Ühel kenal päeval, P, 2007-02-11 kell 12:35, kirjutas Tom Lane: > Hannu Krosing <[EMAIL PROTECTED]> writes: > > What if we would just reuse the root tuple directly instead of turning > > it into a stub ? > > This would create a cycle of ctid pointers, which changes the lookup > > process from 'follow ctid chaint until the end' to 'follow the tid chain > > until you reach the start'. > > How do you know which one is newest?
By xmin,cmin of course . > What happens when you have to put a newer version off-page for lack of space? Then this scheme won't work. How about adding a new 2-byte field to header for in-page c_tid poiner for HOT ? It grows header from 26 to 28 bytes, but for MAXALIGN=4 the space usage would stay the same. > regards, tom lane -- ---------------- Hannu Krosing Database Architect Skype Technologies OÜ Akadeemia tee 21 F, Tallinn, 12618, Estonia Skype me: callto:hkrosing Get Skype for free: http://www.skype.com ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
