table_open ->relation_open ->LockRelationOid ->LockAcquireExtended ->WaitOnLock // if you can't get the lock immediately, then need to wait for others releasing the lock ->ProcSleep ->CheckDeadLock ->DeadLockCheck 死锁释放的入口函数是DeadLockCheckRecurse(),其将死锁处理后的等待队列存放在...
postgres=#selectoidfrompg_classwhererelname='map_test';oid---27740postgres=#selectattrelid,attname,atttypid,attlen,attnumfrompg_attributewhereattrelid=27740;attrelid|attname|atttypid|attlen|attnum---+---+---+---+---27740|tableoid|26|4|-627740|cmax|29|4|-527740|xmax|28|4|-427740|c...
palloc(sizeof(dirtyread_ctx_state));inter_call_data->rel=table_open(relid,AccessShareLock);inter_call_data->desc=RelationGetDescr(inter_call_data->rel);if(get_call_result_type(fcinfo,NULL,&tupdesc)!=TYPEFUNC_COMPOSITE)elog(ERROR,"return type must be a row type");funcctx->tuple_desc=B...
# table cache performance settings table_open_cache = 4096 #所有线程打开表数 table_definition_cache = 4096 #定义在高速缓冲中存储的表定义数量, #定义一次可打开的innodb文件数(每个表)的软限制(与innodb_open_files取最大值) table_open_cache_instances = 64 #打开表缓存实例的数量 #每个表缓存实例大小...
•绑定游标(Bound Cursor):声明时即绑定特定查询,如DECLARE curs2 CURSOR FOR SELECT * FROM table;。无需单独执行OPEN,只需确保相关变量赋值完成即可开始使用。 1.3. 游标生命周期 游标生命周期包括声明、打开、读取、关闭与重置等阶段: ...
open_sync 3850.219 ops/sec 260 usecs/op Compare file sync methods using two 8kB writes: (in wal_sync_method preference order, except fdatasync is Linux's default) open_datasync 2469.646 ops/sec 405 usecs/op fdatasync 4412.266 ops/sec 227 usecs/op ...
# open_sync 用open()选项O_SYNC写 WAL 文件 #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...
ALTER TABLE Product RENAME TO Product; 13、查询语句 (1) 查询全部列 Select * from <表名>; 星号(*)代表全部列的意思。 (2) 查询指定列 SELECT <列名>,<列名>,…… FROM <表名>; 注:查询多列时,需要使用逗号进行分隔。查询结果中列的顺序和 ...
This will open a new window to create a New Table. Supply a name of your new table and then click on Columns. Now in the columns window, you can add columns you want and their data types by clicking "Add" and clicking on "Ok" after you finish supplying a name and data type for ...
We primarily use Macs and Ubuntu Linux at OpenTable. We'll be happy to try to help out otherwise, but other platforms, such as Windows depend primarily on community support. We simply don't have the time or hardware. Happy to merge PRs though ...