Changes between Version 17 and Version 18 of ImplementSortingMethodsBeforeGistIndexBuilding

Timestamp:

08/23/21 06:49:35 (3 years ago)

Author:

HanwGeek

Comment:

--

ImplementSortingMethodsBeforeGistIndexBuilding

@@ -127 +127 @@
 GiST(Generalized Search Tree) is a generalization data structure of a variety of disk-based height-balanced search trees. Under the high-level API of GiST, structures like b-tree, r-tree can be implemented for data management. PostgreSQL defines a set of process function APIs for elements of the GiST index. Only with these function implementations can a data type be indexed and managed by a GiST structure. In large data scenarios, pre-sorting a batch of data fetched in memory may be a local approximation to the global sorting method. Recent PostgreSQL patch shows that it should speed up the build of a GiST index after some pre-sorting of the data which needs to be indexed. In one fork, the author replaces the GIST_OPTIONS_PROC with GIST_ORDER_PROC to try to define an order for data fetched in memory to sort in order to speed up the subsequent index building process. And I implemented pre-sorting methods in z-order pattern and Hilbert order pattern, Alos tested and compared pre-sorting methods on various data.
 
+**The state of the art BEFORE your GSoC**
+
+The index building process does not change the tuple order in the page and run in a slow speed
+
+**The addition value**
+With the pre-sorting index, the time of building index reduce to the to one-third to one-fifth of the original
+
 **Links**
 
@@ -144 +151 @@
 * Implement a fast Morton/Hilbert hash function for n-dimension geometry objects
 
+[[Image(https://user-images.githubusercontent.com/25524928/130458502-313360a1-01dd-46f0-8ca7-e9cf0147ee6c.png)]]
+
 == Student's Biography ==
 My name is Han WANG. I am a first year graduate student majoring in GIS at Peking University, and will get my Master's degree in 2023. And this is my github(https://github.com/HanwGeek) and my linkedin(https://www.linkedin.com/in/hanwgeek/). I am interested in all cool things. And it is very exciting to join the open source community! My research interest includes massive spatial temporal data management and analysis. Currently, I am working on a machine learning project based on big trajectory data, which is stored in PostgreSQL database and managed by PostGIS.