Обсуждение: [Beginner Question]What is query jumbling?
Hi community,
I am reading the 'Generate code for query jumbling through gen_node_support.pl' (https://www.postgresql.org/message-id/E1pMk51-000puf-55%40gemulon.postgresql.org) to understand the principle of the postgres's node, but I really don't know the meaning of the word 'query jumbling'.
Can someone provide me some advice?
Thanks in advance!
Yours,
Wen Yi
On 7/17/23 05:23, Wen Yi wrote: > Hi community, > I am reading the 'Generate code for query jumbling through > gen_node_support.pl' > (https://www.postgresql.org/message-id/E1pMk51-000puf-55%40gemulon.postgresql.org) to understand the principle of the postgres'snode, but I really don't know the meaning of the word 'query jumbling'. > > Can someone provide me some advice? > Thanks in advance! > Stuff like this is usually explained somewhere in the code base, so "git grep" is your friend. In this case it's probably good to read the comment in src/backend/nodes/queryjumblefuncs.c which says: * Normalization is implemented by fingerprinting queries, selectively * serializing those fields of each query tree's nodes that are judged * to be essential to the query. This is referred to as a query jumble. So "jumbling" is a process to generate a "normalized" query. regards -- Tomas Vondra EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company