Submitting a query inside the backend

<p class="MsoNormal"><span lang="EN-US" style="">As part of a research project I would like to change the source code
ofPostgres. There, I want to do the following: I want to stop the optimizer at some place, issue a query from the
optimizerand use the result of the query to continue the optimization process.</span><p class="MsoNormal"><span
lang="EN-US"style="">Is there a good and clean way how I could do this? I want to submit another query inside the
existingconnection and optimizer code. <span style=""> </span>Is there some function I could use? I don’t want to do a
hardcodedscan of a table, I want to build a query string and use the parser, analyzer, optimizer, and executer to
submitthe query.</span><p class="MsoNormal"><span lang="EN-US" style="">Thanks a lot!</span><p class="MsoNormal"><span
lang="EN-US"style="">Robert</span>