* when told to reset or delete itself. We link the node to its * parent (if any), making the node part of the context tree. * 6. We return to the context-type-specific routine, which finishes * up type-specific initialization. This routine can now do things * that might fail (lik...
you can basically create a system of infinite size. The procedure to set things up is basically the same as that for setting up a single slave. You can easily take base backups from an operational slave (postgresql.conf and pg_hba.conf have to be configured just as...
However, databases don’t just store character strings: they also compare them, build indexes on them, change them to upper case, do regex searches on them, and other things that mean they need know what the characters are and how to manipulate them. So, PostgreSQL needs to know what char...
一、背景 为了分析postgresql代码,了解其执行查询语句的过程,我采用eclipse + gdb集成调试环境,在客户端执行一个查询语句,观察分析其执行流程及重要数据结构...
If pulling up a subquery produces a FROM-list as a direct child of another FROM-list, then we can merge the two FROM-lists together. Once that's done, the subquery is an absolutely integral part of the outer query and will not constrain the join tree search space at all. However, tha...
= NULL) { /* Normal case: allocate the node in TopMemoryContext */ node = (MemoryContext) MemoryContextAlloc(TopMemoryContext, needed); } else //TopMemoryContext为空 { /* Special case for startup: use good ol' malloc */ node = (MemoryContext) malloc(needed); //申请needed大小的Mem...
Andrey's patches do two main things:Allow administrators to change the SLRU size to any value. Adds an associative cache. to make it performant to use a large cache value.Remember that the SLRU cache does a linear search for the desired page. That works fine when there are only 32 pages...
One of the things which is not implemented is tracking of available queues stored in database. Tracking of available queues is possible only after you have Agent registered and logged in the system. In difference of that you can do such tracking when you store configuration about queues in ...
else the function fails and returns null. To indicate the part of the pattern that should be returned on success, the pattern must contain two occurrences of the escape character followed by a double quote ("). The text matching the portion of the pattern between these markers is returned. ...
Things have changed in the last 4 years since this question was answered and the recommendation "don't use ILIKE" isn't true any more (at least in such a general way). In fact, depending on the data distribution, ILIKE with atrigram indexmight even be faster thencitext. ...