You can scan a range of items and selectively delete or change some of them usingt.editRange. For example, the following code adds an exclamation mark to each non-boring value and deletes key number 4: vart=newBTree().setRange([ [1,"fun"], [2,"yay"],[4,"whee"],[8,"zany"],...
B-tree implementation in C. Contribute to Grabber/btree.c development by creating an account on GitHub.
假如有这样一列code的值为'AAA','AAB','BAA','BAB' ,如果where code like '%AB'条件,由于前面是 模糊的,所以不能利用索引的顺序,必须一个个去找,看是否满足条件。这样会导致全索引扫描或者全表扫 描。如果是这样的条件where code like 'A % ',就可以查找CODE中A开头的CODE的位置,当碰到B开头的 数据时...
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1. In DBC->del, we only mark the key/data pair deleted (B_DELETE), and mark the cursor to be pointing to a deleted k/d pair(C_DELETED), but we don't effectively remove the k/d from page, unless the cursor is closed and it's ...
#· C · 49 lines · 29 code · 10 blank · 10 comment ·0 complexity· 72f8b9caa64a7930d707121b5f6d1210 MD5 ·raw file /* * contrib/btree_gist/btree_gist.c */ #include"btree_gist.h" PG_MODULE_MAGIC; PG_FUNCTION_INFO_V1(gbt_decompress); ...
BTree (in fact B*Tree) is an efficient ordered key-value map. Meaning: given the key, a BTree index can quickly find a record, a BTree can be scanned in order. it's also easy to fetch all the keys (and records) within a range. ...
pcode=0: iot flags=--- is converted=Ykdxconco 2kdxcosdc 10kdxconro 317kdxcofbo 670=0x29ekdxcofeo 2960=0xb90kdxcoavs 2290kdxlespl 0kdxlende 0kdxlenxt 185672019=0xb112153kdxleprv 0=0x0kdxledsz 0kdxlebksz 8032row#0[3712] flag: ---, lock: 0, len=16col 0; len 6; (6): 41...
// To simplify our code here, we handle cases #1 and #2 the same: // If a node doesn't have enough items, we make sure it does (using a,b,c). // We then simply redo our remove call, and the second time (regardless of // whether we're in case 1 or 2), we'll have...
基于哈希表实现,只有精确匹配索引所有列的查询才有效,对于每一行数据,存储引擎都会对所有的索引列计算一个哈希码(hash code),并且Hash索引将所有的哈希码存储在索引中,同时在索引表中保存指向每个数据行的指针。 图片来源:https://www.javazhiyin.com/40232.html ...