What is the form of the unique key? I'm a bit confused here by your comment: "which can contain one or multi fields".
But it seems like IndexWriter.deleteDocuments should work here. It's easy if your PKs are single terms, there's even a deleteDocuments(Term[]) form. But this really *requires* that your PKs are single terms in a field. If your PKs are some sort of composite field, perhaps the iw.DeleteDocuments(Query[]) would help where each query is enough to uniquely identify your document. Best Erick On Mon, Nov 16, 2009 at 12:15 PM, java8964 java8964 <java8...@hotmail.com>wrote: > > Hi, > > In our application, we will allow the user to create a primary key defined > in the document. We are using lucene 2.9. > In this case, when we index the data coming from the client, if the > metadata contains the primary key defined, > we have to do the search/update for every row based on the primary key. > > Here is our current problems: > > 1) If the meta data coming from client defined a primary key (which can > contain one or multi fields), > then for the data supplied from the client, we have to make sure that > later row will override the previous row, if they have the same primary key > as the data. > 2) To do the above, we have to loop through the data first, to check if any > later rows containing the same PK as the previous rows, so we will build the > MAP in the memory to override the previous one by the latest ones. > This is a very expensive operation. > 3) Even in this case, for every row after the above filter steps, we still > have to search the current index to see if any data with the same PK exist > or not. So we have to do the remove before we add the new data in the index. > > I want to know if anyone has the same requirement like this PK using the > lucene? What is the best way to index data in this case? > > First, I am thinking if it is possible to remove the above step2? > the problem for the lucene is that when we add document in the index, we > can NOT search it before commit it. > But we only commit once when the whole data file is finished. So we have to > loop through the data once to check to see if any data sharing the same PK > in the data file. > I am wondering if there is a way in the index writer, before it commits > anything, when we add the new document into it, it can do the merging of the > PK data? What I mean is that if the same PK data already exist in any > previous added document, just remove it and let the new added data > containing the same PK data take the place? If we can do this, then the > whole pre checking data step can be removed. > > Second, for the above step 3, if the searching the existing index is NOT > avoidable, what is the fast way to search by the PK? Of course we already > indexed all the PK fields. When we add new data, we have to search every row > of existing index by the PK fields, to see if it exist or not. If it does, > remove it and add the new one. > We constructor the query by the PK fields at run time, then search it row > by row. This is also very bad as the indexing the data for performance. > > Here is what I am thinking? > 1) Can I use the Indexreader.term(terms)? I heard it is much faster than > the query searching? Is that right? > 2) Currently we are do the search row by row? Should I do it in batching? > Like I will combine 100 PK search into one search, using Boolean term? So > one search will give me back all the data in this 100 PK which are in the > index. Then I can remove them from the index using the result set. In this > case, I only need to do 1/100 search requests as before? This will much > faster than row by row in theory. > > > Please let me know any feedbacks? If you ever dealed with PK data support, > please share some thougths and experience. > > Thanks for your kind help. > > _________________________________________________________________ > Hotmail: Free, trusted and rich email service. > http://clk.atdmt.com/GBL/go/171222984/direct/01/ >
