pgsql 的 pg_user表中没有新创建的用户

如果您在 pg_user 表中找不到新创建的用户，请确保您已经正确地创建了用户并将其添加到了数据库中。您可以使用以下命令在 PostgreSQL 中创建新用户：

CREATE USER username WITH PASSWORD 'password';

将“username”替换为您要创建的用户名，将“password”替换为您要为用户设置的密码。

如果您已经正确地创建了用户，但仍然无法在 pg_user 表中找到它，请尝试重新启动 PostgreSQL 服务器。有时，PostgreSQL 可能没有正确地加载新用户信息，因此重新启动服务器可能会解决问题。

如果您仍然无法在 pg_user 表中找到新用户，则可能存在其他问题，例如权限问题或数据库损坏。在这种情况下，您可能需要进一步调查问题或寻求专业帮助。

相关问题

pgsql 查看表创建时间

你可以使用以下 SQL 查询来查看 PostgreSQL 数据库中表的创建时间：

SELECT pg_stat_user_tables.relname, pg_stat_user_tables.last_analyze, pg_stat_user_tables.last_autoanalyze, pg_stat_user_tables.last_vacuum, pg_stat_user_tables.last_autovacuum, pg_class.reltuples, pg_class.relpages, pg_class.relkind, pg_class.relname, pg_class.relnamespace, pg_namespace.nspname, pg_class.reltuples, pg_class.relpages, pg_class.reltoastrelid, pg_class.reltablespace, pg_class.reloptions, pg_description.description, pg_indexes.indexdef, pg_trigger.tgname, pg_proc.proname, pg_proc.prolang, pg_attrdef.adsrc, pg_constraint.conname, pg_constraint.contype, pg_constraint.conkey, pg_constraint.confkey, pg_constraint.conrelid, pg_constraint.confrelid, pg_constraint.confupdtype, pg_constraint.confdeltype, pg_constraint.confmatchtype, pg_constraint.conislocal, pg_constraint.coninhcount, pg_constraint.connoinherit, pg_constraint.convalidated, pg_constraint.condeferrable, pg_constraint.condeferred, pg_conversion.conname, pg_conversion.connamespace, pg_conversion.conowner, pg_conversion.conforencoding, pg_conversion.contoencoding, pg_cast.castsource, pg_cast.casttarget, pg_cast.castfunc, pg_collation.collname, pg_collation.collnamespace, pg_collation.collowner, pg_collation.collprovider, pg_authid.rolname, pg_authid.rolsuper, pg_authid.rolinherit, pg_authid.rolcreaterole, pg_authid.rolcreatedb, pg_authid.rolcatupdate, pg_authid.rolcanlogin, pg_authid.rolreplication, pg_authid.rolbypassrls, pg_auth_members.member, pg_shdepend.classid, pg_shdepend.objid, pg_shdepend.objsubid, pg_shdepend.refclassid, pg_shdepend.deptype, pg_shdepend.refobjid, pg_shdepend.refobjsubid, pg_seclabel.provider, pg_seclabel.label, pg_depend.classid, pg_depend.objid, pg_depend.objsubid, pg_depend.refclassid, pg_depend.refobjid, pg_depend.refobjsubid, pg_depend.deptype, pg_largeobject_metadata.lomowner, pg_largeobject_metadata.lomacl, pg_largeobject_metadata.lomdesc, pg_largeobject_metadata.loinvafter, pg_largeobject_metadata.loremovable, pg_largeobject_metadata.lobjid, pg_largeobject_metadata.lobjsubid, pg_largeobject_metadata.locreation, pg_largeobject.loid, pg_largeobject.lovalue, pg_inherits.inhrelid, pg_inherits.inhparent, pg_publication.pubname, pg_publication.pubowner, pg_publication.puballtables, pg_publication.pubinsert, pg_publication.pubupdate, pg_publication.pubdelete, pg_publication.pubtruncate, pg_replication_origin.roident, pg_replication_origin.rolastxact, pg_replication_origin.rocommit, pg_replication_origin.rosend, pg_replication_origin.roapply, pg_replication_origin.roident_seq
FROM pg_stat_user_tables
LEFT JOIN pg_class ON pg_stat_user_tables.relid = pg_class.oid
LEFT JOIN pg_namespace ON pg_class.relnamespace = pg_namespace.oid
LEFT JOIN pg_description ON pg_class.oid = pg_description.objoid
LEFT JOIN pg_indexes ON pg_class.oid = pg_indexes.indexrelid
LEFT JOIN pg_trigger ON pg_class.oid = pg_trigger.tgrelid
LEFT JOIN pg_proc ON pg_trigger.tgfoid = pg_proc.oid
LEFT JOIN pg_attrdef ON pg_class.oid = pg_attrdef.adrelid
LEFT JOIN pg_constraint ON pg_class.oid = pg_constraint.conrelid
LEFT JOIN pg_conversion ON pg_namespace.oid = pg_conversion.connamespace
LEFT JOIN pg_cast ON pg_cast.castcontext = 'a'::"char"
LEFT JOIN pg_collation ON pg_collation.collnamespace = pg_namespace.oid
LEFT JOIN pg_authid ON pg_authid.oid = pg_namespace.nspowner
LEFT JOIN pg_auth_members ON pg_auth_members.member = pg_authid.oid
LEFT JOIN pg_shdepend ON pg_class.oid = pg_shdepend.objid
LEFT JOIN pg_seclabel ON pg_class.oid = pg_seclabel.objoid
LEFT JOIN pg_depend ON pg_class.oid = pg_depend.refobjid
LEFT JOIN pg_largeobject_metadata ON pg_class.oid = pg_largeobject_metadata.lobjoid
LEFT JOIN pg_largeobject ON pg_largeobject_metadata.oid = pg_largeobject.loid
LEFT JOIN pg_inherits ON pg_class.oid = pg_inherits.inhrelid
LEFT JOIN pg_publication ON pg_class.oid = pg_publication.pubrelid
LEFT JOIN pg_replication_origin ON pg_replication_origin.roident = pg_depend.refobjid
WHERE pg_stat_user_tables.relname = 'your_table_name';

其中 `your_table_name` 是要查询的表的名称。查询结果中的 `pg_stat_user_tables.last_analyze` 和 `pg_stat_user_tables.last_autoanalyze` 列可以用于确定表的创建时间。

java pg_dump

`pg_dump` 是一个用于备份 PostgreSQL 数据库的工具。它可以将数据库中的数据表、视图、函数等对象转储为 SQL 脚本或二进制文件，并可以用于将数据从一个 PostgreSQL 数据库迁移到另一个 PostgreSQL 数据库。

如果你想在 Java 中使用 `pg_dump` 工具来备份 PostgreSQL 数据库，可以使用 `ProcessBuilder` 类来创建一个进程并执行命令。以下是一个简单的示例代码：

import java.io.File;
import java.io.IOException;

public class PgDumpExample {
    public static void main(String[] args) throws IOException, InterruptedException {
        String dbName = "mydb";
        String dbUser = "myuser";
        String dbPassword = "mypassword";
        String outputFile = "/path/to/output/file.sql";

        ProcessBuilder pb = new ProcessBuilder("pg_dump", "-U", dbUser, "-F", "c", "-b", "-v", "-f", outputFile, dbName);
        pb.environment().put("PGPASSWORD", dbPassword);

        pb.directory(new File("/usr/local/pgsql/bin")); // 设置 pg_dump 命令的工作目录

        Process p = pb.start();
        int exitCode = p.waitFor();
        if (exitCode != 0) {
            System.err.println("备份失败");
        } else {
            System.out.println("备份成功");
        }
    }
}

在这个示例中，我们使用 `ProcessBuilder` 创建了一个 `pg_dump` 命令的进程，并传递了一些参数，如数据库用户名、输出文件路径等。我们还设置了 `PGPASSWORD` 环境变量来传递数据库密码。最后，我们启动进程并等待它的完成。如果进程的退出码为 0，说明备份成功，否则备份失败。