CountDownLatch是什么？
CountDownLatch是Java中一个同步工具类，用于控制多个线程的执行顺序。它可以让某个线程一直等待，直到其他线程完成各自的操作后再继续执行。CountDownLatch通过一个计数器来实现，计数器的初始值为线程数量，每当一个线程完成任务后，计数器的值就会减1，当计数器的值变为0时，等待的线程就会被唤醒继续执行...
ORA-55366: unknown namespace prefix “string”
文档解释ORA-55366:unknownnamespaceprefix“string”Cause:AnattemptwasmadetomakeuseofanundefinednamespaceprefixinOracleVirtualPrivateDatabase(VPD)metadata.A...
ORA-24167: incompatible rule engine objects, cannot downgrade
文档解释ORA-24167:incompatibleruleengineobjects,cannotdowngradeCause:thereareruleengineobjectsinthedatabasethatcannotbedowngraded.Action:checkutlincmp.sqlandremovea...
ORA-39500: failed to notify CRS of a Startup/Shutdown event for database “string”, instance “string” (ignored)
文档解释ORA-39500:failedtonotifyCRSofaStartup/Shutdowneventfordatabase“string”,instance“string”(ignored)Cause:Theinstancewasunabletoobtainth...
ORA-16574: switchover disallowed when required databases are shut down
文档解释ORA-16574:switchoverdisallowedwhenrequireddatabasesareshutdownCause:Switchoverfailedbecauseeithertheprimarydatabaseorthedesignatedstandbydatabasewereshutdow...
ORA-24536: Warning – column authorization unknown.
文档解释ORA-24536:Warning–columnauthorizationunknown.Cause:Columnsecurityisunknownforoneormorecolumns.Action:Verifythefetcheddata.Itmayormaynotcontainameaning...
ORA-16830: primary isolated from fast-start failover partners longer than FastStartFailoverThreshold seconds: shutting down
文档解释ORA-16830:primaryisolatedfromfast-startfailoverpartnerslongerthanFastStartFailoverThresholdseconds:shuttingdownCause:Theprimarydatabasewasisolatedfrombothth...
ORA-29264: unknown or unsupported URL scheme
文档解释ORA-29264:unknownorunsupportedURLschemeCause:TheURLschemewasunknownorunsupported.Action:ChecktheURLtomakesurethattheschemeisvalidandsupported.ORA-29264是由于访问...