreSQL服务器 会压缩写入到 WAL 中的完整页面镜像。 #wal...
0/C08CD30Latest checkpoint's REDO WAL file: 00000004000000000000000CLatest checkpoint's TimeLineID: 4Latest checkpoint's PrevTimeLineID: 4Latest checkpoint's full_page_writes: onLatest checkpoint's NextXID: 0:663Latest checkpoint's NextOID: 57347Latest checkpoint's NextMultiXactId: 1Latest checkpo...
write_function_list = '' # Comma separated list of function names # that write to database # Regexp are accepted # If both read_only_function_list and write_function_list # is empty, function's volatile property is checked. # If it's volatile, the function is regarded as a ...
starting backgroundWALreceiverpg_basebackup:created temporary replication slot"pg_basebackup_119924"32567/32567kB(100%),2/2tablespacespg_basebackup:write-ahead log end point:0/8000100pg_basebackup:waitingforbackground process to finish streaming...pg_basebackup:syncing data to disk...pg_basebackup:...
背景是 os-内核本身在处理 DRAM page落盘的时候默认是通过 write-back 机制,write-back的pd-flush 内核线程刷 内存脏页失败了(可能os硬件问题,内存脏页的存储其实对 pg 来说 是 checkpoint 刷 buffers 的第一个阶段,只是将buffers 数据 写入到os的 page-cache中,后续才会调用fsycn),当时内核对于这种脏页的错误处...
state->status = TSS_WRITEFILE; dumptuples(state); // 写元组到文件,在内部会将元组的指针偏移量转换为文件偏移量 break; case TSS_WRITEFILE: // 随后写元祖 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. ...
PostgreSQL 10对一些目录也改名:Rename write-ahead log directory pg_xlog to pg_wal rename transaction status directory pg_clog to pg_xact PostgreSQL 9.X,同步复制只能支持一个同步的备库,PostgtreSQL 10 可以支持多个同步的standby,这称为“Quorum Commit”,同步复制的配置发生如下变化:...