Examples of org.apache.derby.impl.store.raw.data.BasePage

Package org.apache.derby.impl.store.raw.data

Examples of org.apache.derby.impl.store.raw.data.BasePage

org.apache.derby.impl.store.raw.data.BasePage
This class implements all the the generic locking behaviour for a Page. It leaves method used to log and store the records up to sub-classes. It is intended that the object can represent multiple pages from different containers during its lifetime.
A page contains a set of records, which can be accessed by "slot", which defines the order of the records on the page, or by "id" which defines the identity of the records on the page. Clients access records by both slot and id, depending on their needs.
BasePage implements Observer to watch the ContainerHandle which notifies its Observers when it is closing.
MT - mutable

                int[] createArgs,
                long pageOffset,
                boolean reuse,
                boolean overflow) throws StandardException
  {
    BasePage page = null;


    boolean releasePage = true;


    try
    {
      if (reuse)        //  read the page in first
      {
        // Cannot go thru the container handle because all read pages are blocked.  
        // do it underneath the handle and directly to the cache.  
        // Nobody can get thru becuase getPage will block at getting the alloc page.


        if (SanityManager.DEBUG)
                {
                    if (SanityManager.DEBUG_ON(SPACE_TRACE))
                    {
                        SanityManager.DEBUG(
                            SPACE_TRACE, "reusing page " + pkey);
                    }
                }


        page = (BasePage)pageCache.find(pkey);
        if (page == null)  // hmmm?
                {
          throw StandardException.newException(
                            SQLState.FILE_REUSE_PAGE_NOT_FOUND, pkey);
                }
      }
      else
      {
        if (SanityManager.DEBUG)
                {
                    if (SanityManager.DEBUG_ON(SPACE_TRACE))
                    {
                        SanityManager.DEBUG(
                            SPACE_TRACE, "allocation new page " + pkey);
                    }
                }


        // a brand new page, initialize and a new page in cache
        page = (BasePage) pageCache.create(pkey, createArgs);


        if (SanityManager.DEBUG)
          SanityManager.ASSERT(page != null, "page Cache create return a null page");
      }
      releasePage = false;
            page = latchPage(allochandle, page, true /* may need to wait, track3822 */);


      if (page == null)
            {
        throw StandardException.newException(
                        SQLState.FILE_NEW_PAGE_NOT_LATCHED, pkey);
            }     


      // page is either brand new or is read from disk, in either case,
      // it knows how to get itself initialized.
      int initPageFlag = 0;
      if (reuse) initPageFlag |= BasePage.INIT_PAGE_REUSE;
      if (overflow) initPageFlag |= BasePage.INIT_PAGE_OVERFLOW;
      if (reuse && isReusableRecordId())
        initPageFlag |= BasePage.INIT_PAGE_REUSE_RECORDID;


      page.initPage(initPageFlag, pageOffset);
      page.setContainerRowCount(estimatedRowCount);


    }
    finally
    {
      if (releasePage && page != null)

View Full Code Here

    }


    // RESOLVE: no translation!


    PageKey pageSearch = new PageKey(identity, pageNumber);
    BasePage page = (BasePage)pageCache.find(pageSearch);


    if (page == null)
    {
      return page;
    }


        // latch the page
        if (latchPage(handle,page,wait) == null)
        {
      // page was already released from cache
            return null;
        }


    // double check for overflow and deallocated page
    // a page that was valid before maybe invalid by now if it was
    // deallocated in the interum.
    // a page that is invalid can also become valid in the interim, but
    // we do not handle that.  The client must supply other locking
    // mechanism to prevent that (an allocatino happenning where there are
    // readers) if that is needed
    if ((page.isOverflowPage() && !overflowOK) ||
      (page.getPageStatus() != BasePage.VALID_PAGE))
    {
      // unlatch releases page from cache, see StoredPage.releaseExclusive()
            page.unlatch();
      page = null;
    }


    return page;
  }

View Full Code Here

    {
      allocCache.invalidate();
    }
    
    PageKey pageSearch = new PageKey(identity, pageNumber);
    BasePage page = (BasePage) pageCache.find(pageSearch);


    return page;
  }

View Full Code Here

        SanityManager.DEBUG_PRINT("Trace", "recreating page " + pkey + " for load tran");


    // Can't just call initPage because that wants to log an initPage
    // operation, whereas we are here because of an initPage operation in
    // the log already.
    BasePage page = null;
    boolean releasePage = true;
    try
    {
      // a brand new page, initialize and a new page in cache
      page = (BasePage) pageCache.create(pkey, reCreatePageArgs);

View Full Code Here

  {
    if (getCommittedDropState()) // committed and dropped, cannot get a page
      return null;


    PageKey pageSearch = new PageKey(identity, pageNumber);
    BasePage page = (BasePage) pageCache.find(pageSearch);


    if (SanityManager.DEBUG)
    {
      if (page == null)
        SanityManager.THROWASSERT(

View Full Code Here


      if (nextNumber == ContainerHandle.INVALID_PAGE_NUMBER)
        return null;


      // optimistically go for the next page
      BasePage p = getUserPage(handle, nextNumber,
                false /* no overflow page*/, wait);
      if (p != null)
        return p;


      pageNumber = nextNumber;

View Full Code Here

     throws StandardException
  {
    if (pageNumber == ContainerHandle.INVALID_PAGE_NUMBER)
      return null;


    BasePage p = getUserPage(handle, pageNumber, overflowOK, wait);
    if (p != null)
    {
            // make sure the page is not too full
            if (!p.allowInsert())
            {
                p.unlatch();
                p = null;


                // it is too full, make sure we are tracking it so we won't
                // see it again.
                allocCache.trackUnfilledPage(pageNumber, false);

View Full Code Here

   */
  protected BasePage getPageForInsert(BaseContainerHandle handle,
                    int flag)
     throws StandardException
  {
    BasePage p = null;
    boolean getLastInserted = (flag & ContainerHandle.GET_PAGE_UNFILLED) == 0;


    if (getLastInserted)
    {
      // There is nothing protecting lastInsertePage from being changed

View Full Code Here

    throws StandardException {


    if (foundPage == null)
      return null;


    BasePage ret = super.latchPage(handle, foundPage, wait);
    if (ret == null) {
      // page is still cached
      pageCache.release((Cacheable) foundPage);
    }
    return ret;

View Full Code Here

    StoredRecordHeader recordHeader = getHeaderAtSlot(slot);


    if (!recordHeader.hasOverflow())
      return super.fetchNumFieldsAtSlot(slot);


    BasePage overflowPage = getOverflowPage(recordHeader.getOverflowPage());
    int count = overflowPage.fetchNumFieldsAtSlot(getOverflowSlot(overflowPage, recordHeader));
    overflowPage.unlatch();
    return count;
  }

View Full Code Here

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