SQL table growing inconsistently

问题

There is a SQL table which is growing rapidly and inconsistently compared to it's intrinsic data. To make it short, there is a windows service backing up the content of .txt files in this table, the files weight from 1KB to 45KB approx. hence the nvarchar(max) column used to store the content of those text files.

When running the sp_spaceused command on this table, here is the result:

name    rows    reserved       data      index_size   unused
Files   20402   814872 KB    813416 KB     1048 KB     408 KB

But when running this simple query, which gives me the total amount of data in bytes used by this table, the result is not anywhere near: (97231108 bytes).

SELECT (SUM(DATALENGTH(A)) +
        SUM(DATALENGTH(B)) +
        SUM(DATALENGTH(C)) +
        SUM(DATALENGTH(D)) +
        SUM(DATALENGTH(E)) +
        SUM(DATALENGTH(F)) +
        SUM(DATALENGTH(G)) + 
        SUM(DATALENGTH(H)) +
        SUM(DATALENGTH(I))) AS BytesUsed
FROM Files

RESULT: 97231108 bytes

The create statement for this table goes like this:

CREATE TABLE [dbo].[Files](
    [A] [int] IDENTITY(33515427,1) NOT NULL,
    [B] [nvarchar](100) NOT NULL,
    [C] [nvarchar](max) NOT NULL,  
    [D] [nvarchar](100) NOT NULL,
    [E] [datetime] NULL,
    [F] [nvarchar](2) NULL,
    [G] [datetime] NULL,
    [H] [nvarchar](100) NULL,
    [I] [int] NULL,

    CONSTRAINT [PK_Files] PRIMARY KEY CLUSTERED 
    (
    [A] ASC
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,
    ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
    CONSTRAINT [UK_Files_FileType_FileDate] UNIQUE NONCLUSTERED 
    (
    [D] ASC,
    [E] ASC
            )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,                           
            ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
        ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

    GO

    ALTER TABLE [dbo].[Files]  WITH CHECK ADD  CONSTRAINT [FK_Files_FileStatus] FOREIGN   
    KEY([F])
    REFERENCES [dbo].[F] ([F])
    GO

    ALTER TABLE [dbo].[Files] CHECK CONSTRAINT [FK_Files_FileStatus]
    GO

Temporary Fix: I have recreated the table (DROP & CREATE), then copied the old table's data into the new one, this made the table go from 65GB to 108MB.

My question is:

• What can make this table taking so much space and how can I prevent it from growing again?

回答1:

Installing the latest service pack fixed the problem.

来源：https://stackoverflow.com/questions/20960692/sql-table-growing-inconsistently