sql - Oracle 10 optimizer from RULE to COST: why? -

Oracle decided to dismiss rule-based optimizer from version 10g, cost-based one for only one option Left in the form.

I think that a rule-based adapter has always been the incomparable positive side of being predictable instead I changed the execution plans to Oracle 10G by night and day. That can be performed like a turtle.

What can be the reason behind this change?

Because whatever you can do with RBO , CBO Can be done with . The rule may also be based on the

CBO - besides, you can decide "rule" itself.

To create your "rule", you indicate your query or who will indicate this to you. As a result, you have the execution plan stable.

The outline is stored in a system schema called OUTLN , they are editable.

  For me, I always indicate your ongoing problems in a production database.








03:22

















Get link





Facebook





X





Pinterest





Email





Other Apps




Comments





Post a Comment







Popular Posts




linux - C++: undefined reference to `sd_notify' -



    i'm new c++. problem have process creates lot of processes, want identify(get pid) of 1 of children. looping through children take lot of resources(don't ask why). i'm trying pid of process (somehow) identifying if uses sd_notify  , pid(i don't if possible). i'm using ubuntu 14.04 , created little test program:   #include <systemd/sd-daemon.h> #include <stdio.h>  int main() {   int a;   = sd_notify(0, "ready=1");   printf("%d -> \n", a);   fflush(stdout); }   but gives me error saying undefined reference 'sd_notify' .   p.s  found sd_notify  systemd systems. equivalent of in upstart systems? or how can make sure process i'm searching doen't use function? or possible log messages send processes using sd_notify ?          try installing libsystemd-daemon-devel  , compile using   g++ -o sig sig.cpp -lsystemd-daemon       











server - Httpd(apache) is not starting on fedora 23 -



    i tried install nginx , didn't work. after tried install , configure apache(httpd) server on fedora23 dist. server doesn't want start namely doesn't work , returns errors , when try start it: sudo systemctl start httpd  job httpd.service failed because control process exited error code. see "systemctl status httpd.service" , "journalctl -xe" details.   , after saw logs in journalctl -xe . shows this:       jun 28 11:26:49 cyber audit[15981]: cred_refr pid=15981 uid=0 auid=1000 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 msg='op=pam:s jun 28 11:26:49 cyber sudo[15981]: pam_systemd(sudo:session): cannot create session: running in session jun 28 11:26:49 cyber kernel: audit: type=1105 audit(1467095209.363:842): pid=15981 uid=0 auid=1000 ses=1 subj=unconfined_u:unconfined_r:unconfined_t: jun 28 11:26:49 cyber sudo[15981]: pam_unix(sudo:session): session opened user root (uid=0) jun 28 11:26:49 cyber audit[15981]: user_start pid=1...






ios - Swift: Realm accessed from incorrect thread -



    i pass previous view controller. want show data save in other view controller.       override func prepareforsegue(segue: uistoryboardsegue, sender: anyobject?) {     if (segue.identifier == "beacons") {           let nav = segue.destinationviewcontroller as! uinavigationcontroller         let svc = nav.topviewcontroller as! beaconcharacteristicviewcontroller         svc.selectedlist = sender as! beacons       }   and         var selectedlist : beacons!   and code error reason.   i don't use primary key or have use it.       func loadproperties(){        let beacons = selectedlist        let priority = dispatch_queue_priority_default        dispatch_async(dispatch_get_global_queue(priority, 0)) {          do{             try uirealm.write({ () -> void in                  beacons.uuid = self.beaconuuid.text!                 print("uuid = \(beacons.uuid)")                  beacons.major = self.beaconmajor.text!                 print("uuid = \(beacons.u...








Powered by Blogger

Brennenstuhl

Search This Blog

sql - Oracle 10 optimizer from RULE to COST: why? -

Comments

Post a Comment