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When a TCP / IP connection from one machine to another is used , and a target file is specified , the target file will be written on the machine where the backend is running rather than the user 's machine . These operators must be named ' <' and '> ' ; you do not have any choice in the matter , since there is no provision for specifying them explicitly . The input argument types to the function must be specified , as only the function with the given name and argument types will be removed . Caution Unexpected results may be obtained if a cache setting greater than one is used for a sequence object that will be used concurrently by multiple backends . Headquartered in Los Angeles , Calif ., Northrop Grumman employs more than 125,000 people in all 50 states and 25 countries . So , if you want to use a combination of fields which is not unique as a secondary key , you really do n't have to specify anything - just start retrieving by that combination ! The ordinary strategy for this situation is to notify all other backends that they must terminate and then reinitialize the shared memory and semaphores . A message like this does not mean that you've run out of disk space ; it means that your kernel 's limit on the number of SysV semaphores is smaller than the number Postgres wants to create . The rule system got more and more out of sync with their capabilities and it became harder and harder to start fixing it . It must not be root , bin , or any other account with special access rights , as that would create a security risk.Log in to the Postgres superuser account . This shows , that the optimizer does not realize that the qualification for the hostname on computer could also be used for an index scan on software when there are multiple qualification expressions combined with AND , what he does in the regexp version of the query . The HASHES flag indicates to the query optimizer that a hash join may safely be used with this operator . Furthermore , although multiple backends are guaranteed to allocate distinct sequence values , the values may be generated out of sequence when all the backends are considered . In the querytree the rangetable entries are referenced by index rather than by name , so here it does n't matter if there are duplicate names as it would in an SQL statement . I think there are only a few situations out in the real world , where such a construct is necessary . Now we face Al with the problem that the Blues Brothers appear in his shop and want to buy some new shoes , and as the Blues Brothers are , they want to wear the same shoes . So , this level emulates serial transaction execution , as if transactions would be executed one after another , serially , rather than concurrently . The main motivation for partial indices is this : if all of the queries you ask that can profitably use an index fall into a certain range , why build an index over the whole table and suffer the associated space / time costs ? An engineering degree can also open doors to other professions such as medicine , business administration , law , computer development or others . Hence , if you want your function to be used on different architectures , we recommend that you do not overload C function names .