![]() After adjusting for total fat mass, total lean mass, and fasting insulin, serum leptin did not differ between users and nonusers of HRT (21.7 +/- 1.0 vs. abdominal fat and leg fat, as well as lean mass and insulin. Multiple linear regression analysis indicated that visceral fat was independently related to leptin (parameter estimate = 0.23, P < 0.05), after adjusting for s.c. Stepwise multiple linear regression analysis indicated that serum leptin could best be predicted from total fat mass, fasting serum insulin, and total lean mass. Total and regional body composition and fat distribution were determined by dual-energy x-ray absorptiometry and computed tomography fasting serum leptin and insulin, by RIA and REE, by indirect calorimetry. Xlog center plus#Subjects were 54 postmenopausal women, 45-55 yr old, 35 of whom used HRT (estrogen plus progestin). The objectives of this study were to: 1) identify factors influencing circulating leptin in postmenopausal women 2) determine whether HRT influences serum leptin after adjusting for confounding factors and, 3) identify potential independent effects of HRT or leptin on resting energy expenditure (REE). HRT may affect energy balance by influencing synthesis of the adipocyte-derived hormone leptin. This is not very compact for the case of moving data within a page, and might be improved in the future.Whether use of hormone-replacement therapy (HRT) influences menopause-related changes in body weight is unclear. This delta is based on byte-by-byte comparison. If GENERIC_XLOG_FULL_IMAGE is not specified for a registered buffer, the generic WAL record contains a delta between the old and the new page images. After redoing all changes, the locks will be released in the same order. The generic WAL redo function will acquire exclusive locks to buffers in the same order as they were registered. Thus, you typically do not need to do any explicit checks for unlogged relations. You do not need to do this explicitly.įor unlogged relations, everything works the same except that no actual WAL record is emitted. GenericXLogFinish() takes care of marking buffers dirty and setting their LSNs. There is no need to worry about calling GenericXLogAbort() during an error exit, either. The only actual critical section is present inside GenericXLogFinish(). between GenericXLogStart() and GenericXLogFinish(). Thus, you can safely do memory allocation, error throwing, etc. Since you are modifying copies of buffer pages, GenericXLogStart() does not start a critical section. Generic WAL assumes that the pages to be modified have standard layout, and in particular that there is no useful data between pd_lower and pd_upper. An error will be thrown if this limit is exceeded. The maximum number of buffers that can be registered for a generic WAL record is MAX_GENERIC_XLOG_PAGES. Keep in mind that buffers should be registered in the same order in which locks are to be obtained on them during replay. Registrations of buffers (step 2) and modifications of page images (step 3) can be mixed freely, i.e., both steps may be repeated in any sequence. Exclusive lock must be held on each target buffer from before GenericXLogRegisterBuffer() until after GenericXLogFinish(). However, it remains the caller's responsibility to pin/unpin and lock/unlock the buffers at appropriate times. Xlog center code#In other words, code that makes generic WAL records should never call BufferGetPage() for itself. No direct modifications of buffers are allowed! All modifications must be done in copies acquired from GenericXLogRegisterBuffer(). Please note the following points when using the generic WAL record facility: This will discard all changes to the page image copies. WAL record construction can be canceled between any of the above steps by calling GenericXLogAbort(state). GenericXLogFinish(state) - apply the changes to the buffers and emit the generic WAL record. GenericXLogRegisterBuffer can be repeated if the WAL-logged action needs to modify multiple pages.Īpply modifications to the page images obtained in the previous step. Typically this flag would be set if the page is new or has been rewritten completely. Xlog center update#Currently the only such flag is GENERIC_XLOG_FULL_IMAGE, which indicates that a full-page image rather than a delta update should be included in the WAL record. (Do not modify the buffer's contents directly.) The third argument is a bit mask of flags applicable to the operation. This function returns a pointer to a temporary copy of the buffer's page, where modifications should be made. Page = GenericXLogRegisterBuffer(state, buffer, flags) - register a buffer to be modified within the current generic WAL record. State = GenericXLogStart(relation) - start construction of a generic WAL record for the given relation. ![]()
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