indexing

问题 I would like to know if there is a way to get rid of CDT syntax error warnings when using gcc's " __attribute__ " keyword. It goes without saying that I would not like to switch off CDT syntax check. 回答1: The "ECLIPSE_THINKS_THIS_IS_SET_BUT_GCC_DOESNT" definition (from ams 's answer) really extsts and it called __CDT_PARSER__ . For example: #ifdef __CDT_PARSER__ #define __FILE__ "<file>" #define __LINE__ (-1) #define __DATE__ "<date>" #define __TIME__ "<time>" #endif // #ifdef __CDT_PARSER__

问题 In the software I'm writing one has the ability to search a given table for information. The search form has 5 fields, all which of course correspond to different columns in a table, but all of the fields are optional. My question is in regard to whether or not multi-column indexing will work and the proper way to build a query for it. If I have a single index across 5 columns, and I build a query to search them, when it comes to fields in this index I'm not searching, do I do something like:

问题 Does anybody have a working example of how to configure a cluster of nodes to share an index using the infinispan directory provider? All the documentation on Infinispan (the documentation is seriously lacking btw) implies that it should be as easy as having some properties set but no matter how I try I cannot get it to work. The nodes in the cluster find eachother fine and I can do get operations on one node and get object that were put on another. But as soon as I do queries (use the index)

问题 I had trying to check whether a index exists in the RestHighLevelClient of elasticsearch 6.2.1 presently I am using using following code try { OpenIndexRequest openIndexRequest = new OpenIndexRequest(indexName); client.indices().open(openIndexRequest, header).isAcknowledged(); } catch (ElasticsearchStatusException ex) { String m = "Elasticsearch exception [type=index_not_found_exception, reason=no such index]"; if (m.equals(ex.getMessage())) { //TODO In case index does not exists } } it works

问题 I have a table that has IDs and Strings and I need to be able to properly index for searching for the end of the strings. How we are currently handling it is copying the information into another table and reversing each string and indexing it normally. What I would like to do is use some kind of index that allows to search in reverse. Example Data: F7421kFSD1234 d7421kFSD1235 F7541kFSD1236 d7421kFSD1234 F7421kFSD1235 b8765kFSD1235 d7421kFSD1234 The way our users usually input thier search is

问题 I have a regexp: /(alpha)|(beta)|(gamma)/gi Some text to match against: Betamax. Digamma. Alphabet. Hebetation. The matches are: beta, gamma, alpha, beta The values I am looking would be: 1,2,0,1 ...can I ascertain the index of the group that matched in the regexp? 回答1: To access the groups, you will need to use .exec() repeatedly: var regex = /(alpha)|(beta)|(gamma)/gi, str = "Betamax. Digamma. Alphabet. Hebetation."; for (var nums = [], match; match = regex.exec(str); ) nums.push(match

问题 i'm using for the first time Postgresql and i'm trying to create a search engine in my website. i have this table: CREATE TABLE shop ( id SERIAL PRIMARY KEY, name TEXT NOT NULL, description TEXT, address TEXT NOT NULL, city TEXT NOT NULL ); Then i created an index for every field of the table (is this the right way? Or maybe i can create one index for all fields?): CREATE INDEX shop_name_fts ON shop USING gin(to_tsvector('italian', name)); CREATE INDEX shop_desc_fts ON shop USING gin(to

问题 So let's say I have a table with two indexes - one on column a and one on columns a, b and c. I've noticed that, depending on the order of the columns in the index definition that MySQL might wind up using the single column index instead of the multi column index, even if all three columns in the multi column index are being referenced in the ON part of the JOIN. This kinda begs the question... how does one figure out the ideal ordering of the columns? Do you just have to brute force it? 回答1:

问题 I have a matrix. mat = array([ [ 0, 1, 2, 3], [ 4, 5, 6, 7], [ 8, 9, 10, 11] ]) I'd like to get the sum of the rows at certain indices: eg. ixs = np.array([0,2,0,0,0,1,1]) I know I can compute the answer as: mat[ixs].sum(axis=0) > array([16, 23, 30, 37]) The problem is ixs may be very long, and I don't want to use all the memory to create the intermediate product mat[ixs], only to reduce it again with the sum. I also know I could simply count up the indices and use multiplication instead. np

问题 I need some help figuring this out. I'm trying to get Mysql to use an index on a DATETIME field. Mysql decides not to use the index if there's other (not used) fields in the table. Consider the two cases below: A simple table with 2 fields works fine : DROP TABLE IF EXISTS datetime_index_test; CREATE TABLE datetime_index_test ( id INT UNSIGNED NOT NULL AUTO_INCREMENT , created DATETIME NOT NULL , PRIMARY KEY (id) , INDEX (created) ) ENGINE = InnoDB ; INSERT INTO datetime_index_test (created)