Hi, Xiaoran, I see. The code is checking if the bits other than rmgr bits, XLR_SPECIAL_REL_UPDATE and XLR_CHECK_CONSISTENCY are used.
Thanks for the explanation. Steven Xiaoran Wang <fanfuxiao...@gmail.com> 于2025年6月11日周三 10:13写道： > > > Steven Niu <niush...@gmail.com> 于2025年6月10日周二 17:56写道： > >> I'm confused by the code of XLR_RMGR_INFO_MASK and XLR_INFO_MASK. >> >> According to the definition of masks, the high 4 bits are for rmgr. >> >> /* >> * The high 4 bits in xl_info may be used freely by rmgr. The >> * XLR_SPECIAL_REL_UPDATE and XLR_CHECK_CONSISTENCY bits can be passed by >> * XLogInsert caller. The rest are set internally by XLogInsert. >> */ >> #define XLR_INFO_MASK 0x0F >> #define XLR_RMGR_INFO_MASK 0xF0 >> >> >> However, in function XLogInsert(), there is code: >> >> /* >> * The caller can set rmgr bits, XLR_SPECIAL_REL_UPDATE and >> * XLR_CHECK_CONSISTENCY; the rest are reserved for use by me. >> */ >> if ((info & ~(XLR_RMGR_INFO_MASK | >> XLR_SPECIAL_REL_UPDATE | >> XLR_CHECK_CONSISTENCY)) != 0) >> elog(PANIC, "invalid xlog info mask %02X", info); >> >> XLogInsert only allows the rmgr ,XLR_SPECIAL_REL_UPDATE and > XLR_CHECK_CONSISTENCY > set in the info. > >> #define XLR_SPECIAL_REL_UPDATE 0x01 >> #define XLR_CHECK_CONSISTENCY 0x02 >> >> As the XLR_SPECIAL_REL_UPDATE and XLR_CHECK_CONSISTENCY are of the low 4 >> bits, >> the above code is indicating the low 4 bits are for rmgr too? >> > > No, only the high 4 bits are used for RMGR, see the code under directory > 'src/backend/access/rmgrdesc' > > 'XLR_SPECIAL_REL_UPDATE' and 'XLR_CHECK_CONSISTENCY' are not RMGR info, > but they > can be passed by XLogInsert caller. > >> >> >> Did I misunderstand something? >> >> Thanks， >> Steven >> > > -- > Best regards ! > Xiaoran Wang >
