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37 | 37 | /* The alignment requirement of a `short'. */
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38 | 38 | #define ALIGNOF_SHORT 2
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39 | 39 |
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| 40 | +/* Size of a disk block --- this also limits the size of a tuple. You can set |
| 41 | + it bigger if you need bigger tuples (although TOAST should reduce the need |
| 42 | + to have large tuples, since fields can be spread across multiple tuples). |
| 43 | + BLCKSZ must be a power of 2. The maximum possible value of BLCKSZ is |
| 44 | + currently 2^15 (32768). This is determined by the 15-bit widths of the |
| 45 | + lp_off and lp_len fields in ItemIdData (see include/storage/itemid.h). |
| 46 | + Changing BLCKSZ requires an initdb. */ |
| 47 | +#define BLCKSZ 8192 |
| 48 | + |
40 | 49 | /* Define to the default TCP port number on which the server listens and to
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41 | 50 | which clients will try to connect. This can be overridden at run-time, but
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42 | 51 | it's convenient if your clients have the right default compiled in.
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591 | 600 | your system. */
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592 | 601 | /* #undef PTHREAD_CREATE_JOINABLE */
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593 | 602 |
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| 603 | +/* RELSEG_SIZE is the maximum number of blocks allowed in one disk file. Thus, |
| 604 | + the maximum size of a single file is RELSEG_SIZE * BLCKSZ; relations bigger |
| 605 | + than that are divided into multiple files. RELSEG_SIZE * BLCKSZ must be |
| 606 | + less than your OS' limit on file size. This is often 2 GB or 4GB in a |
| 607 | + 32-bit operating system, unless you have large file support enabled. By |
| 608 | + default, we make the limit 1 GB to avoid any possible integer-overflow |
| 609 | + problems within the OS. A limit smaller than necessary only means we divide |
| 610 | + a large relation into more chunks than necessary, so it seems best to err |
| 611 | + in the direction of a small limit. A power-of-2 value is recommended to |
| 612 | + save a few cycles in md.c, but is not absolutely required. Changing |
| 613 | + RELSEG_SIZE requires an initdb. */ |
| 614 | +#define RELSEG_SIZE 131072 |
| 615 | + |
594 | 616 | /* The size of a `size_t', as computed by sizeof. */
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595 | 617 | #define SIZEOF_SIZE_T 4
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596 | 618 |
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